Clock disturbance preceded weight gain in rats on a high fat diet.
A high fat diet seems to cause weight gain by blunting a body clock that controls feelings of fullness, according to a paper in Journal of Physiology. The new research, done in rats could lead to new ways of treating obesity that focus on the body clock.
Obesity is increasing worldwide with more than 1.9 billion adults either overweight or obese in 2016, according to the World Health Organization. The condition is a risk factor for many diseases including heart disease, diabetes and some cancers and it is difficult to treat by dieting.
There are “clocks” in many parts of the brain, controlling the daily rhythm of different body processes, according to recent research. Previous work by the study authors showed that the dorsal vagal complex, thought to control food intake, is one such clock. They set out to discover whether this clock was affected by diet and how.
The researchers led by Lukasz Chrobok at Jagiellonian University in Poland took two groups of rats and fed the first with a high fat diet containing 70% of energy from fat and the second control group a diet that contained only 10% of energy from fat. They monitored the rats’ food intake patterns, their weight and DVC activity for 4 weeks of these diets.
They found that the high fat diet increased food intake in the rats during the day (their sleep phase) and blunted the daily rhythm in DVC activity. The diet dampened the DVC’s responses to neuropeptides associated with metabolism. All the changes occurred without much weight gain, suggesting changes to the body clocks occur before weight is gained.
Lukasz Chrobok, said: “I’m really excited about this research because of the possibilities it opens up to tackle the growing health issue of obesity.”
Humans and rats share many brain features in common but one limitation of the study is that rats are nocturnal while humans are not and this would impact how the DVC works.
Find out more
Search for: “fat and "food intake" and ("body clock" or circadian)
Reference:
Chrobok, L., Klich, J.D., Sanetra, A.M., Jeczmien-Lazur, J.S., Pradel, K., Palus-Chramiec, K., Kepczynski, M., Piggins, H.D. and Lewandowski, M.H. (2021), Rhythmic neuronal activities of the rat nucleus of the solitary tract are impaired by high-fat diet - implications for daily control of satiety. J Physiol. Accepted Author Manuscript. https://doi.org/10.1113/JP281838