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Microbiome and Weight Gain

Some guts are better than others at harvesting energy.

Microbiome and Weight Gain

Unfair as it is, have you ever noticed how some people gain weight by even looking at a donut while others can inhale them without ever seemingly packing on any extra poundage? Perhaps the microbiome is at play here for weight gain.

Scientists from the University of Copenhagen took a step toward understanding why some people gain more weight than others, even when they eat nearly the same. The team discovered that the composition of gut microbes that generally extracts more energy from food is different in in one segment of the population.

The research, published in Microbiome, analyzed the residual energy in the feces of 85 Danes to estimate how effective their gut microbes were at extracting calories from the food they ate. At the same time, the composition of gut microbes for each participant was mapped. Roughly 40% of the participants were found to belong to a group that gleans more energy from food (compared with the other 60%).

It appears the so-called B-type composition (dominated by Bacteroides bacteria in the gut) may result in more calories being available for the human host from the same amount of food. It was also observed that those who extracted the most energy from food (as indicated by less energy left in their stool samples) also weighed 10% more on average.

Results indicate that being overweight or obese might not just be related to eating and exercise habits, but may also have something to do with the composition of a person’s gut microbes—but the microbiome and weight gain all need further investigation. For instance, could there be ways that the microbiome can be manipulated to make it less efficient at extracting as many calories from its host’s dinner?

See also: Gut Microbiome and Athletic Performance


Matthew Kadey, MS, RD

Matthew Kadey, MS, RD, is a James Beard Award–winning food journalist, dietitian and author of the cookbook Rocket Fuel: Power-Packed Food for Sport + Adventure (VeloPress 2016). He has written for dozens of magazines, including Runner’s World, Men’s Health, Shape, Men’s Fitness and Muscle and Fitness.

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