Dr. Isabel Viñas, expert in metabolism and hormones: "If you lose 20 kilos, the question is not how much you have lost, but what you have lost"

The article discusses the implications of weight loss on muscle mass, particularly in the context of GLP-1 receptor agonists like Ozempic. Dr. Isabel Viña emphasizes that losing weight does not equate to improving body composition or health, as the scale does not differentiate between fat, muscle, and water. Initial weight loss often involves a decrease in glycogen and associated water, followed by fat loss. However, significant calorie deficits can lead to muscle loss, especially if protein intake is low and strength training is neglected. Studies show that medications like semaglutide and tirzepatide can result in muscle loss alongside fat loss, highlighting the need for strategies to preserve muscle during weight loss. The distinction between lean mass and muscle mass is crucial for understanding these effects.