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Ask the RD: All About Food Combining


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Join Kelsey Kinney, MS, RD and Laura Schoenfeld, MPH, RD, as they answer your questions about ancestral and Paleo nutrition. A must-listen for anyone new to the Paleo diet or looking to improve their current Paleo diet based on their personal needs and health goals.

The content on this show reflects the opinion of Kelsey and Laura and does not represent the opinions of Chris Kresser, who has not reviewed the content of this podcast.

This week in our Ask the RD podcast, we’re focusing on food combining diets and whether or not there’s any science supporting those recommendations. We’ve received many questions about this topic so we’re going to cover the topic completely in today’s podcast. Laura and Kelsey will be addressing the following question in this podcast:

1. Is there any science behind the food combining diet?

Links Discussed:


About Laura: Laura is a Registered Dietitian with a Master’s degree in Public Health from UNC Chapel Hill. She is passionate about making traditional diets healthful and accessible for all her clients. You can learn more about Laura by checking out her blog or visiting her on Facebook.

About Kelsey: Kelsey is a Registered Dietitian with a Master’s degree in Human Nutrition and Functional Medicine. She works in private practice and recommends individualized dietary therapy focusing on biologically appropriate diet principles to aid her clients in losing weight, gaining energy, and pursuing continued health. You can learn more about Kelsey by visiting her website.


A big thank you to Amy Berger of tuitnutrition.com for the transcription of this episode. 

LAURA:  Hi everyone. Welcome to the second episode of ask the RD. I’m Laura; I’m a graduate student at UNC Chapel Hill studying public health and nutrition, and I’ll have my RD at the end of 2013.

KELSEY:  And I’m Kelsey, a registered dietitian specializing in whole food ancestral diets, and I’m working on my Master’s in nutrition and functional medicine.

LAURA:  Thanks for joining us for our second edition of Ask the RD. We’re really excited that this is a new feature on Chris’s website and we hope that you’ll enjoy learning about nutrition-related topics. And just as a reminder, as always, this is just general advice and should not be used in place of medical advice from a licensed professional. Are we ready to get started with our podcast, Kelsey?

KELSEY:  Sure! Okay, so I’m going to ask you this question. I know you’re going to do a of of talking about it but I’ll do some interjections here. So here we go. Is there any science behind food combining diets?

LAURA:  Okay, so first what I want to do is explain to everyone what a food combining diet is. It’s not something that everyone’s always familiar with, and honestly, being an RD, we don’t often learn about this kind of stuff in school, so I had to do a little research for myself about what a food combining diet is. So the basic principle behind a food combining diet is that different foods require different pH levels to digest properly, and they all have different transit times in the GI tract. And the belief is that eating certain food combinations—specifically, protein-rich foods combined with carbohydrate-rich foods—these combinations are harder to digest, which supposedly decreases nutrient absorption, and also the combination of the foods supposedly would cause food to sit longer in the GI tract, which could promote gas, bloating, and the buildup of toxins from food not moving through quickly enough.

So people who recommend food combining diets usually have specific recommendations for what type of foods to eat at the same time, and which foods to eat separately. One example of one of the more original food combining diets is called the Hay Diet, and that one has three different types of food. They’re  either acid, alkaline, or neutral. And this particular diet suggests that combining acid foods like meat, fish, and dairy, with alkaline foods like potatoes and rice, would lead to a buildup of toxins. Some people even suggest that the reason this would occur is because these foods require different types of enzymes that end up canceling each other out when used in the same meal.

So, there are four common rules in food combining, depending on which food combining diet you’re looking at. Number one is to always eat fruit—and especially melons—on an empty stomach, or at least twenty minutes before eating anything else. Number two is to eat starches alone, or with cooked non-starchy vegetables. Number three is to eat meat, dairy, fish, and eggs, and other high-protein foods alone or with cooked non-starchy vegetables. And number four is to eat nuts, seeds, and dried fruit with raw vegetables.

And these are all recommendations that aren’t really supported by any evidence, and most of them are actually myths.

KELSEY:  Right. And I have to say, I tried to find research on this stuff, and there’s really just nothing, to be honest, which is kind of surprising for something like this. I feel like these kinds of diets have been recommended for a long time now, and I think if I’m correct, I believe they have some roots in the old Chinese medicine type of thing, so it’s just interesting that it’s been around for so long and it has really no research to back it up.

LAURA:  Right, and honestly, as we always say, it’s not that lack of evidence is evidence against, but some of the stuff that we’re talking about, there is actually some level of disconnect with biochemistry. So we’re not saying that this is proven false, but we’re gonna talk about a few reasons why a lot of it’s not really accurate, and better ways to improve your digestion and your weight loss attempts. So the biggest myth put forth by these food combining diets is that carbohydrates can’t digest in an acidic environment. There is some truth to the idea that carbohydrates digest better in an alkaline environment due to the activation of the amylase enzymes. Eating carbohydrates alone is not going to actually prevent them from being acted on by stomach acid, because stomach acid is released when we eat any type of food, not just protein.

KELSEY:  Right. You start to produce stomach acid when you just smell food, whether it’s a carbohydrate or not, so you’re already doing that.

LAURA:  If your stomach’s empty, it’s acidic. It really only drops in acid when food enters it and your stomach…in a healthy individual, your stomach should release acid when any food goes in, not just protein. So once these contents of the stomach move into the small intestine, the pancreas then releases its own digestive enzymes, along with bicarbonate, which is an alkaline secretion that neutralizes the stomach acid, and this will activate the pancreatic enzymes that work to break down mostly the carbohydrates and fat, but some protein is also broken down in the small intestine. But ironically, the pancreas actually releases these enzymes in response to the drop in pH when the acidic stomach contents enter the small intestine. So, based on physiology, the more acid that your stomach produces, the more alkaline the pancreatic response will be. So in that case, eating protein with carbohydrates or fats might actually increase the digestive capacity in the small intestine. So that’s kind of exactly the opposite.

KELSEY:  Completely backwards

LAURA:   Right, so if nothing else, it won’t hurt to have protein in there as well, and it could actually potentially stimulate digestion if you’re eating things at the same time.

KELSEY:  Yeah, and you know, your body is making all these enzymes that get released into the small intestine—lipase, amylase, and trypsin—and all of those work on different components of food: carbohydrate, fat, protein. So the body is releasing all those things into the small intestine basically knowing it’s going to get a big mix of what you’re eating because when the food you’re eating goes into the stomach, it all gets mixed up with your stomach acid into a substance called chyme, and that’s what gets released into the small intestine. So everything’s already mixed together, and I think that’s also sort of one of those myths that goes along with this theory—that things sort of get digested sequentially, and that’s why you eat things in a certain order, which is totally untrue.

LAURA:  Right. It’s like everything gets blended and then based on the macronutrient contents in your stomach, it’ll be released into the small intestine at different rates. So, say you’re eating just carbohydrates. Generally, the time that it’s going to spend in the stomach is a little bit shorter, and then fat is the exact opposite. So the more fat you’re eating, the longer it’s going to stay in your stomach. So it’s not going to change how much the foods get digested; it’s just going to change maybe the gastric emptying rate.

KELSEY:  Yeah, exactly.

LAURA:  I think it maybe could feel better if you’re just eating carbohydrates and they get released quicker, but in the same sense, it’s also going to make you get hungrier faster.

KELSEY:  Right.

LAURA:  So there’s downsides and upsides to eating one macronutrient at a time. But there’s also other issues with these recommendations that the food combing diet gives. One of them is that we should only eat fruit on its own. That’s fine for healthy people, but anyone dealing with a blood sugar control issue or insulin resistance really shouldn’t be eating carbohydrate foods on their own. As I just mentioned, the whole issue is that carbohydrates, if they’re on their own, get digested and absorbed into the bloodstream much faster. So adding protein or fat to a carbohydrate source can help blunt the glycemic response to that food, and it’ll reduce the spike in blood sugar that would usually come from eating that carbohydrate food on its own. So if you have diabetes or if you have poor blood sugar control, eating fruit on its own is really not a good idea for you. And if you have a healthy blood sugar response, I feel like it’s okay to eat fruit on its own, and you shouldn’t have to worry about whether you’re combining it with far or protein, but it’s actually a really good way to increase the satiety of that fruit if you eat it with something like nuts or cheese that has a little protein or fat in it. So I don’t think that eating fruit on its own is necessarily helpful; I just that some people can tolerate it better than others.

KELSEY:  Right. I would totally agree with that.

LAURA:  And it’s something that we learn as dietitians, and also it’s just the way physiology works with diabetes that you don’t want to be eating pure carbohydrate. Because part of the problem is that you’re having those big spikes in blood sugar, and either you’re insulin resistant, or if you have type 1, you’re not producing insulin, but either way, it’s really not a good idea to just have a sudden hit of pure carbohydrate with no fat or protein to buffer it.

So another issue is that certain nutrients are actually better absorbed when they’re combined with fats. The fat-soluble vitamins by nature mix in with fat and are better absorbed that way, but there’s also some phytochemicals and things like mixed carotenoids that actually can be digested better if they’re mixed with fat. So if you’re eating fruit or vegetables with no fat added, you’re maybe not getting as much of those nutrients as you would be if you actually combined them with a fat source, like butter, or olive oil, or nuts, or however you’re eating those fruits and vegetables. There’s actually a study in the American Journal of Clinical Nutrition that demonstrated that salads with lettuce, tomatoes, and carrots require a fat-containing dressing to absorb the mixed carotenoids in them. And these carotenoids are important because they’re found to be protective against chronic diseases like heart disease and cancer, so it’s really important to eat fat with your vegetables and other plant foods in order to maximize the nutrient absorption from these foods. And part of the problem with the food combining diets is that they recommend avoiding fat—especially with fruit—but also with vegetables, they say just eat starchy carbs or protein. So you’re not necessarily getting the fat to help absorb those nutrients. It doesn’t defeat the purpose of eating vegetables, but it definitely reduces their benefits.

So, honestly, my belief is that one of the reasons these food combining diets work for some people is because they end up eating less food at one sitting. So if you’re only eating one macronutrient at a time, you’re probably going to eat a lot less of it. Just as an example, a dry potato is not something that I find very appetizing. I’m not sure about you, Kelsey…

KELSEY:  Yep, I’d agree with that.

LAURA:  A baked white potato with nothing on it is not something that you’re gonna want to eat much of. I mean, neither is a huge chunk of butter, in my opinion. I wouldn’t necessarily sit down to a quarter cup of butter, but when you combine the two—the starches and the fat together—obviously this is a very delicious combination and it’s very easy to eat much more volume of that food. So this can be a problem for two reasons. One of the big issues is that overeating obviously causes weight gain if it happens on a regular basis, and so there is some truth to that calories in, calories out equation, if it’s not a complete and straightforward picture. But if you’re always eating more than you need, then yes, you are going to gain weight. And a second issue here is that eating big meals in general just makes it hard to effectively digest your food because your stomach acid and the other enzymes your gut is producing get diluted by the volume, so your GI tract is going to have to work a lot harder to handle that extra volume. So this could be a reason why some people do experience digestive benefits from following these food combining plans, but, y’know, just because you’re eating less, that doesn’t require you to follow this strict food combining. You can just eat less at a meal and kind of pay attention to your satiety factors when you’re eating.

KELSEY:  Exactly. And I think…when I did my research on this, on the food combining diets, the one article that I found about it was about weight loss. And basically, what they compared was a balanced diet, which had 25% protein, 47% carbohydrate, and 25% lipids. That was the balanced one…I messed that up. That’s backwards. So that was the food combining diet, and the balanced diet was 25% protein, 42% carbohydrate, and 31% lipids. So basically, they were very close. The balanced diet had a little bit more fat than the food combining diet, but the major difference was that they were doing the food combining diet or they were just eating things together.

LAURA:  And they were on a calorie controlled…

KELSEY:  Right. That was the biggest thing, is that they were only eating a thousand and a hundred (1100) calories a day, so that’s super low-calorie. So I think…and in this case, they found no difference between the two diets in terms of weight loss. But really, what we can take away from that is that a low-calorie-diet probably is going to give you some weight loss no matter how you do it. But that’s exactly what you’re talking about though, is just that if you’re eating the same amount of calories, you’re gonna lose the same amount of weight as someone who’s doing a regular diet or a food combining diet. But, if you’re not paying attention to calories, then you’re right. Something that’s low-reward, like a food combining diet, is—and just by the fact that it’s food combining, you can’t eat starch and fat together, that’s gonna make you eat less, so automatically you might be at a lower calorie intake than someone on a regular, normal, balanced diet.

LAURA:  Right. So that is something that I did want to point out is that these food combining diets tend to be simple when it comes to the number of ingredients. And as you were just mentioning, research suggests that limiting the variety and the pleasurability of your food can actually help promote weight maintenance and might even promote weight loss in some people. And as you mentioned, that’s called the Food Reward Hypothesis, which I imagine most of our listeners have heard of before, but it is a strategy that Chris has written a lot about in the Personal Paleo Code program, and a lot of the information he shares came from Stephan Guyenet, who writes the blog Whole Health Source.  So he’s described research suggesting that highly palatable diets increase the body’s fat setpoint, and that’s the way it contributes to obesity. So, if people are trying to lose excess fat, his hypothesis is that eating a low food reward diet can be helpful for fat loss. So, to me, it sounds like this food combining plan is actually a really good example of a really low food reward diet. As you mentioned, the combination of fat and carbohydrates is a very palatable one, and I’m sure everyone can speak from experience that things—when you combine fat and carbohydrates—are usually the most delicious. So this could be another explanation for why people experience weight loss on a food combining diet. And the fact that any attempt to control what you’re eating is usually going to lead to a lower caloric intake at first. So that could be… if it’s a Paleo diet, a vegan diet, low-carb diet, or even a low-fat diet…when you first start a diet like that, you’re gonna substantially drop your caloric intake in the beginning.

KELSEY:  Right. And I want to mention something here too, just along the lines of being on a diet and controlling what you eat is that for some people, I do think that grabbing any kind of diet like this can be another way for them to control their eating habits, because they have more rules to follow, which for some people, they like that. It helps them to just feel more in control of what they’re doing, and their weight, and everything in their life. And I think this can be a really dangerous game to play for some people, and especially for women in particular. We just sort of go on these diets after diets after diets, following more and more rules, and I think that for a lot of people, this can be really stressful. Just more stressful than eating whole, natural, real foods, and just basically focusing on that one goal, that one rule. So adding these other rules can be stressful, and especially, I think the two big reasons that people do this kind of diet is either to help with digestive distress, or to help with weight loss.

LAURA:  Right.

KELSEY:  And if you’re stressed out, you’re impacting both of those in a negative way.

LAURA:  That’s for sure.

KELSEY:  So stress really impacts your digestive system, and when you’re stressed out, you’re not focused on digestion. So you might experience more bloating and gas, which might be the exact things you started this diet in the beginning to get rid of.

LAURA:  Yeah. And I think with the weight loss thing, ou might find that you lose weight at first, but we don’t want to be encouraging a diet that’s not sustainable for life, hypothetically. It’s one thing to do a challenge, like just to do a month of clean eating or something like that, but if you’re gonna do a diet for weight loss, you really have to be doing something that you think you can eat that way for basically the rest of your life. Maybe not 100% of the time, but at least 80% of the time, it should be something you’re comfortable doing, and you’re not feeling deprived, or feeling that you’re spending way too much time thinking about what you’re eating. And I don’t know if this food combining diet fits those boundaries.

KELSEY:  Right. And I think it’s probably different for very many people. Someone might be able to follow this easily and it doesn’t affect them at all, stress-wise, but for another person, it could be really, really stressful to try to always be following these rules. And to be honest, it seems like there are a lot of them.

LAURA:  Yeah, and they’re kind of arbitrary. I mean, I know strict Paleo has a lot of semi-arbitrary rules, and I know we’ve mentioned that neither of us would consider ourselves strict Paleo, so I don’t necessarily think strict Paleo is a great choice for people that don’t have autoimmune disease, or celiac, or that kind of thing that is going to make a huge difference if they follow the diet or not. But, I mean, I do think that the rules for Paleo at least are a little bit more straightforward and you can easily recognize what something is when it’s real food. But knowing whether something should be combined with something else…I mean, I saw some rules that were like, “acid fruits can’t be combined with sweet fruits,” and I’m like, what does that even mean, you know?

KELSEY:  It’s confusing, yeah.

LAURA:  Yeah. Can you imagine going out to eat and getting a fruit salad or something, and being like, “Well, I have to eat the oranges separately from the cantaloupe…” And I’m just like… that would just drive me crazy. And I feel like the perceived benefits from doing that are so potentially low that it doesn’t make sense for me to recommend that as a method. And I think there’s a lot of other, actually evidence-supported ways to support digestive function and weight loss that don’t require that level of mental involvement, y’know?

KELSEY:  Right. So I think it’s a good idea if you’re someone who has considered this diet, or maybe you’re already on this diet along with Paleo, it’s a really good idea to ask yourself why you’re doing it. And if the reason is weight loss, or if it’s digestion, then we’re gonna talk about some better ways to achieve those goals that you’re working towards, rather than adding more rules onto yourself like this diet does.

LAURA:  Right. And I think especially with the digestive issues, I think there’s some really helpful techniques that don’t require so much rules. So we can actually talk about that now.

KELSEY:  Perfect.

LAURA:  Yeah, ‘cuz I just think there are a lot of people out there that the reason they get on a Paleo diet is because of digestive issues, which is great, but just because you’re not eating wheat doesn’t mean you’re gonna be digesting your food as well as you could be. So anyway, the recommendations I have for increasing digestive strength is, first, like I mentioned before, avoiding overeating at any meal. And by overeating, I mean eating to the point where you feel stuffed. Like I mentioned before, having excess volume of food in your stomach at one time is just going to make it more challenging to digest the food, no matter what you’ve eaten. So, I mean, not that I think that people tend to overeat on Paleo, but I think sometimes when you get that idea in your head that you can eat anything as long as it follows the certain rules…that overeating’s a little more likely, y’know? And I’m not saying people have to count calories, or do any sort of crazy calculations, but I think just paying attention to what you’re eating, and making sure you stop eating when you get maybe to 80-90% full and you’re not getting to that 100% or even over, and feeling like you’ve stretched your stomach out to uncomfortable size.

KELSEY:  Right. And I think here it’s a really good idea to incorporate some kind of mind-body activity. Even something…I do yoga, and I feel like it makes me more aware of everything going on in my body.

LAURA:  Definitely.

KELSEY:  And when I’m doing it on a regular basis, I do feel like I pay more attention to how full I am, whereas other times maybe I’m just, y’know, I don’t care, or I don’t notice. It’s just not something I think about. So I do think that if that’s something you’re having trouble with, y’know, being mindful of how much you’re eating, and knowing whether you’re overeating, undereating, or eating just the right amount, that doing those activities—yoga, tai chi, meditation, anything like that—would be really beneficial.

LAURA:  Yeah, and there are a lot of different behavioral strategies that you can use to increase your digestive function. So yoga’s a good example, and also just sitting down for all your meals, without having distractions, and taking at least twenty minutes to eat your food. I mean, I know that sounds really basic, but I think a lot of us tend to not necessarily give mealtime the attention it deserves. I mean, I know I tend to be a bit of a workaholic and I’ll be on the computer while I’m eating, and it’s not a great practice to get into and I know I definitely eat mindlessly when I’m doing work at the same time. So definitely trying to avoid things like not having your phone, not having your laptop or iPad, not having the TV on when you’re eating is a really good idea. Um, and just eating slowly. I mean, sometimes that’s difficult for people, especially in the morning if they’re rushing out the door and they’re just shoving, you know, their eggs and bacon in their mouth, and they’re ten minutes on their commute and they start feeling digestive distress because they didn’t sit down and eat that food.

KELSEY: Plus, if you’re like, wolfing things down like that, you’re not chewing thoroughly, and that chewing serves a very important purpose, because it breaks down that food. It starts that process so amylase can work on it, already in the mouth. Y’know, amylase is one of the enzymes that works on carbohydrates, so you kind of want to start that process right away, break down the food so it’s got more surface area, so acid and amylase and all those other enzymes once it gets down to the small intestine can actually do their work on that. And if you don’t, if you’re just taking these huge bites of food, it’s gonna have a harder time breaking those foods down.

LAURA:  Right. And just the simple act of chewing actually primes your digestive tract to start secreting those enzymes and acids and stuff, so if you’re eating on the run all the time, or eating standing up, and just, y’know, taking huge bites of your food, yeah, that’s gonna definitely reduce your digestive capacity, and it won’t matter what you’re eating necessarily. You’ll feel bad whether you ate your fruit on its own or if you combined it with a couple of nuts or whatever. So, definitely I think a behavioral approach is a really important thing to do to start. Another simple way is to actually just take hydrochloric acid and digestive enzyme supplements, because that can help lower the pH of your stomach, and it’ll help improve the digestion of your food overall. And so Chris suggests a couple of supplements: Betaine HCL/Pepsin from Thorne Research and Super Enzymes from Now. So they are good products if you’re looking for a bit of a digestion assist. And then there’s obviously other combination acid/enzyme supplements out there like at Whole Foods or your local health food store, and those will make a huge difference in digestive function, especially if you’ve recently changed to a Paleo diet and you might be eating more protein than usual, or if you’re just one of those people that struggles with proper digestion. Maybe you’re stressed and your stomach acid is low; or maybe you just don’t have the same level of digestive health that you’ve had in the past and you want to kind of support it using external sources.

So that’s, I mean, that’s kind of like the “quick and dirty” way to increase your digestive capacity, but another way is to actually reduce the amount of liquids you take in when you’re eating. So try to make sure you get most of your fluid intake outside of mealtime rather than at mealtime, because water and other beverages will actually dilute your stomach acid and reduce your overall digestive function. So, obviously we recommend eating things like bone broth, but I don’t necessarily think it’s a great idea to have, like, eight ounces of bone broth and then eat your food right away. I think it’s actually better to try to keep the bone broth by itself and drink it outside of meals, because if you’re struggling with adequate digestion, then taking a lot of bone broth fluid in is actually going to prevent you from digesting your food as well, so…

KELSEY:  Yeah, and I think for a lot of people, we just see mealtime as the time where we’re doing our liquid drinking.

LAURA:  Mm-hmm.

KELSEY:  And I think that can be a problem for someone who already has impaired digestive capacity or is experiencing GERD. Something like that, where we definitely know there’s something wrong with the digestion already—likely that they aren’t producing enough HCl or digestive enzymes—and then like you said, they’re just diluting it even further, especially…I know that one of the common recommendations for weight loss is to go to a restaurant and chug a glass of water right before you eat…

LAURA:  Oh, yeah!

KELSEY:  Yeah, and that’s a horrible idea! Especially if you have any kind of digestive problems to begin with. So I really try to recommend for anyone dealing with digestive issues to, like you said, kind of keep those liquids outside of mealtime. And a little bit of wine or a little bit of liquid is okay, but for the most part, consuming the majority of your liquids outside of mealtime is a really good idea.

LAURA:  Well, and I think actually wine is a…it’s like a stimulant for your digestion. I mean, obviously this is talking about having, like, a glass with dinner, but I think that kind of goes to show you there’s a reason why the cultural practice of  drinking wine with food is… I don’t think it’s any coincidence that that exists. But you don’t often see a cultural practice of chugging water before you eat your meal.

KELSEY:  Right. That’s a new one for us.

LAURA:  That’s an American cultural thing. We like to do everything backwards. But yeah, so definitely try to stick to limiting your fluids, and if you are drinking wine, I mean, that’s a good way to increase digestion as long as you’re just drinking a small amount.

KELSEY:  Right, one glass. Yeah. And one other thing I wanted to say about digestion is that I…I wanted to reach out to people who maybe have tried this diet and they feel like it’s really helping them, because that is certainly possible. And I think that one of the biggest reasons why that might be the case is that the person has low stomach acid or has problems producing enough digestive enzymes, and so when they follow this food combining diet, I think it’s just…it’s hard to eat a lot of protein, because you have to eat it separately. So if I was going to follow this diet, I would be eating way less protein than I do now because now I eat protein with every single meal, and I wouldn’t be able to do that just by way of what the rules are for this diet.

LAURA:  Right.

KELSEY:  So since stomach acid helps to break down protein, if you’re not eating a lot of protein and you have low stomach, you’re gonna feel better. But that doesn’t mean you shouldn’t eat a lot of protein; it means that you should fix the root cause of the problem, which is the low stomach acid.

LAURA:  Right. Exactly. So I know that’s something that might come up with people switching from a vegetarian diet to Paleo, is that they’re suddenly eating way more protein than they’re used to, and that can be challenging to your digestive system when it’s kind of adapted to your low protein diet. And there’s ways to increase your stomach acid and it’s gonna take time for your body to readjust to what you’re eating, but that doesn’t mean that the protein is bad for you, or that it’s, like, sitting in your digestive system, rotting or something like all that crazy…like…people talking about, “Oh, the food just doesn’t get moved through and it rots in your—”

KELSEY:  And honestly, now that I’m thinking about this, probably reading all of that and thinking about it as you’re eating would probably give you a stomach upset. Because there’s a big connection between what we think and what actually happens physiologically, so if you’re just stewing there, thinking about how your food is just rotting in your stomach, it wouldn’t surprise me if you would get a little bit of digestive upset just by thinking that.

LAURA:  Right. I mean, if you expect something to not feel good when you eat it, it’s probably not going to feel good when you eat it. So, I mean, yeah, there’s definitely some level of information overload in nutrition these days, and certainly you don’t want it to be incorrect information, so when people are getting told that kind of stuff it definitely…it can make a big difference in their perceived tolerance of a diet. So, yeah, there’s obviously lots of different ways to increase digestive function, but I think taking the enzymes and the HCl supplements, and then just making sure you’re eating slowly and paying attention to what you’re eating and not distracted, and limiting fluids at a meal, and I think for 80% of the people out there that might be enough to help them digest very efficiently.

KELSEY:  Yeah. And I think if you’re at that point where you’ve really implemented all of those behavioral components and you’re still having some problems, it’s a good idea to probably get your gut bacteria checked. So see if you have any degree of dysbiosis, or maybe get checked for small intestinal bacterial overgrowth, which can cause gas and bloating for a lot of people. So if this doesn’t fix everything for you, make sure you check out those even deeper root causes that could be playing into your case, but absolutely try these behavioral techniques first because for the majority of people, it really, really helps.

LAURA:  Right. Another thing is H. pylori overgrowth can reduce stomach acid secretion, so, hypothetically, if you have…I mean, I think…what is it, 80 or 90% of the population has H. pylori in their stomach, so it’s not that you have it; it’s that it’s overgrown and is shutting down your stomach acid production. So that’s always a possibility for people, and if, like Kelsey said, if you’re doing all these strategies and it’s not working, then there’s probably something else at the root of the issue that will probably require more extensive testing to figure out.

KELSEY:  Yeah. But I think this is the place to start. And I think it’s important that we talk about it today because a lot of people, instead of trying some of the behavioral things—and I think this goes for many, many health conditions, including if you’re trying to lose weight—will often try to look more to the food side of things, because we feel like we can control that more, rather than, say, exercising more, or just…y’know what I mean? It’s…people, they want to find…either someone will be very into the exercise side of things or they’ll be very into the food side of things and they tend to look for answers in those places way deeper than they’d ever even consider kind of the basic, general recommendations for all of the other lifestyle components.

LAURA:  Right, And so it’s like there are so many other things that can play into digestion, like sleep, and stress, and infection, and that kind of stuff. And it’s…you’re right. People tend to say it’s either my diet or my activity when it comes to almost any health concern, and that’s definitely obviously something you want to address, but at the same rate, it’s not the end-all be-all of…if you have the perfect diet, it’s gonna fix your whole life and make you immortal and you’ll never die and all that stuff.

KELSEY:  Wouldn’t that be great?

LAURA:  Yeah, well, sometimes I wonder if that’s what people expect to happen when they switch to Paleo. It’s like, “Wait, what? I’m still getting older? What’s going on?” It’s not the Benjamin Button diet, you guys… but yeah, so I think the digestion thing is probably a big reason why people do food combining, but again, we mentioned the other potential reason for it is weight loss. So if your goal is weight loss and you find that the food combining is helping, it’s more likely to do with the fact that you’re following a simple diet, which is limited in ingredients and it limits the overall food reward of your meals. So one easy way to do this that doesn’t require the food combining stress is just to reduce the amount of added fat in your meal. So this means that if you’re eating fatty cuts of meat of foods that contain fat, such as avocado, or coconut, or that kind of thing, you can eat those along with your starches, but you don’t actually add fat to your starches. So that means that if you’re eating something like a steak and a baked potato, don’t put butter on the potato if you’re trying to lose weight. And I know, like I’m sure alarm bells are going off in people’s heads saying, “What? But I can’t eat potato on its own, that’s so high-carb” or whatever, but, I mean, this is the recommendations for the simple Paleo diet and I’m just relaying the information to you. So, if you don’t want to eat starches and you’d rather have the butter on the steak, then that’s your call. But as far as the evidence goes, I think…

KELSEY:  And even butter on steak would increase that reward value.

LAURA:  Oh, my gosh, yes. I’ve had that before.

KELSEY:  Yeah, it’s eating things plainly, so, having a steak that’s a fatty cut is fine, but like you said, if you’re gonna add butter to that, that definitely increases the reward value. And if you had a baked potato plain, that’s very simple and not very rewarding. Add butter and tons of spices into that and bam, you’ve got something really rewarding to the brain right there.

LAURA:  As I was saying, the steak and potato thing, it sounds kind of boring. I mean, if you’re just eating a plain steak, and, in more extreme examples, you don’t add salt to the steak or the potato. I mean, that actually, if you think about it, doesn’t sound like that great of a meal. But if you say, oh, it’s a steak cooked with like, salt and pepper, and then the butter and the sour cream on the potato, I mean, it really starts racking up in food reward and even just calories, so it’s like you’re kind of getting two birds with one stone if you drop the additives to the food. So, Stephan Guyenet gives a really extreme example of a low food reward diet by…he says to pick three foods and eat only those foods throughout the entire day. So his example is choosing a meat, a starch, and a vegetable, to make sure you’re getting the good variety of fat, protein, and carbohydrate and fiber, and that kind of thing, and he uses…his example meal would be potatoes, broccoli, and beef, with no salt or fat added. So obviously that sounds pretty extreme and I’m sure he doesn’t suggest doing this on a daily basis for the rest of your life. But I do think if someone is really trying to lose weight and is struggling, that doing a couple days a week of a very simple diet like that could possibly promote weight loss. If nothing else, you’re probably not going to be eating as much, and then you’re also potentially reducing the food reward value of your diet. And if Stephan’s theory is correct, then that will help lower your body fat setpoint. So, I mean it’s obviously a lot of theory, but I think the theory is more supported by evidence than the food combining theory.

KELSEY:  Yeah. And just if you even think about it, we would not have ever really combined our food this way. When you think about it, I don’t think that necessarily makes sense from an ancestral point of view, whereas having a low food reward value makes a lot of sense. Y’know, we would’ve just been eating pretty plain things. And now we’re so used to just getting taste overload from all the processed foods that I think that’s probably a big reason why people start to lose weight in the first place when they go from a standard American diet to a Paleo diet, because even that difference is going to be big in terms of a lowered food reward value. So if you’re still having trouble just in a Paleo diet, taking it that step further—and again, it’s not a forever thing; this is really a therapeutic diet for weight loss—but it can be very, very useful.

LAURA:  Yeah, and I mean obviously not to put down our friends that do recipe blogs and cookbooks and that kind of stuff, but honestly, if you’re making Paleo donuts every day, or, I know this sounds like it should be pretty straightforward, but sometimes I do wonder if people realize that, like, a Paleo treat is still a treat, and it’s not a free food that’s just going to help you lose weight no matter how much you eat of those foods. I mean, yeah, maybe you’ll see someone like PaleOMG or whatever who’s in really good shape, and she cooks all these crazy foods, but she’s also doing a ton of physical activity. So people really need to pay attention to their own lifestyles and if you’re working a 9-to-5 desk job and only being able to exercise like four times a week, then yeah, you’re probably not going to be able to eat Paleo donuts and Paleo cupcakes and stuff on a regular basis.

KELSEY:  Right. Unfortunately.

LAURA:  Yeah, and maybe that goes without saying, but again, even if you take it down to the point of people thinking, yeah, okay, butter is fine, let’s use butter, great. But then people start to put it on everything and they wonder why they’re not losing weight. And it’s like, well, it’s probably because you’re overdoing the butter on everything, like potatoes, sweet potatoes, vegetables, steak. You don’t need to overdo it just because it’s not bad for you.

KELSEY:  Exactly.

LAURA:  And again, this really is only relevant to people who want to lose weight, so if you’re happy with your weight or you’re even trying to gain weight, then adding butter to anything you want is perfectly fine. So again, just the caveat here is: weight loss, like, resistant weight gain that you’ve had, if you’re trying to lose that last ten to twenty pounds, you’re probably going to have to make some more serious cuts as far as what level of variety you’re eating and what level of additional tastiness you’re adding to your food.

KELSEY:  Right, exactly.

LAURA:  But I’m not trying to be Debbie Downer and obviously people can have desserts and they can enjoy their food as much as they want. But if your goals are to lean out and you’re struggling with it, then sometimes you just have to make the decisions—do you want to be 10% body fat, or do you want to be able to eat Paleo cupcakes when you want? And that’s your decision, you know? You make that call and if you decide you want to enjoy your food and you don’t care what your body composition is, then great. That’s probably fine, and you’re probably going to be healthy and enjoy life. And, there are certain people who want to look a certain way and they’re gonna need to be a little bit more strict about what they’re eating.

KELSEY:  Right. Like we say with everything, everybody’s different.

LAURA:  Yeah. And maybe your goal is to just fix your autoimmune disease, and maybe that means that you have to avoid different things than someone who wants to lose twenty pounds needs to avoid.

KELSEY:  Exactly.

LAURA:  I hate to try to make it sound like we ever think anyone should blanket follow any recommendations that we give, and I hope we’re trying to make it clear that it’s really goal-dependent, what you eat. So this Simple Paleo diet is not for everyone, and if it’s not something that’s interesting to you then don’t do it.

KELSEY:  We’re just here to give you the information.

LAURA:  Yeah. Like if…it’s interesting, ‘cuz I think sometimes people assume that there’s one thing that everyone has to eat, like one style, and that it’ll work for everyone no matter what their goals are, no matter what their history is, no matter what their genetics are, and I’m hoping Kelsey and I have been clear in the past that everyone’s different and your goals are gonna dictate the strategy that you take.

KELSEY:  Absolutely.

LAURA:  Rant over! I’m just coming off of reading that Health-Bent article about it, so I’m a little bit…a little prickly about it, but…

KELSEY:  Sure. No, I understand, And if you haven’t seen that article, it’s worth a read. It might make you a little mad, but it certainly opens some questions up for sure.

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LAURA:  Anyway, so I hope we’ve done a pretty good job at discussing the food combining diet, and at the end of the day, one of the problems with this theory is that it was mostly developed in the early 1900’s, and honestly, we really didn’t have a complete—well, we still maybe don’t have a complete understanding—but we had much less complete understanding about how the human digestive system worked at that time, so it might have been a reasonable theory back then, and I’m sure it has some level of benefits when being put into practice, but I don’t really understand why people are still promoting it as a weight loss or detox diet, since there isn’t any research to support the efficacy. And really, the only study out there that’s even tested the theory, like you mentioned, it didn’t show any benefit to the diet.

KELSEY:  Absolutely. So, unfortunately, yeah, no evidence to support it. A lot of biochemistry to refute it. And like we said, if you’re someone this has worked for, there are a few reasons why that might be the case. And so you might want to start thinking about whether it’s better to go about it in a different way to accomplish those goals. But if you’re liking what you’re doing and it’s working for you, by all means, keep doing it. We’re just here to answer the question as to whether there’s really some science behind it, which there seems not to be, at least yet.

LAURA:  Right. And like we said, just because there’s no evidence for it doesn’t mean that it doesn’t work. But we hesitate to recommend anything that doesn’t have some level of potential benefit that we can be confident about. Anyway, so did you have anything else to add about food combining or do you think we covered it pretty well?

KELSEY:  I think that was good! We did a good job. I think we covered a lot of different angles and gave you guys some really practical tips that you can go ahead and start using if you want to accomplish the goals of weight loss or better digestion, and doing it in a better way than the food combining diet. So I think, yeah. I think that’s all set!

LAURA:  Great! So if anyone has any questions or any comments that they want to leave in the comments section of this podcast, we’d love to hear some feedback. We also would love to get any other questions that you’d like us to answer. We’re going to be recording these podcasts hopefully on a bi-weekly basis. That’s our goal. So if you have questions you want addressed on the next podcast, then leave them in the comments area and we’ll try to get to them on our next show. So, all right! Well, it was good to talk to you Kelsey, and hope to see everyone around next time for the next edition of Ask the RD.

KELSEY:  All right, take care, Laura.

LAURA:  You too, Kelsey.

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Join the conversation

  1. Hi Ladies, I was always taught in my naturopathy studies that you should not drink liquids with meals because it dilutes the digestive enzymes. I have also found that in most this stops excess gas and bloating. This is even related to avoiding very “watery” fruits with meals. However just recently I have looked into this and can not find any research. In fact there are a few people trying to quash this idea. Stating that in fact it may be useful. Have you found any research to support this theory? If so I would love to read it. See article http://theness.com/neurologicablog/index.php/do-cold-drinks-alter-digestion/

  2. I’ve food combined for years and 100% Paleo for 10 months now. All I can say is, unless you’ve actually tried it, say for 30 days, whether it’s backed by a study or not doesn’t negate it’s validity. These 2 bouncing off everything the other says is appauling and I’d trust neither with my health and wellness. I’m sorry but this seemed more like a food combining witch hunt.
    It makes sense and if done correctly, you feel amazing!! I’ve never lost weight more effortlessly, been healthier or happier and felt like a million bucks as when food combining. Don’t knock it until you’ve tried it. “Eat Great Lose Weight” and “Get Skinny on Fabulous Food” changed my life. Incorporating Paleo into the mix has made it even better.

    • I fully agree with Kristin. I keep seeing article after article about how food combining makes no scientific sense and the benefits of it are myth, but eating according to food combining rules has made me feel so much better regardless.

      I have ulcerative colitis and have had a lot of bleeding and mucus for months as well as occasional gas and cramps. I started food combining and the bleeding was gone after about a week and a half, no mucus by the end of the third. I took a break from the diet and the bleeding and mucus came back as well as gas and abdominal pain.

      There may be no scientific evidence to support it and the process of digestion may suggest it shouldn’t make a difference, but it seems to make a huge difference for me and a lot of other people I know with IBD. Maybe it’s the placebo effect, maybe it’s some biological reason we don’t know about, I don’t know. But it makes me feel good so I’m going to keep doing it!

  3. Loved reading this, but I want to mention that you shouldn’t include a vegan or rather plant based diet as “low palatable,” that’s just very misinformed. I am a vegan and I can honestly say that I have never had such a large variety of foods as well as such delicious foods since going vegan. I enjoy eating now more than ever.
    That is a common misconception because people are used to using animal products to prepare foods and just don’t realize the abundant options and better options even as taste goes.
    I did not enjoy eating vegetables other than salad loaded with ranch prior to going vegan, for example. When at restaurants or eating food prepared by a friend or family and even by myself (as it was the only way I learned to prepare veggies and witnessed veggies prepared), they were always just smothered with butter or cheese… veggies were basically a necessity that needed to be tolerated. Since going vegan I learned how to use spices, prepare various raw salads, use healthy oils (NEVER palm), and so on and they are so savory and delicious… People go crazy over the veggies I prepare. A lot of recipes I fell in love with were from other cultures, like middle eastern cuisine for example. The western world truly does not know how to eat and other parts of the world are much more plant based, and, happen to have the most delicious (and healthy) foods.
    But it’s not just veggies you eat on a plant based diet or being vegan… aside from the countless amazing sandwiches, pastas, and other main courses… vegan junk food is insanely good… It is very possible to not lose weight on a vegan diet due to overeating lol. But people do tend to lose weight when going vegan because our bodies are designed to thrive on plant based diets and there are things about dairy that cause weight gain that aren’t generally accounted for by most dietitians as the meat/dairy/egg industries rein in the western world and we’re in such a bad habit in general of looking at these things for the bit of nutrients they might provide minus the side effects and better sources to obtain said nutrients.
    I do recommend watching Cowspiracy for a look into the dangerously unsustainable factors of consuming animal products. I hear Forks Over Knives is a great one for nutrition factors (if I’m remembering right) which might be interesting for you two as you’re especially educated on nutrition.
    Anyways, just wanted to leave my two cents. Thanks for reading, and thanks so much for this info!

    • Thank you for your response, and I agree! I’m definitely an omnivore, but I agree that veggies and fruits taste soon much better without the weight of sugars and dairy products. By the way, as a teacher (taught all age groups), it’s been quite remarkable to have been able compare the health–especially allergies and asthma–of my milk-drinking students to the nondrinkers. In my experience, with few exceptions, the milk kids tend to definitely be the snotty, asthmatic, allergic, eczema, upset stomach kids. My own personal experience was the same. I am the only one of four girls who suffered no allergies or asthma, and I mostly refused to drink milk as a kid. Anyway, I’d definitely hesitate to discredit eastern practices or to choose any western dietary practices over them. Considering all of the diet-based diseases and ailments for which the west suffers more than most other nations, it is dangerous to consider ourselves more credible.

  4. Hello,
    What would you recommend to drink while eating, without diluting the acidity on the stomach?

  5. My question concerns limiting liquids during meals. Since many supplements need to be taken with a meal, it seems like difficult advice to follow, as downing multiple supplements means I’m drinking several glasses of water. Would soft food therefore be a better carrier than liquid for taking supplements that are to be paired with meals?

    • Hey Lynn,

      I have trouble swallowing pills (especially big ones), so I never take them with just liquid. (I can feel them slipping down my throat and the gag reflex is just too strong.) Usually I take a bite of food, chew a few times, then stick a pill or two in my mouth and swallow the whole lot. That way, it just feels like food going down…can’t feel the pill. That would be one way to reduce the amount of liquid you feel like you “need to” drink just to get the pills down.

      • You also could buy a mortar and pestile to crush your pills into a powder form, which could easily be added to your food or a smoothie. Soft gels can be opened and poured into smoothies as well.

  6. You mentioned in the podcast that drinking too much liquid with meals can overly dilute digestive acids and enzymes and thus impair digestion.

    I’ve also read that liquid in the stomach signals the body to release digestive enzymes, so drinking too little liquid with meals could impair digestion.

    What does research support? If both extremes are problems, then at what point? (I.e., how much liquid is too much, and how much is too little?)

  7. Great podcast. I’ve been experimenting with food combining for digestive issues with some success but I see it only as a band-aid while I heal.

    One thing though – you may have misunderstood some aspects of food combining. Like paleo, there are many different interpretations. I read some sites suggesting that all the macros be eaten in exclusive meals and found it silly. At the suggestion of better informed sources, I combine fat and non-starchy vegetables liberally with all my meals but try to minimize the combinations of concentrated protein with concentrated starch. I eat my steak at one meal and my potatoes at another, but have fat and non-starchy veggies with both. It’s working out well for me.

  8. Great podcast ladies! You are a great addition to this site.

    I would like to second the motion for a podcast on supplement and food timings, maybe combined with probiotics and prebiotics.

    Things like:

    Amino acid supplements (Are they a good idea? Combining, etc)
    When to take digestive and gut barrier support supplements
    Are protein breakfasts important
    Carbs at night (aka carb backloading)
    Fasting, is it always healthy
    Do all probiotics survive, do they make a dent in your current flora
    The best form of prebiotics, resistant starch, etc.
    How and when to use probiotics, should they be combined with resistant starch or other prebiotics.
    Are gluten free oats a good food source to feed healthy bacteria, if you aren’t cross reactive. (Something promoted by the BBC recently).

    Anyway, just some ideas.

  9. I was going to submit this question for the next webinar. Thanks for anticipating the interest. So many of these “diets” seem to contradict physiology and biochemistry, as you point out. As you also note, there is no evidence for them; they are just presented as factual with no substantiation. As a scientist, I find it fascinating that these ideas seem to keep popping up, when they fly in the face of science. It’s just so puzzling that people who accept them don’t ask for supporting evidence. I wonder if more of these “theories” have been developed in recent years, or if they are old ideas are just getting more exposure on the Internet.

  10. Along the same lines as food combiniing, are you abel to do a podcast on the timing of different supplements. Working with a natropath here in Australia he says timing is critical. For supps like ProBiotic I can understand the need to take on an empty stomach. However, the issue of should a supplement be taken x minutes before, during, or x minutes after eating food would be goood to know.

  11. Dr. Wayne Pickering, an advocate of food combining, did an interview with Dr. Mercola last month. http://articles.mercola.com/sites/articles/archive/2013/10/27/food-combining.aspx I’ve never had issues with combining foods (even with gerd that I cured with HCL betaine supplents), so i’m glad to learn from Mark Sisson that I’m not eating improperly. However, it’s hard to dismiss outright as those that have had stomach/intestine/bowel trouble seemed to have found relief with this method of eating.

    • Loved the podcast, very informative, but I have a little suggestion.. Could you maybe work on slowing it down a little? I had to skip back to repeat things pretty often, more so early on; I’m amazed at Laura’s fluency with these topics, but sometimes the fluency speeds up the delivery to the point that it’s hard to comprehend in one pass :/. Nonetheless, I look forward to hearing future podcasts from you two, keep it up!

      Kudos to Chris for recruiting these fresh, youthful promoters of an ancestral diet. As a Nutrition student myself, it’s puts a smile on my face to hear accurate information from impressively knowledgeable students in my age bracket!