US, July 22 -- Repeatedly losing and gaining weight may do more than frustrate dieters - it also accelerates muscle loss in middle-aged people, according to new UC San Francisco research that comes as weight-loss medications transform obesity treatment.

In a study published in Radiology, the researchers found that people whose weight repeatedly fluctuated lost significantly more thigh muscle over four years than people whose weight remained relatively steady, even though both groups finished the study at about the same overall weight as when they began.

"When people's weight cycled, they lost tremendous amounts of muscle along with the fat, and they didn't gain the muscle back," said Thomas Link, MD, PhD, professor of Radiology, who le...