It’s normal to lose lean mass, including muscle, during any type of weight loss intervention, but too much muscle loss can be a problem. Weight loss drugs have soared in popularity in the past year, helping some lose dramatic amounts of weight — but not all that weight is fat. Some of that is actually lean mass, which is everything in the body that isn’t fat, including your bones, organs and, importantly, muscle.
“When we look at weight reduction from any intervention, about one-third of the weight we lose tends to be lean mass, and that can be problematic,” said Dr. Jaime Almandoz, an associate professor of internal medicine in the Division of Endocrinology at UT Southwestern Medical Center in Dallas. That lean mass loss is generally from muscle. “Lean mass is healthier and associated with better metabolism, so when we lose lean mass, we may lose some of that function.”
The more muscle mass a person has, the better the resting metabolic rate, or the number of calories a person burns at rest. When a person loses muscle mass, the resting metabolic rate decreases, too.
Excerpted from NBC News