A consensus published in July in the scientific journal The Lancet Diabetes & Endocrinology, produced by three European entities dedicated to obesity and nutrition — the European Association for the Study of Obesity (EASO), the European Federation of the Association of Dietitians (EFAD) and the European Coalition for People with Obesity (ECPO) — warns that the rapid weight loss promoted by incretin-based drugs, including GLP-1 receptor agonists such as semaglutide (Ozempic and Wegovy) and dual GLP-1 and GIP agonists such as tirzepatide (Mounjaro), can bring not only nutritional and muscular risks but also psychological ones if patients focus only on weight loss and do not receive adequate follow-up. The experts reviewed all available literature up to 2025 and, for the first time, drew up practical recommendations for doctors, dietitians, psychologists and physiotherapists who accompany patients using these drugs.

According to the document, with the reduction in appetite, patients tend to consume less protein, vitamins, minerals and fibre. As a consequence, part of the weight loss can lead to loss of muscle mass, increase the risk of malnutrition and compromise functional capacity, especially among the elderly. During the weight-loss phase, the consensus recommends the intake of at least 60 grams of protein per day, distributed throughout meals. When diet is insufficient to reach this target, supplements such as whey and shakes may be considered. Another recommendation is to prioritise foods rich in fibre, at least 25 grams per day, which helps reduce constipation, one of the most reported adverse effects. In addition, consumption of 2 to 2.5 litres of water daily is recommended, since many patients lose thirst along with appetite, which can lead to dehydration.

The consensus also draws attention to the possibility of nutritional deficiencies. People with obesity often already have vitamin and mineral deficiencies before starting treatment, and the significant reduction in food intake can worsen this situation. The authors highlight the need to monitor nutrients such as iron, vitamin B12, vitamin D, folic acid and zinc in patients considered at higher risk. In situations where caloric intake remains below 1,200 calories per day, supplementation with multivitamins may be considered. Adverse effects such as nausea, vomiting, reflux, diarrhoea and constipation cannot be ignored.

Commenting on the publication, endocrinologist Fabio Moura, director of the Brazilian Society of Endocrinology and Metabology (Sbem), said: “The document came to highlight the importance of multidisciplinary treatment. Many people thought it was enough to use these drugs and everything was resolved. But it is no use losing weight any old way. It is important that this loss is with quality, to guarantee good health.” Nutrologist Guilherme Giorelli, professor and coordinator of the postgraduate course in Nutrology at Hospital Israelita Albert Einstein, said the publication responds to a relatively new reality in clinical practice: “We have never had such potent drugs to treat obesity. From one moment to the next, the patient who starts taking medication becomes more satiated and less hungry. This will, without a doubt, lead him to eat less. And whoever eats less needs to eat better. Much more attention is needed.”