Weight Management

How gut bacteria can affect body weight

by Dr. Malisa M. Carullo MSc, ND

Are you struggling to maintain a healthy weight? If so, you may want to check in with your gut. Research has shown that our gut bacteria — specifically, the wrong kind of gut bacteria, or lack of microbial diversity — can hinder weight management.

Gut health: an overview

Our intestines, or gut, are key to our digestive system and have been linked to many other aspects of our health, affecting everything from our cognitive well-being to our skin health and potentially our ability to lose weight.

Our gut hosts 100 trillion microbes at any given time, and the majority of these microflora are good for us. That said, not all microbes provide the same health benefits.

This is because we each have a unique composition of microbiota in our gut microbiome — consisting of various strains of bacteria, viruses, and protozoa (a group of single-celled microorganisms) — some of which have been shown to influence our weight and overall health. If our microbiota become less diverse, or if the amount of specific, beneficial microbes in the gut shifts, it may affect our health in various ways.

What factors influence the gut microbiome?

Our gut breaks down the food we eat into small particles. The smallest particles are absorbed into the blood, while the rest are eliminated from the body.

The process of digestion that takes place in the intestines is where the impact of gut bacteria is the most significant.

While the majority of these bacteria help to break down food and nutrients in the gut, some are better-equipped to facilitate digestion, and potentially help with weight management, than others.

Put simply: If the gut has higher levels of certain types of bacteria, this could be a reason why it’s more difficult to lose weight. Some factors that can disrupt the gut microbiome and affect weight management include:

Poor diet — Fibre fuels healthy bacteria, while sugar promotes unwanted types of bacterial strains, parasites, and yeast. Research has shown a fibrous, low-sugar diet is better for gut health.

Sedentary lifestyle — If you don’t get much exercise, you may want to rethink your approach. Lack of physical activity may reduce gut bacterial diversity and potentially make you more susceptible to weight gain.

Stress — Even the most relaxed people experience stress from time to time. Chronic stress is much more serious, however, as it can disrupt the gut microbiome, reducing the numbers of beneficial bacteria for weight management as well as affecting overall health.

Strategies to improve gut health and promote weight loss

Results from a study published in the Mayo Clinic Proceedings reveals that even with a strict diet and exercise program, specific activities of the gut bacteria can disrupt the microbiome and make weight loss difficult.

This is important because currently, more than two-thirds of North American adults are either overweight or at risk of being overweight. Healthy weight loss and management are crucial to overall health — and this is where understanding research on probiotic strains is valuable.

In addition to a nutritious diet and regular exercise, certain strains may improve gut function. Clinical studies have shown that strains, such as Bifidobacterium lactis B420, support body weight regulation and have been shown to help control body weight and body fat.

While certain probiotic strains may be ideal for weight management, along with a comprehensive wellness regimen, they are not a substitute for a healthful diet and active lifestyle. Please speak to your healthcare practitioner before changing your diet.

Dr. Malisa M. Carullo MSc, ND, is a naturopathic physician and currently manages medical information, oversees safety, pharmacovigilance, and product training for Metagenics North America.