Are You Lower-Carb Than You Think? - A Case Study | Chris Kresser

Are You Lower-Carb Than You Think?

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how low is low carb
Fruits like blueberries, are a good option for a low carb diet. istock.com/BrianAJackson

Over the last couple of weeks we’ve been discussing the benefits and risks of low-carb and very low-carb diets. Laura, one of my staff nutritionists, kicked things off with an article called “Is a Low-Carb Diet Ruining Your Health?”, and I followed up with an article called “7 Things Everyone Should Know About Low-Carb Diets”. Then Kelsey, my other staff nutritionist, wrote an article called “The 3-Step Process for Determining Your Ideal Carbohydrate Intake”. In the near future, we’ll be featuring an article about the therapeutic uses for very low-carb and ketogenic diets.

Are you on an “accidental” very low-carb diet? Find out here:

The takeaway from all of these articles is relatively simple and uncontroversial—at least according to anthropological and clinical research:

  • Very low-carb (VLC) and ketogenic diets are useful therapeutic tools in certain conditions.
  • Some (but not all) people experience adverse effects from following VLC and ketogenic diets—especially when done over an extended period of time.
  • Very low-carb diets were extremely rare during the course of our evolution and are not the “default human diet” (as some have claimed).

Before we move on to cover the therapeutic uses of VLC/ketogenic diets, I want to address an issue that I see relatively frequently in my private practice. I’ve begun to think of it as the “accidental low-carb diet” phenomenon. The best way to explain this is to share a case study. 

The Accidental Low-Carb Diet: Frank’s Story

A few months ago I spoke to a patient—we’ll call him Frank. Frank is a 32-year old male who is on the SWAT team in a major metropolitan city. He came to see me complaining of extreme fatigue, insomnia, and exercise intolerance. These issues were obviously of paramount importance given his job.

About a year prior to our first visit Frank had started a low-carb Paleo diet. Some of his colleagues on the SWAT team were doing it with great results, so he figured he’d give it a try. He wanted to lean out and lose about 5 pounds of belly fat that he was having trouble getting rid of. After a few months on the low-carb Paleo diet, Frank did reach his target weight and body composition. 

But then the fatigue and insomnia started. A few months after that, he noticed he was having trouble keeping up with his training routine (which is, as you might imagine given his profession, quite rigorous). 

Frank reads my blog and listens to my podcast, and he had heard me say that some people can experience problems on a very low-carb diets. So he started to add some carbs back into his diet. This helped a little bit, but when he finally set up an appointment with me he was still struggling. 

When I talked to Frank, I asked him how he would characterize his diet. He said he used to do low-carb, but now he was on a moderate carb. I’ve learned over time not to accept this at face value, so I probed further. I asked him specifically how much carbohydrate he eats in the form of starchy plants and fruit (more on this below) on a daily basis. His answer: a sweet potato and about a half a cup of blueberries 3-4 times a week.

Although Frank thought he was on a moderate carbohydrate diet, when we did the math, it became clear he was on a very low-carb diet with fewer than 10% of calories from carbohydrate. Here’s how it breaks down:

  • Frank is 6’3 and 215 pounds (with a lot of muscle). He is extremely active. In order to simply maintain his weight, he would need to eat about 3,000 calories a day.
  • If we define a moderate carbohydrate diet as 25% of calories from carbohydrate, that means Frank would need to eat 750 calories a day as carbohydrate. At 4 calories per gram of carbohydrate, that comes out to about 188 grams of carb each day, or 1,316 per week.
  • A large sweet potato contains 37 grams of carbohydrate. 1/2 cup of blueberries contains about 10.5 grams of carbohydrate. In addition to these amounts of starch and fruit, Frank ate about 3-4 servings of nonstarchy vegetables each day (about 25 grams of carbohydrate on average). Given these numbers, Frank was eating about 365 grams of carbohydrate a week.

At 3,000 calories a day, this works out to about 7% of total calories from carbohydrate. That is most certainly not a moderate carbohydrate diet.

Do Carbs Cause Weight Gain? Frank’s Experience.

When I explained all of this to Frank at our appointment, he was pretty shocked. He was under the impression that eating a few sweet potatoes and some berries throughout the week put him in the “moderate carb” category. Obviously, this was not the case given his weight and activity level.

He was even more shocked when we calculated how much carbohydrate (again, from starchy plants and fruit) he’d have to eat to get to the “moderate” carbohydrate level of 25% of total calories. For Frank, to reach this target of 188 grams per day, he could eat the following:

  • Four servings of nonstarchy vegetables (25 grams)
  • One large Russet potato (64 grams)
  • One cup sliced cooked plantain (48 grams)
  • One medium banana (27 grams)
  • One cup of strawberries, halved (12 grams)
  • One half-cup of blueberries (11 grams)

This meant having a full serving of a starchy plant with two meals, and some fruit either with each meal or between meals—far more carbohydrate than Frank was eating previously.

Frank was initially reluctant to eat this much carbohydrate. He told me that he had noticed that carbs caused him to gain weight. But again, when we I dug a little deeper it became less clear that it was carbohydrate in general that caused weight gain, but a certain kind of carbohydrate (namely, processed and refined carbs). 

Turns out that Frank had very strong cravings for carbohydrate after a while on the VLC diet. Instead of increasing his intake of starchy plants and fruit, he’s stay extremely low-carb and then fall off the wagon by eating bread, pizza, or something like that. Not surprisingly, he would gain weight after these “indiscretions”. (Interestingly enough, he would also feel more energetic and sleep better afterwards.)

I asked Frank whether he gains weight when he eats carbs from whole-food, Paleo-friendly sources like starchy plants and fruit. He said he didn’t know, because he had never tried eating the quantities of these foods that I was recommending. So of course that became our next experiment. 

When I spoke to Frank about ten weeks later, he was ecstatic. His insomnia was completely resolved. His energy levels were not only restored, but higher than they’d been in recent memory. But what he was happiest about was his increased performance at work; Frank had recently placed highly in a national SWAT competition that his team competed in. 

What’s more, he accomplished all of this without gaining a single pound. On the contrary, he had lost a further 3 pounds of fat and was more “lean and ripped” than he had been on the VLC diet. 

If this had been an isolated experience with a single patient, I wouldn’t even bother writing this article. But in fact it’s a fairly common occurrence in my practice. I have every patient I see fill out a diet diary which shows me exactly what they eat on an average day. Then I ask them what their carbohydrate intake is like. I’d say about 50% of the time—if not more—my patients are consuming significantly less carbohydrate than they think they are

If you think you might fall into this category, you can use the guidelines below to calculate your optimal carbohydrate intake. 

How to Calculate Your Carbohydrate Intake

The first important thing to understand is that it’s far more useful to think in terms of of percentage of calories for carbohydrate than it is to think in terms of grams per day. I often hear people make recommendations for the number of grams of carbohydrate someone should eat. But this is meaningless when you don’t take weight and activity level into account. 75 grams a day may be a moderate-carb diet for a sedentary woman eating 1,600 calories a day, but it would be a very low-carb diet for a highly active male eating 3,000 calories a day. 

The table below illustrates the ranges for “very low carb”, “low carb”, “moderate carb”, and “high carb” using percentage of calories for carbohydrate. I’ve also included examples for how many grams of carbohydrate an average, moderately active male and female might consume per day given those ranges, as well as a list of health conditions/goals that might do well for each range.

Carbbohydrate Intake Chart

In order to calculate your exact target range, follow these steps:

  1. Figure out how many calories you should eat per day. This depends on your height, weight, activity level, and goal (weight loss, maintenance, or gain). You can use any number of online calculators to get this information.
  2. Once you have your daily calorie intake, multiply that number by your target percentage of carbohydrate. So, if your daily calorie target is 2,000 calories and your target carb intake is 20%, multiply 2,000 by 0.2.
  3. Once you have the number of calories per day from carbohydrate you need to eat (from step 2 above), divide that by 4 to obtain the number of grams of carbohydrate you should eat. In this example, you’d divide 400 calories by 4 to get 100 grams. That is the number of grams of carbs you need to eat each day.
  4. With this number in mind, you can then consult the charts below, or use online tools like NutritionData.com, to figure out which foods you can eat to meet your goals.

If you’ve never done this before, I’d encourage you to give it a try. If you’re like many of my patients, you might be surprised to learn that you’re eating a lot less carbohydrate than you thought.

Carbohydrate-Content-of-Selected-Starchy-Plants

Carbohydrate-Content-of-Selected-Fruits

Carbohydrate-Content-of-Selected-Nonstarchy-Vegetables

Now I’d like to hear from you. When you calculate your carbohydrate intake as I described above, are you lower-carb than you thought? What was the difference? Have you found that eating more “real food” carbs addresses your carb cravings without causing weight gain or other symptoms? Let us know in the comments section.

206 Comments

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  1. Hello Chris,
    I have a question. I am two days into a re-feed and thought I’d break out my glucose monitor and check my post meal numbers tonight after eating 1/4 c sweet potato and 1/4 white potato with butter, 5 (yes five) cubes of cantelopue, I checked 45 minutes after eating and I was floored to see my glucose at 180!! I am beastfeeding, (3 weeks postpartum) and am no where near the recommendations on the charts above for carbs. I also have hashimotos (take NDT and t3) and adrenal issues, I take my meds at 4 am to boost cortisol production. I noticed I was a bit sleepy after my lunch this afternoon but I always have an energy dip about 3 pm.
    I’m freaking out!! Do I continue the re-feed or do I drop my carbs back down. My glucose dropped to 114 (2hrs) and 93 (3 hrs) post meal tonight.
    Prior to re-feed while doing VLC my FBG was between 80-90. Failed the pregnancy OGTT but charted post meal and FBG for one week and my Dr said it looked fantastic.
    Am I doomed to a life of lettuce and non-starchy veg with the occasional fruit??!!
    Thank you for all the work you do!

  2. Hi Chris,

    I have just come across your website and have subscribed and got your book.
    Two years ago, in addition to working, horse riding and activity 6 days a week, I took up training for triathlon sprints. I was 49 years old, fit and active and slim. I increased my protein, (I have always eaten loads of fruit and veg, am gluten intolerant and clean eating) and cut back on carbohydrates. Wrongly! I ended up with post viral illness and wiped out for 4 months. Two years later, I still wipe out every time I try to build up exercise again. My question and my total shock is that I am the opposite of everyone else on this post! I thought I had upped to moderate carbs but according to your charts I am supersonic high on carbs! So why all my fatigue? Please help?!

    • Can you give us a few details on what you eat to obtain “supersonic” levels of carbs? Sorry for sounding doubtful, but it’s really not easy to eat that many carbs while avoiding grains.

      • Hi Betty, yes I can, thank you for your interest. I have porridge made of water and 2 tablespoons of gluten free oats and 1 oz of raw nuts for breakfast, (and an egg when I’m training),lunch and dinner are piles of non starchy veg and salad plus 4 – 8 oz protein plus a portion of rice/buckwheat, millet or jacket potato or sweet potato or buckwheat pasta or rice and millet noodles. (As in 2oz when dry standard portion) I have a portion of fruit before each meal, 1 oz raw nuts in the afternoon and for snacks I have gluten free buckwheat, oat, chestnut and multigrain crackers with various nut butters. I have 2oz of 100% chocolate after dinner 🙂 So no added sugar or products with sugar in. I need to lose 8lbs to get back to my optimum weight so my grams worked out as 43g per day. This all adds up to about 3 times that! I am grateful for any help you can give me. Thank you, Susi

  3. Nice reading on possible better prognosis of diabetes through modulation of gut microbiota (July 2014)

    Gut microbiota, probiotics and diabetes
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4078018/

    “Diabetes is a condition of multifactorial origin, involving several molecular mechanisms related to the intestinal microbiota for its development. In type 2 diabetes, receptor activation and recognition by microorganisms from the intestinal lumen may trigger inflammatory responses, inducing the phosphorylation of serine residues in insulin receptor substrate-1, reducing insulin sensitivity. In type 1 diabetes, the lowered expression of adhesion proteins within the intestinal epithelium favours a greater immune response that may result in destruction of pancreatic β cells by CD8+ T-lymphocytes, and increased expression of interleukin-17, related to autoimmunity. Research in animal models and humans has hypothesized whether the administration of probiotics may improve the prognosis of diabetes through modulation of gut microbiota. We have shown in this review that a large body of evidence suggests probiotics reduce the inflammatory response and oxidative stress, as well as increase the expression of adhesion proteins within the intestinal epithelium, reducing intestinal permeability. Such effects increase insulin sensitivity and reduce autoimmune response. However, further investigations are required to clarify whether the administration of probiotics can be efficiently used for the prevention and management of diabetes.”

  4. Hi there.
    Could anyone please help out with my query:
    In the book “Paleo Code” it says you shouldn’t count non starchy plants to your total carb intake but in Frank’s case study they were counted towards the daily carb intake.

    Question: Should you count non starchy veggies towards your total daily carb intake or not?
    Thank you, Nina

  5. Hi. Thanks for the great article. It really made me think about revamping my family’s diet. My three year old daughter is currently losing hair. Her medical practitioner said that with multivitamin with iron might resolve the issue. But after a month of consistency with that not much improvement. My 11 son struggles with anxiety. My husband is wanting to lose weight and I am wanting to increase my muscle and decrease my bodyfat percentile. I hope to try calculating our calorie intake/amount of carbs from Paleo friendly sources like you suggest and seeing if I see any improvements in my children’s moods, energy levels and overall health. They both struggle with allergies/asthma symptoms and my husband does as well. Getting over colds usually takes a long time and for my son it leads to the prescription of Pulmicort or something similar to get rid of the wheezy cough afterwards.

    I realize that we eat fairly healthy at home- lean meats, cage free/organic eggs, healthy fats like olive oil, nut butters and coconut oil, but overall we hardly any veggies and minimal fruits, especially the three year old who is picky about textures.

    Thanks again for the info. I will post our results in a few months.

  6. I have been eating very low carb for about a month. I don’t believe I have ever made it to ketosis due to the amount of protein I eat, though I have been eating less food. The hunger and cravings are normalized (I eat only after 5 hours to help the leptin signal) and yet I have not lost a single pound! That seems to be the biggest concern…..gaining back weight after getting to the point where I actually tolerate less carbs. I believe I need fruit, for better health, but my chiro is warning me off for now. Maybe some blueberries. I am a lousy calorie/carb counter, but I am great at following a way of eating like a religion, having been a former raw vegan. That was the least health ever, with the biggest problem being related to mental health. So I do read your blog with interest (and have recently bought bacon made the regular way) but sometimes I am not sure if it’s gonna work for me….I do have blood sugar issues, etc. Feedback welcome….and plantains actually sound very inviting!!

  7. Hi Chris – great article, I really appreciate your post. I’ve lost 43 pounds on low carb, and my goal is 50…I’m so close, but I swear some days it feels so far away. I’m trying to get out of a rugged plateau I’ve hit, and making sure I’m still doing low carb “right” – it was soooo effortless a year ago.

    Just a quick question about your method for calculating ideal carb intake: I typically don’t count dietary fiber (I only count net carbs), but I noticed that you do not in your breakdown you gave to frank. The calculation I did recommends 51 g of carbs per day, but does that include dietary fiber? If so, I need to change my eating habits completely.

    Thank you so much.

  8. Why does it have to be low carb high fat? How about lower carb, moderate fat, with the fat leaning towards mono as opposed to saturated.
    Seems like people want a specific formula, and when it doesn’t work they throw out the baby with the bath water. I too experienced elevated LDL-P, and switched to more a more mono fat profile.
    My current readings: LDL-89. HDL-65. TC-168. And LPL-P dropped from 1900 to 1250.
    I really think it would benefit many to cut back on the sat fat. Just because it’s not bad, doesn’t make it good.

  9. I’ve been exploring this and the level of my carb intake after reading The Perfect Diet. After working with Jordan and Steve for a few years – and getting my SIBO managed – I have found I still can’t do resistant carbs – and the SCD legal/illegal list still is helpful for me since any carbs that aren’t monosaccharides flair my SIBO. Is it ok to increase the carbs without resorting to the resitant starches? I know it’s less than ideal – but my poor cleansing waves in my small intestine just don’t keep the over growth under control. If my carbs rise above a certain point (I do fine with low starch veggies and low sugar fruits) but it’s hard then to keep my carb count high enough. My energy is ok – but I do notice some sleep issues without having more carbs. Thanks for the post – will keep tracking!

    • Instead of avoiding triggers, have you considered trying to cure the disease? Check out the American Gut Project. They do gut flora analyses. Maybe you’re a candidate for a fecal transplant. Sure, it sounds nasty, but if it cures everything and your intolerances disappear isn’t it worth it?

  10. Hi Chris and all , reading the article I had an”aha! ” moment – finally it looks clear to me what I was doing wrong and now it easy to count carbs . Reading all comments ….I am confused again , since many people have same Q and issues what I have and it looks now I am lost again 🙁 having sugar problems and at the same time being low on carbs but my weight growing and fatigue is more but I don’t have any cravings anymore etc. etc. lost completely !!!

    • Ditto to this comment by Anna! Lost too. Not sure how or whether advisable to add in carbs with blood sugar issues..

  11. Good article, I think that the ‘high carb’ version is still quite low in some instances. For weight/muscle gain I think more carbs are needed, I’m currently eating 400g a day and my weight isn’t increasing. I will soon be increasing it to 450 and then 500 (total cals being ~4000).

    Would the fibre in carbs count as carbs or not? I’ve read differing opinions on this with some sources stating that these fats are turned into fatty acids in the intestines anyways? So if my net carbs were 400 but 50g was fibre would this mean my total carbs were 400 or 350?

    My goal is peak performance whilst minimising bodyfat gain.

  12. I’ve been LC or VCL for about 10 years with some wagon fall off’s. Lately with crossfit I’ve tried adding back in carbs to perform better. I’ve not had luck with this. When I add back in sweet potatoes and fruit I get very gassy and have some stomach discomfort. I can’t seem to get past that though and end up cutting carbs back again

  13. Its funny that I got this email in my inbox today. The past week or so I noticed that I had BO pretty badly. earlier today it finally dawned on me that I was probably in ketosis. Purely by accident. Ive been eating lots of non starchy vegetables, that have been in my css box and just meats. Ive been very tired and have 20lbs that I haven’t been able to lose. I just ate big sweet potato and I have some rice soaking for tomorrow. Thanks the timing of this article was perfect!

  14. I’m confused by this. According to your math, I should be eating 38 grams of carbs per day to lose weight. But how can I do that and still eat veggies? It seems unrealistic for me to eat this low to lose weight without eating a lot less veg in my diet. Am I missing something?

    • If you want to lose weight, you simply need a calorie deficit. A great way to perform this is to consume less “energy” calories. Fat and carbohydrate are both “energy” calories. Simply put, eat a lot more protein and less of everything else. Don’t look at carbohydrate. Consume lots of lean meats, infinite vegetables, 2-3 servings of fruit or starch a day and really scale back on the fats and oils. Bake, roast, braise, pressure cook – these things cook meats and vegetable gently without adding fats and oils and produce a delicious product with the lowest potential for carcinogens you get when you sear, grill and fry.

    • YES – it did to mine – Thomas Dayspring did a really interesting post on a case study, and Paul Jaminet has a number of posts on low carb diets and very high LDL. Mine went to 285. I added more carbs, took out all added sources of saturated fat (coconut, butter, cream, and trimmed meat fat) used monounsaturated fats in small amounts, increased the anti-oxidant foods in my diet like kiwi, berries and veg. added a cup of starchy veg or berries to my meals. It is back down to about 150 now.

  15. I’ve never understood the fascination of carbs in the paleo movement. All of the time I hear folks concerned about their carb intake, but rarely ever their fat intake. The human body preferentially stores dietary fat as body fat, not carbohydrate. Carbohydrate intake merely halts free fatty acid mobilization. It is dietary fat that is stored as body fat in times of caloric excess. The moral of the story is that if you overconsume calories you will gain weight. In fact, if calorie and protein content of your diet is equivalent, you will probably lean out better getting more of your “energy calories” from carbs rather than fats. (Nevermind the fact that carbohydrate increases cellular respiration more than fat, so your metabolism will probably be a little bit faster preferring carbs to fats.)

    The chart in this article states 30% calories from carbs is a “high carbohydrate diet,” yet I’d venture most would say 30% calories from fats is a “low fat diet.” The fact that this stuff matters shows the failure of the paleo movement as a whole. The focus should simply be eating real food, folks. Be it potatoes, steak, avocados or bananas, if you can grow it yourself, pick it yourself or kill it yourself, it’s probably good to eat. Chris is a breath of fresh air because he’s more about embracing real food as a whole instead of creating charts and graphs and curves to adhere to that require the purchasing of books.

    • You obviously don’t have diabetes. While I agree with your statement to eat real foods, I personally am only able to keep my blood sugars in the normal range by incorporating a low carb, moderate fat diet.
      I guess I could eat higher carbs and just shoot insulin to cover it? Think I’ll pass.

      • I think you are missing my point, Bill. Diabetes is a condition where your body has trouble controlling the insulin response to carbohydrate. In no way, shape or form, is Diabetes caused by consuming carbohydrate. That would be like leaving your headlights on your car on overnight, waking up to a dead battery, then blaming the battery for being faulty.

        You also seem to think Diabetes is a permanent condition. Low carbohydrate dieting is useful for controlling blood sugar levels, but with that comes insulin resistance. If you’re not eating carbs maybe it doesn’t matter to you if you’re insulin resistant, but if you want to be healthy and insulin sensitive again, you’re eventually going to have to up your carb intake. I would suggest getting an analysis of your gut flora from American Gut Project, limiting your PUFA intake substantially and look into getting your gut very healthy via soil-based probiotics and low GI soluble fiber that you can handle. Over time, if you get healthy again, you should be able to gradually up your carb intake and regain your insulin sensitivity and beat the disease.

        IMO low carb diets have their place, but temporarily. In very few cases should they be completely permanent.

        • First of all there are many different types of diabetes, and one shouldn’t make a blanket statement. In my case I am insulin deficient, my Pancreas does not produce sufficient insulin to cover my food intake. This is genetic as it runs in my family.
          I am not insulin resistant. I am very active and in good shape, well muscled.
          I have a choice of either going down the road of ever increasing anti diabetic medications, or a diet that moderates my carb intake to keep my blood sugars in control. I choose the latter and it has been very effective for me.
          We are al different, just read through these blog posts to verify that.
          And there are many different types of diabetes. You seem well intentioned, but making a blanket statement about a desease as complicated as diabetes does a disservice to the many people struggling with this.
          Hopefully in the near future Chris will address this subset of individuals with specific challenges that are helped through carb restriction.

    • I completely agree – I led a paleo seminar to a group last night – many of whom are following a high fat paleo diet and are overweight and not losing it. Whilst some people lose weight on very low carb high fat diet – that is not the case for everyone.

      • Why does it have to be low carb high fat? How about lower carb, moderate fat, with the fat leaning towards mono as opposed to saturated.
        Seems like people want a specific formula, and when it doesn’t work they throw out the baby with the bath water. I too experienced elevated LDL-P, and switched to more a more mono fat profile.
        My current readings: LDL-89. HDL-65. TC-168. And LPL-P dropped from 1900 to 1250.
        I really think it would benefit many to cut back on the sat fat. Just because it’s not bad, doesn’t make it good.

        • My point exactly – paleo does not have to be low carb high fat (usually high saturated fat) In my view paleo should be a plant based diet with adequate protein. Every time I do high fat low carb, I put on weight, and my appetite control is worse – no to mention my cholesterol. I add very little fat to meals, if I do it is mono.

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