Doctors warn of a decline in health as a side effect of weight loss - Jornal O Sul

Doctors warn of muscle mass as a result of weight loss - Jornal O Sul

Sunday, April 12, 2026

By Redação O Sul |Eprel 6, 2026

No revolution is without problems.One of the main causes of weight loss is muscle loss.This can be seen in the flabby "Olympic faces and bodies" of social media.People "melt away" because they lose a lot of muscle along with fat.However, flabbiness is the visible and less serious face of a much bigger problem: loss of muscle mass.

The pens provide an average weight loss of 20% in about a year.But not everything is fat.In some cases, up to almost half is muscle.

"Muscle loss is a crucial point in the use of pens," says Lício Velloso, an obesity expert at the University of Campinas (Unicamp).

Loss of muscle mass is not only a cosmetic problem.It affects mobility, metabolism, strength, immunity and cognition.The massive reduction in muscle mass has the effect, generally speaking, of accelerating aging.Significant loss of muscle mass is not directly caused by drugs, but by rapid weight loss.

Clayton Macedo, coordinator of the Exercise Endocrinology Clinic of the Federal University of São Paulo (Unifesp) and member of the Brazilian Society of Endocrinology and Medicine, this is not a reason for anyone to stop using drugs with a medical recommendation, but to do it correctly.The right way is with medical advice, protein diet and physical activity.

"Loss of muscle mass" is one of the most troublesome factory. We have young people who develop sarcopenia (severe loss of muscle mass, almost always aging) due to the use of these drugs without proper control", Cynthia Valerio, president-elect of the Brazilian Association for the Study of Obesity and Metabolic Syndrome (Abesa).

The author of studies on the subject, Carla Prado, director of the Human Nutrition Research Unit at the University of Alberta, in Canada, warns that low muscle mass is associated with a higher risk of mortality from a number of diseases, starting with cardiovascular diseases.

And the wave of muscle loss is so worrying that more and more pharmaceutical companies are developing drugs to stimulate muscle growth.

scale of problem

Loss of muscle mass ranged from 25% to 39% of total body weight lost over 36-72 weeks."This large amount of muscle loss is mostly due to the magnitude of weight loss, not an independent effect of GLP-1 receptor agonists, although this hypothesis needs to be tested," says an article led by Carla Prado, in Lancet Diabetes & Endocrinology.

"They are revolutionary drugs for weight loss, but they are not made for everyone. People really lose a lot of muscle", emphasized Prado.

Jose Donato Jr., head of the Neuroendocrinology and Metabolism Laboratory at the University of São Paulo (USP).said there were no errors.There is a physiological limit to fat loss per week.The rest of the weight lost is too lean.

Prado points out that it is a fallacy to say that the loss of muscle mass is not so important because it is part of the lean mass, which also contains water, connective tissue, for example.Muscles represent about 50% of lean mass.That's a lot.And so, the loss of lean mass reflects the loss of muscle mass, Prado says.

There is no medicine that causes this kind of loss.Low calorie diet results in 14% muscle loss.Very low calorie foods, like 23%, but these foods are almost impossible to maintain.Bariatric surgery shows a weight loss of about 21%, Prado said.

Loss of muscle mass is greater than expected with aging (0.8% per year based on 8% muscle loss per decade between ages 40 and 70).

Num exemplo, um homem de 50 anos, com 110 kg iniciais (35 kg de músculo esquelético) que use semaglutida por 68 semanas e perca 20 kg (18% do peso) terá perdido 15 kg de gordura e 5 kg músculo (25% da perda total, o equivalente a cerca de 14% da sua massa muscular inicial).

A taxa natural média de perda de massa muscular na faixa dos 50 anos é de 0,5% a 1% da massa muscular/ano. Isso equivaleria a perder em cerca de um e três meses o que seria esperado em nove anos de envelhecimento.

Why are muscles important?

Skeletal muscles do more than allow support and all kinds of body movement.They are important in preventing and controlling inflammation and diseases as diverse as cancer, diabetes, dementia and bone loss.

"Muscles are our last resort in post-surgical infection, trauma and recovery," added José Cesar Rosa Neto from the Immunometabolism Laboratory (USP) at the University of São Paulo.

Around 700 skeletal muscles make up the largest endocrine system in the body.They produce at least 650 substances, many of them hormones and other proteins important for metabolism, the brain and immunity.The immune system stores amino acids in the muscles when, for example, we get an infection.

Who is most vulnerable

People of the same weight can have different muscle composition.The less muscle, the worse the result.Sedentary people will have a greater loss than those who engage in physical activity.

People who are not overweight, and even thin people who seek to satisfy their aesthetic desires, pay some of the muscle loss.They don't have much fat left to lose.Aesthetic use is a concern because people lose the necessary muscles, explains José César Rosa Neto.

Patients with body mass index greater than 27 and comorbidities and obesity (more than 30) are appropriate indications.

“Those who have medical supervision, follow an adequate diet and practice physical exercise do not suffer major losses”, says Macedo.The news is from the newspaper O Globo.

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