According to a recent study, a group of researchers have found that gut bacteria could affect your ability to lose or gain weight. Researchers enrolled 62 participants who all had large waist circumferences. They were instructed to follow either the New Nordic Diet (dark greens, berries, wholegrains) or the Average Danish Diet (lean meat, eggs, lettuce, coffee, no grains) and were grouped based on how much of two different types of bacteria – Prevotella and Bacteroides – they had in their gut.

The two diets vary greatly in the amount of fibre you consume, with the New Nordic Diet being much more fibre-rich. Participants followed the diets for 26 weeks, with their body measurements taken before and after. After this initial period, all participants followed the New Nordic Diet for another year. he researchers found that those who had a higher ratio of Prevotella to Bacteroides and followed the New Nordic Diet lost more body fat than those with the same ratio following the Average Danish Diet. When the ratio was reversed, there was no difference in weight loss between the two diets. Study’s co-author Mads Hjorth explained, “People with a high Prevotella/Bacteroides ratio were more susceptible to body fat loss on a diet rich in fibre and wholegrain compared to an average Danish diet.”

Adding, “The health promoting aspects of the New Nordic Diet in terms of body weight regulation seem mainly to apply to a subset of the population. This could apply to as much as half of the population.” The research reinforces the idea that nutrition should be personal, and what works for one person won’t necessarily work for another. “These results are a breakthrough demonstrating that certain bacterial species play a decisive role in weight regulation and weight loss,” noted lead researcher Arne Astrup. The lead researcher concluded by saying, “Now we can explain why a high fibre diet does not always lead to weight loss. Human intestinal bacteria is an important part of the answer and will from now on play a role in the treatment of the overweight.”