Researchers Try to Understand the Link Between Obesity and Lockdown

Researchers of the Ben-Gurion University of the Negev, National Institute for Biotechnology in the Negev, and Soroka University Medical Center simulated decline in physical activity by removing a voluntary running wheel and assessed how diet composition affects the response in mice. They found that while less energy was spent by the mice, the mice still ate similar amounts of food as when the running wheel was present, which resulted in weight gain.

And, diet composition determined changes in the oxidation rates of fat or carbohydrates – the two major energy sources of our body – in response to the decline in physical activity.

Their findings were published in the Physiological Reports, a journal of the American Physiological Society.

The mice were divided into two groups: one was fed a low-fat diet and the other a high-fat diet for six days. Mice were placed in metabolic cages, which measure their activity, food consumption, the amount of oxygen they consume and carbon dioxide (CO2) they release cycle. After three days, the running wheel was removed.

Diet determined how much fat or carbohydrates were burned. With the running wheel in the cage, high-fat diet mice burned mainly fat throughout the day, and carbohydrate burning decreased, even more, when their physical activity dropped.

The reverse was true for the low-fat mice, who consumed during their wake hours more carbohydrates and decreased burning fat even further when the running wheel was taken out of the cage.

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“Our findings show that there are immediate effects of exercise stoppage. While the comparison to human beings forced to become more sedentary during lockdowns requires confirmation in human clinical trials, our study provides a possible explanation as to how lockdowns may have induced weight gain. While the decline in spending energy is rapid, matching the lower energetic needs with lower food consumption takes time, resulting in a positive energy balance”, says Prof. Rudich.

Dr. Uri Yoel adds: “Dietary composition determined the adaptation to less physical activity – the “rarer” energy source in the diet was the one that the mice chose to burn less of once the energy demand decreased.

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If also true in humans – this may have consequences on metabolism that need to be taken into consideration, particularly in persons with impaired metabolic regulation, such as diabetes.”

The study was supported by a U.S.-Israel Binational Science Foundation Grant (No. 2017027), to Prof. Assaf Rudich and G. William Wong, one of the co-authors, professor of Physiology at Johns Hopkins School of Medicine.



Source-Medindia