Researchers at the University of Copenhagen have identified new mechanisms of action involving two incretin hormones that could be an effective way of maintaining long-term weight loss.
In a new study, the Copenhagen team explored the interplay of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) – two incretin hormones regulating glucose homeostasis and insulin secretion in people with type 2 diabetes.
The study followed 20 obese individuals throughout an eight-week low-calorie powder diet plan, resulting in an estimated 13 per cent decrease of their body weight on average.
The initial weight loss programme was then superseded by a 52-week maintenance protocol of mild calorie restriction.
During that time, Associate Professor Signe Sorensen Torekov from the Department of Biomedical Sciences and his colleagues have collected three blood samples – before weight loss, immediately after weight loss and at the end of the 52 weeks – to monitor postprandial and fasting levels of the two appetite inhibiting hormones GLP-1 and PYY.
After one year of stable weight loss, the study revealed an inversely proportional change in the levels of GLP-1 – that are often very low in obese people – and those of the hunger hormone ghrelin.
The first author of the study and PhD student, Eva Winning Iepse, reported that GLP-1 increased from before-weight loss level in contrast to ghreli, which increased immediately after weight loss but returned to normal levels (a sign of lower hunger) after one year.
Variations in these two hormones demonstrates that the body is able to adapt to a lower energy consumption after the one-year mark, and reach a new more optimal state of homeostasis, helping people keeping the weight off.
The research, published in the European Journal of Endocrinology, also suggests that the thermodynamics hypothesis of energy balance (calories-in-calories-out), purported as the solution for weight loss, is slowly shifting to a concept of complex hormone interactions facilitating the continuation of lower body weight.