Does Wheat Cause Weight Gain?

An update to the 2012 post by Stacy St Germain

As a nutritionist, I do my best to understand research around diet trends and to keep up with whatever is in vogue.  The gluten-free diet has been studied and debated among health professionals heavily over the past decade and warrants a modern and objective look at wheat and weight gain. This blog post has been updated from its original publication in 2012.

Wheat, gluten, and the effects on the body, are topics with lots of depth and angles. Learn more about the labs we offer for wheat and other foods.  Contact our office if you’d like to learn about whether wheat in your diet might be impacting your health goals.

The famous book, Wheat Belly was written by cardiologist Dr. William Davis. It was published in 2011 and has over 1 million copies sold.  Dr. Mark Hyman also published an article in 2012, “Three Hidden Ways Wheat Makes You Fat”.

The National Institutes of Health published a meta-analysis in 2019 which reported higher intake of wheat lead to lower BMI in observational studies, but that random control trials were inconclusive and the researchers recommended additional research to clarify the potential role of wheat gluten in body weight.  (It should be noted that the study was funded by General Mills.).

What then do we now understand about wheat and weight gain? There’s no scientific evidence that wheat or gluten directly cause weight gain. However, underlying conditions can contribute to weight gain, and both wheat and its protein, gluten, may influence those mechanisms.


Inflammation in the Digestive System

To understand the effects of wheat on the body, we start at the beginning — in the digestive system — and examine its proteins. The most familiar of these is gluten.

Gluten is the sticky protein in wheat that holds bread together and makes it rise.  It has been studied thoroughly for its role in Celiac disease, an autoimmune disorder against the digestive system triggered by gluten proteins. People with Non-Celiac-Gluten-Sensitivity (NSGS) experience symptoms triggered by gluten without the immune reaction- such as bloating, irregular bowel movements, fatigue, brain fog or joint pain.  For people in both cases, gluten contributes to inflammation of the intestinal cells.

Poor Nutrient Break-Down

The inflammation impairs digestion, so food doesn’t get broken into usable nutrients and can be left sitting in the intestines.  Undigested food causes uncomfortable bloat and more inflammation.  Nutrients from your diet that should fuel the metabolism that helps you use the calories you eat for energy can’t get into the system.  Deficiencies slow you down, make you tired, and contribute to weight gain.

Leaky Gut

Inflammation in the digestive system can lead to gaps in the intestinal barrier, also known as intestinal impermeability, or Leaky Gut Syndrome.  In this case, large, undigested, molecules pass through the digestive lining into the blood stream and contribute to systemic (all over) inflammation. This kind of inflammation puts the body into an “unwell” state where metabolism slows down, the immune system is activated and there is an increase in metabolic wastes. All of which contribute to weight gain.

Microbiome

Lastly, inflammation in the digestive system affects the ecosystem of the digestive microbiome. Beneficial microbes help support the immune system, the health of the cells in the digestive system, and even help to regulate blood sugar, and promote energy metabolism. Imbalance in these microbes contribute to weight gain.

Digestive inflammation isn’t always caused by wheat, but if you’re curious about these factors or whether wheat may be a problem for you we encourage you to connect with one of our health practitioners to learn more.


Effects on Blood Sugar Balance

It would be unrealistic to assume that most wheat consumed in the U.S. is in the form of whole grains, such as farro or wheat berries.  Rather, wheat is more common in our diet as breads, pasta or other processed flours.  The processed flours, even those from whole wheat, have a higher glycemic index and raise blood sugar.

The increase in blood sugar triggers a rise in insulin to manage the energy source (glucose).  If you aren’t burning a bunch of calories after your meal, then insulin takes that glucose to storage – mostly into adipose (fat) cells.

It should be recognized that even processed grains from gluten-free flours will raise glucose and could be contributing to stubborn belly fat.  If you’re curious about whether this is a contributing factor for you, eliminate wheat and gluten foods for 30 days and replace them with whole vegetables or whole grains, instead of “gluten-free” packaged products. For example, spiralized zucchini for your pasta or a quinoa bowl for your sandwich.

There are many contributors to high blood sugar and keeping blood sugar regulated is one of the health goals that you’re struggling to manage our practitioners can help.

While there’s no definitive proof that wheat directly causes weight gain, its role in fueling digestive inflammation and blood sugar dysregulation can contribute to unwanted belly fat. By focusing on whole food sources of vegetables and gluten-free whole grains, you can ease gut irritation, stabilize blood sugar, and make it easier for your body to maintain a healthy weight.