A new study from researchers at the Mayo Clinic may shed some light on why certain people can lose more weight than others despite adhering to the same regime of exercise and caloric restriction. Alongside a myriad of other recent medical discoveries, the secret may lie in the unique make-up of our gut bacteria.

A huge assortment of factors underly the pathophysiology of obesity. From genetics to environmental factors there will always be a huge number of reasons determining how an individual specifically metabolizes energy. An interesting growing body of research is now revealing that the make up of our gut microbiome could be playing a major part in explaining why some people can lose weight more easily than others.

The new study set out to examine variations in gut bacteria in obese subjects trying to lose weight. The results revealed that there were indeed differences in gut bacteria between those successful in losing weight and those who weren't.

"Gut bacteria have the capacity to break down complex food particles, which provides us with additional energy. And this is normally is good for us," explains Vandana Nehra, co-senior author on the study. "However, for some individuals trying to lose weight, this process may become a hindrance."

Two specific genus of bacteria immediately stood out in the results. Phascolarctobacterium, a reasonably common type of bacteria was seen in increased levels in subjects successful in losing weight, while an increased abundance of Dialister was identified in those less able to lose weight. The actual mechanisms these bacteria use to influence energy expenditure and metabolism is unknown at this stage, but they could be initially used as biomarkers to help clinicians better tailor individualized weight loss programs.

Another fascinating outcome from the research related to enzymes involved in carbohydrate metabolism. Examining differences between those successful and those unsuccessful in losing weight, the study measured the volume of genes that are known to encode gut microbial carbohydrate-active enzymes. It was found that those less able to lose weight displayed an increased capacity for carbohydrate metabolism. This essentially means some people can more effectively metabolize carbohydrates, and subsequently have more difficulty in losing weight though caloric restriction and increased physical activity.

The research is still in its preliminary stages, and further work needs to be done before a greater understanding into what specific gut bacteria could be releasing these carbohydrate-active enzymes, and whether interventions could be made to disrupt this mechanism. However, the study offers a fascinating insight into how gut bacteria could potentially be modulating our ability to metabolize certain carbohydrates, and it puts another nail in the coffin of the old, oversimplified "calories in calories out" equation for weight loss.

"While we need to replicate these findings in a bigger study, we now have an important direction to pursue in terms of potentially providing more individualized strategies for people who struggle with obesity," says Purna Kashyap, co-senior author on the study.

The study was recently published in Mayo Clinic Proceedings.

Source: Mayo Clinic