This study published in Nature Communications reveals that when it comes to weight loss, not all calories are created equal.

Researchers from Arizona State University and AdventHealth Translational Research Institute conducted a study to examine how different diets impact calorie absorption and weight loss, highlighting the significant role of the gut microbiome.

In this study, participants followed two distinct diets for 22 days each: a high-fiber, whole foods diet and a typical Western diet consisting of processed foods. Both diets provided the same number of calories and similar proportions of protein, fat, and carbohydrates. The results showed that participants on the high-fiber diet absorbed significantly fewer calories compared to those on the processed food diet. Specifically, an additional 116 calories per day were lost in feces on the high-fiber diet. This difference is attributed to the high-fiber diet nourishing the gut microbiome, which leads to more energy being used by gut bacteria rather than being absorbed by the body.

Furthermore, participants on the high-fiber diet lost slightly more weight and body fat than those on the processed food diet. They also had increased levels of short-chain fatty acids (SCFAs) and the hormone GLP-1, which promotes feelings of fullness. These findings underscore the importance of dietary composition over mere calorie counting for effective weight management and metabolic health.

The study demonstrates that the gut microbiome plays a crucial role in energy balance and suggests that diets rich in fiber and whole foods can enhance microbial health and contribute to weight loss more effectively than diets high in processed foods, even when calorie intake is the same.

References

Richards, M. J., Becattini, S., Dickson, J. L., et al. (2023). Microbiota-accessible carbohydrates suppress host adiposity by regulating gut microbial ecology and metabolism. Nature Communications, 14, 40229.