Previously obese dieters may struggle to keep weight off because of poor gut bacteria diversity, according to a new study presented today at the European Congress of Endocrinology.
For every cell that makes up the body, there are ten bacteria living on and in it – which means the diversity of bacterial species we have in our system (known as the microbiome) has a huge impact on our health.
Recent studies show that the gut microbiome plays an important role in regulating digestion and energy metabolism, and that obese people have gut bacteria that are better able to extract energy from food. Any surplus energy is converted in the body to fat. As most dieters struggle to keep off the weight they originally lost, manipulating the gut microbiome could be the key to helping stave off obesity and diabetes.
In this study, German researchers from University Hospital Schleswig Holstein in Kiel put eighteen obese adults on a diet of just 800 calories per day for a three month period and tracked how much weight they lost, their sensitivity to insulin, as well as both the activity and diversity of their gut bacteria using stool samples. They then tracked the same factors after putting the dieters on a weight maintenance diet for a further three months. The researchers then compared the results to thirteen obese (control group) and thirteen lean adults who followed their regular diets throughout.
Compared to the control or lean group, they found that the obese dieters had a (beneficially) altered microbiome diversity and metabolism at the end of their three month dieting, but this was not sustained during the three-month weight maintenance phase, despite losing an average of 20kg overall and having improved insulin sensitivity at the end of the six month period.
One of the limitations of the study is that the medications patients may have been taking was not accounted for, which could have an impact on gut bacteria diversity and metabolism.
“Anti-obesity campaigns often recommend low calorie diet programs such as the one we offered here”, said lead author of the study Professor Dr. Matthias Laudes. “However, our work shows that this is not making enough of a long-term change in obese people’s gut bacteria, which may explain why so many of them put weight back on”.
“We want to know why the gut microbiome is resistant to maintaining change after dieting,” he continued. “In the future we will look at the potential of using prebiotics during weight maintenance, or even the potential of faecal transplantation from a healthy gut to that of an obese patient”.