Obesity is linked to a number of comorbidities, including musculoskeletal disorders. Focusing on the important role muscles play in metabolism, a recent study examined how time-restricted feeding in overweight fruit flies impacted the factors underlying obesity’s effects on muscle function.
Skeletal muscles are crucial to metabolism. After eating, the muscles take up 70% to 90% of glucose from the blood to fuel muscle contraction. The process is activated by two pathways: one stimulated by insulin and the second by muscular contractions.
Muscle dysfunction caused by obesity can interfere with this metabolic process, leading to insulin resistance and low energy levels. Studies have shown that time-restricted feeding (TRF) – eating for a certain number of hours a day – can protect against obesity and the muscular dysfunction caused by the disease. Although the method underlying these benefits is not well known.
In a new study, researchers looked at how TRF, a natural, non-pharmacological intervention aimed at reducing weight, affected obese fruit flies (Drosophila melanogaster). Fruit flies are perfect for use in genetic studies as they share 75% of the genes that cause disease in humans.
The study, led by researchers at the University of Alabama at Birmingham, examined the genetic mechanisms underpinning how TRF improved skeletal muscle performance.
The fruit flies were subjected to either a regular or high-fat diet. The flies given the high-fat diet were allowed to feed 24 hours a day, whereas the TRF flies only had access to a high-fat diet for 12 hours a day. The flies’ flight muscles were examined through flight tests, and their muscle tissue, gene expression, and metabolism were analyzed.
The researchers found that obese fruit flies who had undergone TRF showed improved muscle performance, reduced intramuscular fat, and lowered levels of the marker for insulin resistance.
There was an increase (upregulation) in genes related to the production and use of glycine, a non-essential amino acid important to human metabolism, and a reduction in an enzyme involved in the process of creating triglycerides, a type of fat found in the blood.
When we eat, our body converts unused calories into triglycerides. High triglycerides are associated with hardening of the arteries (arteriosclerosis), which increases the risk of heart attack, heart disease, and stroke.
“The prevalence of obesity continues to be a worldwide growing issue associated with crippling health care and economic burdens,” said Girish Melkani, PhD, corresponding author of the study. “Obesity is associated with various comorbidities, especially high-caloric diets and genetic predisposition. This study elucidates potential mechanisms behind time-restricted feeding’s protective properties against skeletal muscle dysfunction and metabolic impairment induced by obesity."
The findings may lead to further studies into TRF to better understand its benefits in restoring muscle function, paving the way for a natural and affordable alternative treatment for muscle and metabolic dysfunction caused by obesity.
The study was published in Nature Communications.
