Muscles Turning Into Fat?

Category: Fitness

It's a common myth that muscles will turn to fat when taking an extended break from exercising. However, a long exercise break (called deconditioning) will not cause muscles to turn to fat. Instead, after more than six weeks of inactivity muscles will decrease in size and there will be significant declines in cardiovascular fitness, strength, endurance, and flexibility. Although muscles don't turn to fat, the muscles of obese people have an increased tendency to store fat. Now research reports that obese people have significantly increased levels of a fat-building enzyme called SCD1 in their muscle cells that cause muscles to store fat.

The study, published in Cell Metabolism, examined the muscle cells of lean and obese women. Researchers from Louisiana State University in Baton Rouge analyzed data from obese and lean women, matched for the same age and race. The lean women had a BMI (body mass index) of 25 or less and the obese women had a BMI of 35 or more. The researchers obtained SCD1 levels from the participants' muscles.

The researchers found that the obese participants had three times more SCD1 in their muscles than the lean participants. This result implies that SCD1 production is genetically programmed. The study authors suggest that obesity turns on the SCD1 gene, programming muscles to store excess fat.

"These results suggest that elevated expression of SCD1 in skeletal muscle contributes to abnormal lipid metabolism and progression of obesity," the study authors write.


REFERENCES:
1. Hulver MW et al. Elevated stearoyl-CoA desaturase-1 expression in skeletal muscle contributes to abnormal fatty acid partitioning in obese humans. Cell Metab 2005 Nov;2(5):275-6

Posted by Elaine Gavalas on May 15, 2013 11:00 AM