Are Your Food Allergies Making You Fat? 3 Steps to Weight Loss and Good Health

Mark Hyman, M.D. by Mark Hyman, M.D. | February 23rd, 2010 | 10 Comments
topic: Detox, Health & Wellness, Healthy Aging, Healthy Eating, Weight Loss

Your digestive system might be making you fat. It’s hard to believe, but very true!

Today, I’m going to explain how the bugs in your digestive tract and the way they upset your gut’s immune system just might be behind those extra pounds. I have observed this in hundreds of patients. Remarkable new research has recently confirmed this phenomenon. I have developed very effective treatments for it, based on understanding the way in which all the body’s systems – the gut, the immune system, detoxification system, hormones and more – are connected.

There’s powerful evidence that addressing these key causes of weight gain and illness can help you shed pounds. For example, I’ve seen patients who lose significant amounts of weight just by cutting food allergens from their diet. And, I have also seen people lose 20 to 30 pounds simply by balancing the bacterial ecosystem in their intestinal system.

One patient, a 38-year-old woman, had chronic inflammation, fluid retention, acne, fatigue, and joint pain, as well as irritable bowel syndrome with bloating and gas. She had tried every known diet, but was unable to lose weight. This woman’s problem: She could not lose weight because she was inflamed. Imbalances in her gut and the food sensitivities that result led to the inflammation. But when we had her eliminate the foods to which she was allergic or sensitive, and gave her some healthy bacteria to heal her gut, she lost 35 pounds in a few months – and all her other symptoms went away too.

The big debate in medicine is which comes first: inflammation or obesity. I have always believed that we become inflamed first, and gain weight second – which makes us even more inflamed, perpetuating the cycle. Now, incredible new research bears this out.

In today’s blog I want to review this research, explain how food allergies can lead to weight gain, and provide you with three steps you can take to eliminate foods you might be allergic to and rebalance the ecosystem in your gut.

Inflammation and Weight Gain

Let me tell you a little more about these studies linking inflammation and weight gain, and explain their implications for treating obesity, heart disease, diabetes, and more.

The first study, published in December 2007, looked at two groups of children. The first group was overweight and the second was normal weight. (i) The researchers measured three key factors connected to inflammation.

First, they looked at high-sensitivity C-reactive protein (CRP), a marker that shows the general level of inflammation in the body. Then they looked for plaque or thickening in the carotid arteries (the main arteries that supply blood to the brain) with an ultrasound. Third, they looked at blood tests for IgG, or delayed food allergies.

What they found was startling.

The overweight kids had a threefold higher level of CRP and a 2.5-fold higher level of IgG antibodies to foods. This is astounding because, in most medical studies, a difference of 20 to 30 percent is considered significant. In this case, the differences were 300 and 250 percent, respectively.

The overweight children also had much thicker carotid arteries, which are a sign of early atherosclerosis and an indicator of heart disease.

The study suggests that these food allergies are a CAUSE of the inflammation and obesity, not a consequence

The authors of the study explain that damage to the gut can lead to a leaky gut, allowing food particles to be exposed to the gut’s immune system. This then triggers a system-wide immune response, leading to inflammation all over the body and producing obesity by increasing insulin resistance.

We already know that inflammation from any cause — bacteria, food, a high-sugar, high-fat diet — will produce insulin resistance, leading to higher insulin levels. And, since insulin is a fat storage hormone, you store more fat — mostly around the belly.

The authors of the study go on to say that we should consider elimination of IgG food allergens as a way of treating obesity and preventing heart disease. That means you don’t limit calories, just allergic foods that cause inflammation.

This study draws a remarkable link that has received little attention by conventional medicine.

So what exactly causes a leaky gut? Well, the next study may help explain just that.

How Your Gut Begins to Leak

The researchers of a study published in the July 2007 issue of Diabetes performed a complex but powerful study to tease out which comes first – the chicken or the egg. (ii)

What they did was quite ingenious. They took thin mice and then fed them a very high-fat diet.

High-fat diets change the bacterial flora in the gut. Toxin-producing bugs are promoted by the high-fat diet while anti-inflammatory and protective bugs die off. (And there are over 500 species of bugs in your gut all fighting for territory.)

In fact, our highly processed, high-sugar, high-fat, low-fiber diet – plus many drugs like antibiotics, steroids, anti-inflammatories, acid-blockers, and hormones – completely alters the bacterial ecosystem in the gut, leading to breakdown, inflammation, and a leaky gut.

The researchers found that mice fed the equivalent of an American diet produced more of a bacterial toxin called LPS, which then leaked into the body through their leaky gut. In humans, these toxins latch onto immune cells, stimulating them to produce a firestorm of inflammatory molecules such as TNFa, IL-6, and IL-1 (cytokines), which in turn block your metabolism and produce insulin resistance, fatty liver, and obesity.

Even more interestingly, the researchers also found that, even with a normal diet, injecting LPS into the mice led to the SAME problems – inflammation and obesity. These mice didn’t eat a bad diet. Just injecting toxins into them made them fat.

In fact, when you eat a bad diet, bad bugs flourish. Your whole gut ecosystem is upset and the outside world “leaks” in across a damaged gut lining. The result is not just obesity, diabetes, and heart disease, but many allergic, autoimmune, and inflammatory diseases as well

The researchers explain how giving antibiotics to rats and cleaning out the bad bugs can prevent diabetes. They explain that by adding soluble fiber to the diet, they can increase the population of the good bugs like Bifidobacteria and decrease the bad bugs – leading to weight loss.

But it doesn’t just happen in lab rats. I have found the same effects when my patients take the special soluble fiber called konjac root or glucomannan. The good bacteria feed on the fiber and reduce inflammation.

And there is more to the gut story. It seems that you are not the only one eating lunch. The bugs in your gut also feast – and they control your fat storage and the calories you absorb. So, people with healthy bugs in the gut lose weight, and those with bad bugs gain weight. (iii)

Now here are a few simple things to try if you are struggling to lose weight or feel better.

3 Steps to Eliminate Food Allergens and Rebalance Your Gut Ecology

  • Try an elimination diet for 3 weeks. Cut out the most common food allergens, including gluten, dairy, eggs, corn, yeast, and peanuts. Some people are sensitive to soy, so you can also cut that out.
  • Eat a whole-foods, plant-based, high-fiber diet. This is essential to feed the good bugs in your gut and to provide the nutrients you need to functional optimally.
  • Take probiotics daily to boost the healthy bacteria in your gut. Look for those that contain 10 billion CFU of bifidobacteria species and lactobacillus species. Choose from reputable brands.

Within a very few short weeks — even if you do nothing else — you will see a dramatic difference that comes from cooling off inflammation by healing your gut.

Remember, if you want to get rid of that gut, you have to fix your gut.


  1. Great article! Inflamation is the cause of many health problems. The bacteria in our intestines plays a major role in our health and weight. Whenever we take antibiotics, all of the bacteria in our digestive system is wiped out…the good and bad. Doctors should be required to tell people when they go on antibiotics to eat yogurt, so that the good bacteria can survive. Either that, or have the prescription label advise you of this. I think that the biggest contributors to bad bacteria flourishing is sugar and bleached flour flour products. High fat consumption is very bad for us too.

    Matt Messner | February 23rd, 2010 | Comment Permalink
  2. How can a person get tested for specific food allergies? Elimination of several groups of foods followed by gradual re-introduction of one at a time would take quite a while.

    Fiona | February 24th, 2010 | Comment Permalink
  3. I am loven this article! I’ve never bought into the fad diets, but since hitting my mid thirties and having 2 babies within 20 months of each other, I’ve really struggled with my weight. I’ve been around 215#’s since my first was born. My joints and back are killing me! I’m all over this- can’t wait to get started!

    Kitt Wilcox | February 24th, 2010 | Comment Permalink
  4. Love this article! Very informative. I’ve had asthma since I was a toddler and I’m now 34. I’m going to try this- hopefully it will help :)

    Joanie | February 24th, 2010 | Comment Permalink
  5. I have always thought there was a correlation between bacteria in our intestines and weight gain. With the over use of antibiotics I believe people are doing more harm than good.

    John Gaddis | February 25th, 2010 | Comment Permalink
  6. I discovered the truth of inflammation several years ago. I was gaining weight without over-eating, I had joint pain, migraines, rosacea, fatigue, and sensitivity to carbs and sugars. When I finally reached my own tipping point, I switched to a whole food, unprocessed, no-added-sugar diet high in protein and with only low-glycemic carbs.

    After my detox period (about 3 weeks), I began feeling better. After three months, I had more energy, it was easier to move, my pain started dropping. I lost weight, and my husband gained weight, eating the same diet.

    After 9 months, I realized that I was sensitive to certain foods. I had decided to allow myself each month to have a “day off”, when I allowed myself foods I had been craving. After three months in a row of waking up the day after my “day off” feeling like I had been poisoned with flu-like symptoms that took a week to resolve, I realized that I needed to control my variables and see what was ‘poisoning’ me. After trial and error, I realized that I’m…sensitive? Allergic? That wheat makes me sick. Not gluten, wheat. And that I can only eat high-glycemic carbs if I am about to, or have just exercised, otherwise they tip my blood-sugar out of whack. Between realizing those two things, and using them to amend the diet I was already on, I had a lot more energy, my rosacea improved, and my constant joint pain was gone!

    If you have a list of discomforts, I suggest you speak with a nutritionist (most doctors aren’t well versed in nutrition) or a naturopathic doctor. And if they feel it’s safe for you, try changing your diet to cut out all the inflammatory foods. If you don’t want to take the time to test-reintroduce foods you want, but aren’t sure how they affect you, you can have food-allergy tests run in combination with the inflammation test.

    It may sound like a lot of work, but being pain free and feeling good in my body is more than worth the foods I’ve had to give up!

    Wishing you health and happiness,

    SpiralCentric | February 25th, 2010 | Comment Permalink
  7. I’ve tried lots of low-fat diets for a couple of years but none of them made me feel satisfied. Although, there are lots of diets,like Atkins diet but it’s making me feel weak and unhealthy. But when I tried Medifast Diet,i feel like I’m on the right kind of diet plan. It doesn’t make me feel weak.

    The caloric intake is around 800-1000 calories.It’s a bit pricey, but there are lots of coupons available on the internet
    Even if you don’t pay full price.You just have to choose a diet plan which your body reacts positively.No one knows your body better than you do…

    Honey P. | April 4th, 2010 | Comment Permalink
  8. My food allergeis aren’t making me fat they’re making me skinny!

    COLLEEN | May 6th, 2010 | Comment Permalink
  9. I have SEVERE food allergies, including all vegetables except onions (go figure). The only meats I can eat are beef and moose (I’m from Alaska, moose is awesome). NO birds. No pork. No bison. Fish is limited but not too bad; NO tilapia, cod, haddock, or polluck. Salmon would be fine except my roommate stops breathing if it’s in the house. I CAN eat all fruits except tomatoes. NO nuts, beans, dairy, eggs, soy, or safflower, canola, or sunflower anything. I CAN eat most grains (wheat, flax, etc.), which is a blessing. HOWEVER… losing weight is near impossible. Fruit and whole grains are very healthy, but when they are one’s staple, it doesn’t do one’s body that much good… especially a body that is hypoglycemic. It’s a constant struggle, and I’m tired in all aspect of the word. I know that I’m not getting my nutritional needs met, and I have gone to multiple doctors, nutritionists, etc., and they all say the same thing: “Avoid the foods that make you sick and here, take all these supplements.” No good, they make me puke.

    Can’t win. Any advice?

    Joanna | December 11th, 2011 | Comment Permalink
  10. Herbalife carries a probiotic. Is that a good product to take? Or can you tell me which one to get. I suffer from a bloated stomach. And gain weight just by looking at food. Also heart palps. Doc says mitral valve. Any advice.

    rosanne | February 29th, 2012 | Comment Permalink

Post a Comment

If you want to show your picture with your comment, go get a gravatar!