High-fiber diets are said to cause a little bloating by stimulating some fiber-digesting gut bacteria species, which produce gas as a by-product. Fiber is an important nutrient that should be consumed regularly, but its excessive consumption may not be good for you if you are watching your waistline. And, if your high-fiber diet is coupled with a protein-rich diet, it may further lead to even more bloating. However, if the high-fibre diet is paired with a carb-rich diet, it may not escalate the problem that much. The study was conducted by researchers at the Johns Hopkins Bloomberg School of Public Health.

For the study, the researchers examined a dietary clinical trial that was conducted in the years between 2003 and 2005 in Boston. It involved 164 participants who had high blood pressure. They were fed three different diets over a time period of consecutive six weeks with a two-week break in between when the participants had their regular diet. 

The participants, who ate versions of a heart-healthy, high-fiber diet that was relatively rich in plant protein, were about 40 percent more likely to develop bloating symptoms as compared to a carbohydrate-rich version of the same high fiber diet.

Study co-senior author Noel Mueller, Ph.D., an assistant professor in the Department of Epidemiology at the Bloomberg School said, “It’s possible that in this study, the protein-rich version of the diet caused more bloating because it caused more of a healthy shift in the composition of the microbiome. Notably, the protein in these diets was mostly from vegetable sources such as beans, legumes, and nuts.”

The study further suggests that if high-quality carb calories like whole-grain are substituted with protein calories, the chances of bloating may be reduced for those on high fiber diets, making such diets more tolerable.

Referance: https://food.ndtv.com/news/high-protein-content-in-fibre-rich-diet-may-cause-bloating-finds-a-study-2171457