- Weight loss from incretin drugs like semaglutide often causes more muscle loss than expected
- Muscle loss accounted for about 35% of total weight lost in incretin therapy groups
- Older adults face higher risks from muscle loss, including frailty and increased fall risk
A recent study from the University of North Carolina School of Medicine found that weight loss, especially from popular incretin-based medications like semaglutide and tirzepatide, often leads to more muscle loss than expected. The study was published in the journal Annals of Internal Medicine. It was led John A. Batsis, MD, an expert on obesity and nutrition at the UNC School of Medicine and the UNC Gillings School of Public Health. The study analysed multiple studies and found that muscle-related tissue accounted for about 35% of total weight lost in incretin groups, exceeding safe benchmarks in two-thirds of cases. While these drugs help with type 2 diabetes and obesity by lowering appetite and helping in weight reduction, the side effect is lean mass loss.
People with obesity usually have more muscle than normal-weight individuals, however, rapid weight loss reduces it without always preserving strength. In non-drug methods like dieting, muscle loss is around 2-10% for 8-10% body weight loss, but incretins increase the proportion. For older adults over 60, this can be dangerous as few trials include them. However, muscle loss can increase fall risks, frailty, and poor mobility. Batsis said, "While muscle loss is expected during weight loss, we observed that the proportion of weight loss attributable to muscle was consistently higher than anticipated across studies. These findings suggest that the magnitude of muscle loss relative to total weight loss warrants closer attention."
Study Findings
The review pooled data from 19 studies on incretin therapies versus non-drug approaches like diet or exercise. Median muscle loss was 35% of total weight reduction in drug groups, hitting or surpassing limits in 68% of trials. Half of the diet comparators also exceeded thresholds. Fat mass and visceral fat dropped as expected, but fat-free mass (FFM), including muscle, declined disproportionately. For example, semaglutide and tirzepatide users lost about 10% muscle over 68-72 weeks.
Why Does Muscle Loss Happen
Weight loss triggers muscle protein breakdown to fuel the body during calorie deficits, especially without resistance training. Incretins speed this by reducing intake by 16-39%, which hits the muscle alongside fat. Older adults lose more muscle due to lower muscle quality from obesity and age.
What Happens When You Lose Your Muscle Mass?
- Metabolic Slowdown: Muscle burns calories even at rest, so its loss lowers your basal metabolic rate. This makes weight gain easier and fat loss harder.
- Weakness and Frailty: Reduced muscle leads to frailty, affecting daily tasks like climbing stairs or carrying groceries. Everyday activities become exhausting, increasing your dependence on others.
- Risks of Injury: Weaker muscles increase chances of fall and fracture as they fail to stabilise the body. Bone density also reduces without muscle's pulling action during movement.
- Slower Recovery: Injuries heal slower due to poor repair capacity and inflammation. Post-workout soreness tends to linger for longer, discouraging exercise and worsening the loss.
- Health Complications: Muscle loss correlates with higher risks of hospitalisation, inflammation, and reduced quality of life. It predicts poorer longevity, morbidity, and even higher medical costs.
Ways To Prevent Loss Of Muscle Mass
Losing muscle mass can be prevented through lifestyle changes. These include resistance training, nutrition, and more.
Resistance Training
Engage in strength exercises like weightlifting, bodyweight moves (squats, push-ups, planks), or resistance bands at least twice weekly. These create muscle micro-tears that repair stronger, preserving mass during ageing or weight loss.
High-Protein Diet
Consume 25-40 grams of protein per meal from sources like lean meats, eggs, fish, dairy, beans, or whey; aiming for 1.2-1.6g per kg body weight daily. Leucine-rich foods like soy or meat trigger muscle protein synthesis, countering the breakdown.
Stay Active Daily
Combine aerobic exercise like walking and cycling with balance activities like yoga and tai chi to maintain function and prevent inactivity-induced atrophy.
Nutrient-Rich Foods
Consume fruits, vegetables, and anti-inflammatory diets like Mediterranean diet for vitamin D, omega-3s, and more, that support muscle health. These reduce inflammation and help in recovery without supplements.
Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.
