A New Theory of Obesity - Scientific American

Obesity is a global epidemic and is far more prevalent in countries that adopt Western patterns of eating. Western patterns of eating include highly processed foods with lots of sugar and fat and the removal of fiber. The U.S. Department of Agriculture (USDA) defines processed food as one that has undergone any change to its natural state. If you’re interested in the amount of processing your food has experienced, refer to the NOVA Food Classification Scale.

Many pundits blame the obesity crisis on the prevalence of sugar and fat. But the truth is likely far more complex. I recently read a Scientific American article from October 2019 entitled A New Theory of Obesity. The authors theorize the obesity crisis is not due to sugar or fat alone, but rather the amount of processed food we consume. Processing, among other things, makes the components of the food more readily accessible to our bodies. Our bodies evolved to consume plants and other foods in their natural form. Processing throws this ancient system out of whack. The SciAm article theorizes that processed foods distort the delicate signaling between the gut and the brain, causing those eating processed foods to consume significantly more calories.

Although the article does not go into detail, the consumption of large amounts of processed food is associated with a wide range of chronic diseases. In two papers published last year in the BMJ, the more ultra-processed food a person ate, the more likely they were to die from cardiovascular problems and to die from any cause.

With the growing body of literature on the detrimental impact of processed food on health, easy access to NOVA scores would be significant. Unfortunately, they are not easily accessed. The food industry has fought the inclusion of NOVA Classification addition on food labels, so the public is blissfully unaware of the threat to their health and well-being.

Although I find the theory in the SciAm article compelling, I believe their theory is incomplete. The report largely ignores the influence of the microbiome on health, chronic disease, and obesity. Some of the original microbiome studies focused on the ability of certain gut bacteria to more efficiently extract calories from food and the ability to “transplant” obesity into lean mice given a fecal microbiota transplant (FMT). Some early microbiome research demonstrated association of western patterns of eating and obesity,. In mice, the gut flora pattern changed in as little as 24 hours after the initiation of a western diet.

Similarly, rapid, predictable shifts in microbial presence are seen in humans rapidly after eating a western diet. A diet rich in ultra-processed foods rapidly decreases the diversity of species in your gut and leads to a state called dysbiosis. Diversity in the population of bacteria in your gut is a good thing. Ultra-processed foods impact the variety of your gut flora profoundly.

This shift in flora fascinates me as it is associated with a wide range of chronic diseases, including obesity, cardiovascular disease, autoimmune disease, and even cancer. The commonality between all these diseases is inflammation. Consumption of processed foods increases systemic inflammation, likely through alteration of gut flora. Systemic inflammation rapidly rises with a diet rich in processed foods. The effects on the body likely come from the ultra processing, the high sugar and fat content, and the lack of fiber. Fiber is especially important as a prebiotic, nourishing bacterial species that give off anti-inflammatory chemicals such as short-chain fatty acids.

Another likely culprit of ultra-processed foods are emulsifiers. Emulsifiers are additives used to stabilize processed food. Emulsifiers have a broad range of impacts on health. Emulsifiers can decrease the mucous layer of the gut (required for healthy gut function and a well-tuned immune system) and shift the native species present in the gut. In mice, certain emulsifiers can cause inflammation of the colon and other detrimental effects. I’ve become increasingly suspicious of how these emulsifiers contribute to poor health. When I look at food labels, I invariable scan for emulsifiers and other additives.

The upshot of the SciAM article is to eat a whole plant-based foods diet. By eating complete foods, the body’s complex digestive system works as it is meant to.

Many people who want to make healthy changes in their life are flummoxed where to start. My initial response is almost always “stop eating processed food.” Making this simple change can have a profound effect on your health and well-being.