Gut microbiota plasticity is correlated with sustained weight loss on a low-carb or low-fat dietary intervention.

Scientific reports. 2020;10(1):1405

Plain language summary

Obesity is responsible for a substantial number of deaths and is associated with considerable economic costs. Dietary intervention can help with weight loss; however, success varies between individuals. Gut microbiota could influence weight loss as they have been shown in previous studies to affect feelings of hunger. This cohort study taken from an RCT of 161 obese adults aimed to determine if differing gut microbiota communities could be involved in determining weight loss success when on a low-carbohydrate or a low-fat diet over 12 months. The results showed that specific gut microbiota did not predict weight loss success. However, having a diverse gut microbiota prior to starting a low-fat diet, predicted higher weight loss. This was only observed in those on a low-carbohydrate diet after 10 weeks of dieting. Interestingly individuals that reported better dietary adherence weren’t necessarily more successful with weight loss. It was concluded that gut microbiota diversity is important in sustained weight loss, especially if on a low-fat diet. This study could be used by healthcare professionals to understand that microbial diversity may determine the success of a diet regime and the importance of personalising recommendations.


While low-carbohydrate and low-fat diets can both lead to weight-loss, a substantial variability in achieved long-term outcomes exists among obese but otherwise healthy adults. We examined the hypothesis that structural differences in the gut microbiota explain a portion of variability in weight-loss using two cohorts of obese adults enrolled in the Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) study. A total of 161 pre-diet fecal samples were sequenced from a discovery cohort (n = 66) and 106 from a validation cohort (n = 56). An additional 157 fecal samples were sequenced from the discovery cohort after 10 weeks of dietary intervention. We found no specific bacterial signatures associated with weight loss that were consistent across both cohorts. However, the gut microbiota plasticity (i.e. variability), was correlated with long-term (12-month) weight loss in a diet-dependent manner; on the low-fat diet subjects with higher pre-diet daily plasticity had higher sustained weight loss, whereas on the low-carbohydrate diet those with higher plasticity over 10 weeks of dieting had higher 12-month weight loss. Our findings suggest the potential importance of gut microbiota plasticity for sustained weight-loss. We highlight the advantages of evaluating kinetic trends and assessing reproducibility in studies of the gut microbiota.

Lifestyle medicine

Fundamental Clinical Imbalances : Digestive, absorptive and microbiological
Patient Centred Factors : Mediators/Obesity
Environmental Inputs : Diet ; Microorganisms
Personal Lifestyle Factors : Nutrition
Functional Laboratory Testing : Stool

Methodological quality