study: can a high fibre diet support weight loss?

Written by Monica Mischie

Look, us mere mortals never really get to find out what is going on in the world of science, well, not unless it’s (sometimes) sensationalised in the press. So, we wanted to bring you a snapshot of the latest science. To whet your appetite to find out more if it’s something that piques your interest, or simply to keep you all in the “gut world” loop. Remember most of the studies are VERY new science, so keep your critical thinking cap on!

Our report into high fibre diet and weight loss is brought to you by our student research squad. They have their ears to the lab floor ground to keep us all informed.

 

Background

A study published in The Journal of Nutrition followed 70 overweight people (32 men and 38 women) over a 6-week high fibre diet (33g or 23g per day) intervention.

 

Key findings

Knowing about the type of bacteria living in your gut may give some guidance for personalised diets. This supports overweight people who want to lose weight.

Consumption of whole grain foods (whole wheat, oatmeal or brown rice) and of refined wheat (wheat with few fibres, iron and B vitamins) foods has different effects. Effects on the weight of overweight people depending on the composition of their gut bacteria.

 

Type of study

Randomised, dietary intervention study on healthy, overweight people. Each participant was randomly assigned to have a diet enriched in one of the following three foods: whole grain wheat, whole grain rye or refined wheat over 6 weeks. Whole grains diets had 33g of fibres/day, whereas refined wheat diet had 23g of fibres/day.

 

Study Findings

Participants who had more of a gut bacteria type (Prevotella) at the start of the study and were on the whole grain diets lost more weight (1.8kg) than participants who also had more of Prevotella but were on the refined wheat diet.
The gut bacteria Prevotella is more common in people on fibre-rich diets. It was shown before to be associated with better general health.

 

Study Limitations

Whilst the results are really interesting, it was only over 6 weeks with just 70 people in Denmark. So, we need larger more robust studies spanning different populations and over a longer period of time to draw some more concrete conclusions around gut bacteria and weight loss.

 

Conclusion

This study shows that our gut microbiome composition shapes our bodies’ responses to various foods. It may explain why certain weight-loss diets aren’t always effective.

Since our gut has trillions of bacteria, we need more research to find out how other gut bacteria respond to the same/other dietary interventions, And how these, in turn, affect our bodies.

 

About the author

Monica Mischie obtained an Msci in Human Genetics from University College London in 2018. She is now doing a Ph.D. on the gut microbiome and dietary fibres at Imperial College London. She loves cooking, discovering new flavour combinations, and visiting farmers’ markets.