THE ESSENTIAL
- New drugs like semaglutide (Wegovy) and tirzepatide (Mounjaro) allow weight losses of up to 20% of body weight.
- But up to a third of that lost weight is a loss of lean body mass, including muscle and bone, which are essential for overall health. This can weaken bones and compromise blood sugar control, increasing the risk of diabetes.
- To limit these effects, it is crucial to combine these treatments with a diet rich in proteins and regular physical activity.
GLP-1 drugs, which regulate appetite, represent a promising advance in the treatment of obesity. These treatments, such as semaglutide (Wegovy) and tirzepatide (Mounjaro), help patients feel less hungry and thus reduce their food intake. Clinical research shows that they provide weight loss of up to 20% of body weight in some obese people.
However, not all the weight lost is made up of fat, recalls researcher Jennifer James, of the University of Liverpool, in an article published in The Conversation. Up to a third corresponds to a loss of lean mass, including muscles and bones. A phenomenon similar to that observed after strict diets or bariatric surgeries.
A loss of lean mass is harmful to health
Problem is, muscle and bone mass play a crucial role in our health. Muscles, for example, are essential for regulating blood sugar levels. A reduction in muscle mass can therefore affect blood sugar control, thus increasing the risk of type 2 diabetes, but also blindness, nerve damage and even vascular problems. As for bones, their weakening increases the risk of fractures, compromising our ability to perform daily activities.
The exact mechanisms of this loss remain unclear. Scientists assume that during weight loss, muscle proteins break down faster than they are replenished. And, because there is less pressure on the bones due to the weight lost, the bones would have more difficulty renewing themselves normally, leading to less bone mass being made than before the weight loss.
How to preserve your muscles and bones?
To minimize their side effects, it is essential to combine these medications with healthy habits that promote the maintenance of lean mass. A diet rich in protein and regular physical activity are particularly essential. Resistance exercises, such as weight training, are particularly effective for maintaining muscle mass. If your schedule is busy, small actions “like taking the stairs or walking faster” can also make a difference, concludes Jennifer James.
