The Top 3 Dietary Causes of Obesity & Diabetes | Chris Kresser
HCTP Banner

The Top 3 Dietary Causes of Obesity & Diabetes

by

Last updated on

iStock.com/pamela_d_mcadams

So far in this series on diabesity and metabolic syndrome, we’ve focused on a new way of understanding diabesity as an autoimmune, inflammatory disorder, and we’ve looked in a general way at the underlying mechanisms (inflammation, genetics, environmental triggers and leaky gut) that contribute to diabesity.

Now that we’ve laid that foundation, we’re going to take a closer look at some of those mechanisms. In this article, we’ll discuss the three major dietary toxins that trigger diabesity:

  • Cereal grains (especially refined flour)
  • Omega-6 industrial seed oils (corn, cottonseed, safflower, soybean, etc.)
  • Fructose (especially high-fructose corn syrup)

At the simplest level, a toxin is something capable of causing disease or damaging tissue when it enters the body. When most people hear the word “toxin”, they think of chemicals like pesticides, heavy metals or other industrial pollutants. But even beneficial nutrients like water, which are necessary to sustain life, are toxic at high doses.

In the Perfect Health Diet, Paul & Shou-Ching Jaminet apply the economic principle of declining marginal benefits to toxins:

It implies that the first bit eaten of any toxin has low toxicity. Each additional bit is slightly more toxic than the bit before. At higher doses, the toxicity of each bit continues to increase, so that the toxin is increasingly poisonous.

This is important to understand as we discuss the role of each of the dietary toxins listed above in contributing to diabesity. Most of you won’t develop diabesity by eating a small amount of fructose, cereal grains and even industrial seed oils. But if you eat those nutrients (or rather anti-nutrients) in excessive quantities, your risk of diabesity rises significantly. This is especially true if you have any of the genes that predispose you to diabetes and obesity.

The primary effect toxins have on the body – whether dietary or otherwise – is inflammation. And since we now know that diabesity is an autoimmune, inflammatory disease, it’s clear that anything that causes inflammation is a potential risk factor for both diabetes and obesity.

The impact of each of these dietary toxins could fill a book. And in fact, there are several such books and many other blogs that have covered this material in detail. Rather than re-create the wheel, I’m going to provide a brief summary and then link you to resources if you want more detail.

Cereal Grains: The Unhealthiest “Health Food” on the Planet?

The major cereal grains – wheat, corn, rice, barley, sorghum, oats, rye and millet – have become the staple crops of the modern human diet. They’ve also become the “poster children” of the low-fat, high-carbohydrate diet promoted by organizations like the American Heart Association (AHA) and American Diabetes Association (ADA).

If you say the phrase “whole grains” to most people, the first word that probably comes to their mind is “healthy”.

But the fact is that most animals, including our closest relative (the chimpanzee) aren’t adapted to eating cereal grains and don’t eat them in large quantities. And humans have only been eating them for the past 10,000 years (a tiny blip of time on the scale of evolution). Why?

Because plants like cereal grains are always competing against predators (like us) for survival. Unlike animals, plants can’t run away from us when we decide to eat them. They had to evolve other mechanisms for protecting themselves. These include:

  • producing toxins that damage the lining of the gut;
  • producing toxins that bind essential minerals, making them unavailable to the body; and,
  • producing toxins that inhibit digestion and absorption of other essential nutrients, including protein.

One of these toxic compounds is the protein gluten, which is present in wheat and many of the other most commonly eaten cereal grains. In short, gluten damages the intestine and makes it leaky. As we saw in the last article, a leaky gut is one of the major predisposing factors for diabetes and obesity.

Celiac disease – a condition of severe gluten intolerance – has been well known for decades. These people have a dramatic and, in some cases, potentially fatal immune response to even the smallest amounts of gluten. However, what is less well known is that wheat gluten triggers an immune response and gut inflammation in almost everyone – regardless of whether they are “gluten intolerant” or not. Over 80% of the population develops measurable gut inflammation after eating wheat gluten.

Dr. Kurt Harris, author of one of my favorite blogs (PaleoNu), calls wheat one of the three “neolithic agents of disease” (we agree on the other two as well). For more information on the toxic effect of cereal grains, see Dr. Harris’s two articles “The argument against cereal grains” and “The argument against cereal grains, part II”.

Industrial Seed Oils: Unnatural and Unfit for Human Consumption

Industrial seed oils (corn, cottonseed, soybean, safflower, sunflower, etc.) have not been a part of the human diet up until relatively recently, when misguided groups like the AHA and the ADA started promoting them as “heart-healthy” alternatives to saturated fat.

The graph below shows how dramatically seed oil consumption has risen over the past several decades:

pufaconsumption

Industrial seed oils are extremely harmful when consumed in excess. I’ve written about this at length in my series on essential fatty acids. In the context of this article, researchers have shown that industrial seed oils have played a significant role in the current obesity epidemic.

A recent study showed that a diet with an omega-6:3 ratio of 28 (meaning 28 times more omega-6 than omega-3 fats) caused obesity that progressively increased over four generations of mice. This means that eating too much omega-6 didn’t only cause obesity in the current generation, but it also predisposed future generations eating the same diet to developing obesity.

This is bad news for those eating a Standard American Diet, which contains an omega-6:3 ratio that is very similar to what the mice in the study above were fed.

Omega-6 seed oils have also been shown to cause inflammation, insulin resistance and impaired leptin signaling, all of which directly contribute to diabetes.

Finally, industrial seed oils have been shown to interfere with thyroid function by blocking the binding of thyroid hormone to its receptors. The result is a higher fat mass and a less efficient metabolism.

For more information on how seed oils contribute to diabesity, see The Body Fat Setpoint, Part III: Dietary Causes of Obesity, Have Seed Oils Caused a Multi-Generational Obesity Epidemic?, and my series on Essential Fatty Acids.

Fructose: The Sweetest Way to Get Diabesity

White table sugar is composed of two sugars: glucose and fructose. Glucose is an important nutrient in our bodies and is healthy, as long as it’s consumed in moderation. Fructose is a different story.

Fructose is found primarily in fruits and vegetables, and sweeteners like sugar and high-fructose corn syrup (HFCS). A recent USDA report found that the average American eats 152 pounds of sugar each year, including almost 64 pounds of HFCS.

Unlike glucose, which is rapidly absorbed into the bloodstream and taken up by the cells, fructose is shunted directly to the liver where it is converted to fat.

Excess fructose consumption causes a condition called non-alcoholic fatty liver disease (NAFLD), which is directly linked to both diabetes and obesity.

A 2009 study showed that shifting 25% of dietary calories from glucose to fructose caused a 4-fold increase in abdominal fat. Abdominal fat is an independent predictor of insulin sensitivity, impaired glucose tolerance, high blood pressure and high cholesterol and triglycerides.

In a widely popular talk on YouTube, Dr. Robert H. Lustig explains that fructose has all of the qualities of a poison. It causes damage, provides no benefit and is sent directly to the liver to be detoxified so that it doesn’t harm the body.

Another danger of fructose is that it reacts with polyunsaturated fats and proteins to form toxic compounds called Advanced Glycation End-Products (AGEs) in a process known as “fructation”. (Who comes up with these words?) AGEs wreak all kinds of havoc on the body; they damage DNA, speed up the aging process and cause high blood pressure and kidney disease. And studies have shown that fructose is up to 10 times more likely to produce AGEs than glucose.

For more on the toxic effects of fructose, see The Perfect Health Diet and Robert Lustig’s YouTube talk: Sugar, The Bitter Truth.

A Toxin-Free Diet Prevents and Even Reverses Diabetes

In addition to all of the evidence above, we have two other lines of evidence that strongly indicate that cereal grains, seed oils and fructose contribute to diabesity.

First, diabesity is either non-existent or extremely rare in hunter-gatherer cultures that don’t consume these toxic foods.

Second, two studies have shown that a paleolithic diet (free of cereal grains, seed oils and excessive fructose) produced dramatic improvements in cardiovascular and metabolic markers.

The first study, performed by Dr. Staffan Lindeberg and colleagues, found that a paleolithic diet was superior to the mediterranean diet in several ways. These are summarized in Stephan Guyenet’s article on Lindeberg’s study:

  • Greater fat loss in the the midsection and a trend toward greater weight loss
  • Greater voluntary reduction in caloric intake (total intake paleo= 1,344 kcal; Med= 1,795)
  • A remarkable improvement in glucose tolerance that did not occur significantly in the Mediterranean group
  • A decrease in fasting glucose
  • An increase in insulin sensitivity (HOMA-IR)

The most remarkable outcome of the study is that, although 12 of 14 participants had elevated fasting blood sugar at the beginning of the trial, every single participant had normal fasting blood sugar at the end of the trial.

Dr. Lindeberg published a follow-up study in 2009. In this case they compared a paleolithic diet with a conventional ADA low-fat “diabetes diet”. While the results weren’t quite as impressive as the first one, they were still very encouraging. Participants in the paleolithic group:

  • Reduced HbA1c more than the diabetes diet (a measure of average blood glucose)
  • Reduced weight, BMI and waist circumference more than the diabetes diet
  • Lowered blood pressure more than the diabetes diet
  • Reduced triglycerides more than the diabetes diet
  • Increased HDL more than the diabetes diet

At the end of the trial, 8 out of 13 patents still had diabetic blood glucose levels. However, in this study the patients had well-established diabetes for an average of 9 years. Over time diabetes progresses to beta cell destruction, which reduces insulin output. Once this point has been reached, dietary changes can be helpful but cannot completely reverse diabetes.

What this means, of course, is that the earlier you remove these toxins from your diet, the better chance you have of preventing and even reversing diabesity. And while a paleolithic diet may not reverse diabetes in those that have had it for several years, it still produces significant improvements.

** A donut is the perfect diabesity food. It’s got refined flour (cereal grains), industrial seed oils (plus trans fats for an added bonus), and plenty of high-fructose corn syrup.

  1. Hi Chris,
    I would love to know what effect fruit has on the body, is it still considered dangerous in large amounts? I am asking because my sons love fruit and some days my eldest (4) will eat up to 6 pieces. Am i putting him in danger of non alcohol related fatty liver or type 2 diabetes, is all that fructose wreaking havoc on his little body?
    I would very much appreciate an answer as i am worried i could be harming him. Thankyou

    • Do not worry, at all. In fact, encourage him to eat more fruit. Humans are high-carbohydrate individuals, and we need healthy carbs like fruit to function and acquire vitamins. This article’s flaw is that it mixed up high-fructose corn syrup with fructose from fruit. The fructose one gets from most fruit is slowly released in the body, and it had a low Glycemic Index. Eating fruits and vegetables are actually better for the pancreas than eating red meats or chicken, which are some of the main causes of western society is developing so much diabetes.
      If you really are worried about your kid, stop feeding him dairy and red meat. Optimally, a vegan diet is recommended, but not everyone is comfortable with that. Fish and hormone-free chickens are much better when it comes to building life.

      • Less milk and red meat? Theres essential amino acids in milk and red meat – essential meaning our bodies cannot produce it by re-arranging various amino acid molecules to make EAA’s. And also, theres no such thing as essential carbs.

        • Not that they are as well balanced to promote growth, plants have all the amino acids that milk has. The amount of protein in cow’s milk is appropriate for a calf. A lower intake of protein is appropriate for longer living species like humans. Carbs from whole plant-based foods are an excellent way to get clean calories, unlike fats when tend to come with problematic toxins.

      • You have to read in the context of his other work and he has stated clearly elsewhere that fruit is healthy. But yeah, could have made that more clear in this article.

    • Really good article Chris, It’s still about real food, when you eat a fruit you eat fructose together with glucose, fibers, vitamins etc, in the right amount for its volume, but as soon as you eat refined and processed stuff you’re gonna loose such proper nutrient/volume ratio and this lead to have much more fructose, more than what your body can deal. And you’re also activating the craving effect, wreaking a big havoc on your body.

    • Chris has written elsewhere that fruit is healthy and has said that our ancestors were eating fruit even before they were recognizably human, so we are well adapted to it. Fructose is only bad in the high concentrations you get it in refined sugar granules and stuff. In fruit, it is relatively low levels and mixed with fibre.

  2. “Cereal grains: the unhealthiest “health food” on the planet?
    The major cereal grains – wheat, corn, rice, barley, sorghum, oats, rye and millet – have become the staple crops of the modern human diet.” Quackery if they are unhealthy so why Japan Taiwan Hong Kong Itally France are heathiest nations and Japan Taiwan Hong Kong also the highest IQ and in this countriest they eat? White rice (in japan also soy in miso soup daily) Italy pasta in france high bread.

    • I’m italian and I only see sickness around me. It’s the homeland of pasta and pizza and you can see the evidence every day. I’m a personal trainer and evo diet educator and so far I’ve only seen improvements in people who get rid of the old habits and turn to evo diet, and I can ensure that the brain improves so much as well.

      • Alessio what a nonsense you wrote? I also been some time in Italy (I’m neurologist toxicologist) and do some studies in your country. “. It’s the homeland of pasta and pizza ” pizza has a low glycemic index what mean that glucose is released slowly the same pasta when you eat with sauce, “I’m Italian and I only see sickness around me.” aha maybe look at epidemiological studies? Italian not only live longer but also have more years of good health before disease and disability set in what is miracle if they even few steps to shops must use cars, What about Japan who also eats far more cars than you? Also, what about other habits? like drinking and smoking and sugar? your country love cakes and other sugar stuffs low activity. “but as soon as you eat refined and processed stuff you’re gonna loose such proper nutrient/volume ratio and this lead to have much more fructose,” you say that refined carbs increase fructose consumption? really?(also Japanese eat mostly white rice and dont have problem with nutrient/volume ratio) you get any education in this field?

        • We won’t get anywhere as long as we go on with talking about glycemix index, protein carbs etc, we have to consider food overall. If you look at one part also a poisonous mushroom can be a good food. Epidemiological studies most times do not provide causation, and studies about italian and japanese, the china study etc are good examples of that lack of causation.

        • High refined corn syrup is a good example of fructose concentration, juices etc..
          Rice is starchy and gliadin free, thus if you don’t overeat it after all it doesn’t do the same mess as pasta, pizza etc…if you consider that people live longer in Sardegna where people eat less refined and gluten stuff, they mostly are ancient shepherds, and Okinawa dwellers don’t eat a bunch of grains, but fish etc, and moreover hunter gatherers are far healthier and stronger than any other civilized populations, you can a more evidence based bias free idea about the issue.

          • “We won’t get anywhere as long as we go on with talking about glycemix index” my mistake I was thinking that this article is about blood sugar, backing to your topic the dose make poison and many plant foods also contain substance that are toxic for example cyanide (of course everything is toxic in some dose). “Epidemiological studies most times do not provide causation, and studies about italian and japanese,” please stop embarrass yourself more, you cannot provide causation in topic if something cause diseases, you claim that studies which clearly show that people eating pasta and have high life expectancy and low ratio of diseases or Japan where 99% eat rice and the same causation is false? maybe check how to understand studies? “High refined corn syrup is a good example of fructose concentration, juices etc..” aha you claim you educate about evo diet? you know that hooney is high in fructose and it is part of this diet? “Rice is starchy and gliadin free, thus if you don’t overeat it after all it doesn’t do the same mess as pasta, pizza etc” rice is carbs giliadin free but contains other proteins (do you have even basic knowledge in topic you wrote?)…”if you consider that people live longer in Sardegna where people eat less refined and gluten stuff, they mostly are ancient shepherds, and Okinawa dwellers don’t eat a bunch of grains, but fish etc” you clearly dont have any idea how studies work, you say that if I look at people who eat high amount of substance and dont cause any toxicity to them then I cant proof causation? Sardegna they eat many foods vegs which contains similiar protein to this in wheat (to protect themself from bugs), about Okinawa you spread incompetence check Okinawa Food Pyramid then you will see that they diet also contain high amounts of carbs from whole grains rice etc, here you only show your incompetence (belive me as a part of my job I was in Itally and Japan many times so I know also about Okinawa diet from first hand).

            • Maybe you’ve been in Itally as you told 🙂 there’s no need to comment anymore when people start to offend the others instead of point out their ideas. Maybe it’s better to learn how to write properly as first thing

              • ” “anymore when people start to offend the others instead of point out their ideas” pointing you incompetence in this field you call offending? ” Maybe it’s better to learn how to write properly as first thing” maybe I start english recently? (I only know english for reading studies but never need for anything else that is why I start learn other languages which I need) So yes maybe I have problem with grammar but at least I have basic knowledgie in field I wrote what I cant say about you. About offending sorry but if you wrote such nonsense about Okinawa diet and don’t even look at google to confirm that, so how can I call you? Saying about causation in a situation where clearly is flawed assumption, when someone thing that gladdins are only one protein with this properties.

              • Really wikipedia is your source? If you will read closely then you will see that they eat everything less (caloric restriction but ratio still remain the same). http://www.easyvigour.net.nz/diettoxin/pokinawaprmd.gif

                “And I’ve never said that gliadin is the only protein..” aha “Rice is starchy and gliadin free, thus if you don’t overeat it after all it doesn’t do the same mess as pasta, pizza etc” buy you say its onlt which matter.
                “But most probably you’re just a troll..” you wrote to me… and at the end showing only incompetence.

  3. I was recently diagnosed with gestational diabetes. I have always had a problem with sugar and grains, so have avoided them. I was shocked when all of the diabetes “experts” I was sent to literally spent hours trying to convince me that if I did not eat grains, breads, and pasta, I was starving my baby. They wanted me to eat 175 grams per day of these refined carbs and then give me insulin, although on my current diet, my blood sugars are well under control. They also tell me that any ketones they find in my blood are toxic for the baby. I have put my foot down, but I have never felt so pressured in my life! It has been a very stressful experience. ANyone else have experience with gestational diabetes and eating paleo? THX

    • My wife did. Eat too low carb and your body makes up for it with GD. See Chris’ post on carb requirements. I’m pretty sure he recommends somewhere around 175g for pregnant/breastfeeding. Just get it from white rice and potatoes

    • Carry, indeed hunter gatherers’s children are starving and we sapiens have been starving until grains have not been introduced in our diet. God or Nature is really stupid not to have considered this…gestational diabetes is the alarm that says that you’re going to an actual and irreversible diabete in some years, get rid of those nonsense and embrace the evidence of Nature

      • “We won’t get anywhere as long as we go on with talking about glycemix index” my mistake I was thinking that this article is about blood sugar, backing to your topic the dose make poison and many plant foods also contain substance that are toxic for example cyanide (of course everything is toxic in some dose). “Epidemiological studies most times do not provide causation, and studies about italian and japanese,” please stop embarrass yourself more, you cannot provide causation in topic if something cause diseases, you claim that studies which clearly show that people eating pasta and have high life expectancy and low ratio of diseases or Japan where 99% eat rice and the same causation is false? maybe check how to understand studies? “High refined corn syrup is a good example of fructose concentration, juices etc..” aha you claim you educate about evo diet? you know that hooney is high in fructose and it is part of this diet? “Rice is starchy and gliadin free, thus if you don’t overeat it after all it doesn’t do the same mess as pasta, pizza etc” rice is carbs giliadin free but contains other proteins (do you have even basic knowledge in topic you wrote?)…”if you consider that people live longer in Sardegna where people eat less refined and gluten stuff, they mostly are ancient shepherds, and Okinawa dwellers don’t eat a bunch of grains, but fish etc” you clearly dont have any idea how studies work, you say that if I look at people who eat high amount of substance and dont cause any toxicity to them then I cant proof causation? Sardegna they eat many foods vegs which contains similiar protein to this in wheat (to protect themself from bugs), about Okinawa you spread incompetence check Okinawa Food Pyramid then you will see that they diet also contain high amounts of carbs from whole grains rice etc, here you only show your incompetence (belive me as a part of my job I was in Itally and Japan many times so I know also about Okinawa diet from first hand).

  4. Hi Chris!~

    I love your articles. I am a holistic dietitian myself who specializes in diabetes. This may be a silly question but do you consider quinoa to be a cereal grain that would contribute to diabetes??

    Kindly,

    Kerry Potter

  5. Chris,

    I love your blog and I find myself reading it often. However, you stated: “Over 80% of the population develops measurable gut inflammation after eating wheat gluten.” I don’t think it’s accurate to extrapolate that conclusion from a very tiny study of such a small group of people to the entire population. Also, the non-celiac people in this particular study had strong symptoms of gluten sensitivity, whereas most of the population does not experience any symptoms.

    I’m suspecting, however, that a large amount of the population probably does have an immune response to gluten, but your extrapolation from that very tiny study is not logically justified. Have there been any studies done since that one that involve larger groups of people? I’d be extremely interested to read them.

  6. While I agree with much of the sentiment. I’m not really sure you understand evolutionary theory. Best to just stick to a ‘Hey, this is healthful!’ type of argument.

  7. Dear Chris,

    I am hoping that you can help me. I have maintained a diet with no white flour or sugar for over 20 years, good oils and fats, fruit limited to occasional berries, and very limited carbs (from vegetables, legumes, and an occasional sweet potato). Although I was 10 pounds overweight and frustrated, I realized that there was something not working properly in my body when I gained 17 additional pounds in a calendar year. I was just diagnosed with insulin resistance and was put on Metformin as my only option to re-sensitize receptors with cream testosterone and DHEA as well. The medicine or testosterone or other imbalance has me really retaining water as well.

    I am willing to test any theories if you have not already researched this particular case. I would like to be able to help people with what we learn.

    I have just started seeing an acupuncturist who is fantastic. He has seen me twice and says that I am very healthy but he can tell how I am out of balance and believe under the layers, it may be hormonal.

    Gratitude and Blessings,

    Shawna

  8. The fat issue is important and was a missing key for a long time.

    So many of us diabetics went low-carb in the 80s and 90s to control bg. Almost by definition, a low-carb diet is high fat, and we ate “healthy” fats – corn oil, soy oil, canola oil, margarine. Thus we found diabetes progressed in spite of low carbing.

    It probably progressed faster for those of us doing the bad fat thing than those who weren’t even TRYING to eat healthy.

    (The diabetics who followed the opposite advice, to eat low-fat diets, progressed even faster with their “whole grains”.)

    I have found my insulin needs decreased on a diet with protein primarily from pasture-raised meat, eggs and raw dairy (and to a lesser extent, nuts & seeds and their butters) and fat primarily from pasture-raised butter, coconut oil, olive oil and avocado oil. (I also supplement fish oil cause I don’t eat much fish).

    I theorize this not only is due to inflammation, but also because cell receptors are made out of lipids, and a diet with almost no saturated fat and heavy on the omega-6s makes for deformed cell receptors, and hence insulin resistance and thyroid resistance, etc. If I’m correct, I expect my insulin needs will continue to decrease for several years as my body rebuilds from the appropriate components.

    BTW, the season matters with butter. A local dairy makes butter with no ingredients but cream and salt, so the color varies. When the grass is growing fastest, the butter takes on a very rich dark yellow color. And I buy 40 lbs of that stuff for the freezer! Chockful of vitamins A, D3 and K2! Good stuff.

    Also, yummy fats make it easy to increase produce intake too. A giant salad topped with olive oil and red wine vinegar, multicolored bell peppers and onions stirfried in avocado oil finished with lime juice, meat and vegetables curried in coconut milk, broccoli with raw cheddar melted over it, avocados dipped in butter, berries floating in heavy cream… in this house, we’d never get through all the CSA veggies without good fats!

    • I think you have it just right…I’m gluten intolerant or celiac… Diabetics runs in my family as well. I’m struggling with my diet. Any advice ?