obesity

Glucagon-like peptide-1 (GLP-1) receptor agonist drugs, used to control obesity and type 2 diabetes, are associated with changes in food purchasing in favour of healthier options. This result, published in the journal JAMA Network Open, was obtained by analysing nearly two million shopping receipts from more than 1,100 participants in Denmark. Those who started treatment with GLP-1 drugs began to make purchases with fewer calories, sugars, saturated fats and carbohydrates, along with a modest increase in protein content. A decrease in the purchase of ultra-processed foods was also observed.

A higher body mass index (BMI) correlates—regardless of age at menarche—with a lower risk of breast cancer, according to a meta-analysis based on genetic data from more than 56,000 women. The study, published in Science Advances, seeks to clarify previous seemingly contradictory findings: more body fat (measured by BMI) before puberty could have a protective effect against breast cancer; however, a higher BMI is also linked to earlier menarche, which is associated with an increased risk of developing this disease. The authors indicate that the prepubertal stage is a ‘critical window’ in which adiposity has the greatest influence on future breast cancer risk.

Stopping weight loss drugs is followed by weight regain and reversal of beneficial effects on markers of cardiovascular and metabolic health, such as high cholesterol and high blood pressure, according to a meta-analysis published by The BMJ. The research includes 37 studies published up to February 2025 involving more than 9,300 people. 

An article published in Nature Medicine outlines the new framework for pharmacologically treating obesity and its complications established by the European Association for the Study of Obesity (EASO). The new guidelines establish semaglutide and tirzepatide as first-line treatment for this disease and most associated conditions. The team of authors, with Spanish participation, reviewed the scientific evidence on the effects of drugs on total weight loss and its complications and designed an algorithm to help medical personnel guide treatment, taking into account each patient's medical history and the action profiles of available medications.

An international team has analyzed data from 17 studies in 10 countries involving more than 9,000 participants and concluded that childhood obesity prevention programs focused on mothers and fathers do not appear to have an impact on young children. According to the authors, who published their findings in The Lancet, broader, coordinated, and well-resourced public health actions are needed.

In mice, administering semaglutide - the molecule marketed under the name Ozempic or Wegovy - does not reduce muscle mass as much as expected, but it does affect muscle function, according to a study published in Cell Metabolism. In some types of muscle, the experiment measured a decrease in force-generating capacity of about 20%, disproportionately greater than the loss of muscle mass.

Patients who are prescribed weight loss drugs may experience a rebound effect after stopping treatment, according to a meta-analysis published in BMC Medicine. The study, which analyses data from patients who received weight loss drugs in 11 randomised clinical trials, suggests that while the amount of weight regained varies depending on the specific drug, there is a general tendency to regain weight once treatment is stopped.

An analysis published in the medical journal The BMJ points out that lifestyle changes recommended by doctors to people with obesity, focusing on calorie restriction and increased physical activity, have little effect on long-term weight loss, fail to significantly reduce cardiovascular risks and, yet, can lead to discrimination, stigmatisation and eating disorders. The authors also point out that weight alone is an inadequate measure of a person's health, as reflected in recent clinical guidelines, and propose a ‘health for all sizes’ approach with effective, patient-centred care.

By 2030, there will be more than 1 billion adolescents (aged 10 to 24) living in countries facing preventable and treatable health issues. This figure represents half of the world’s adolescent population, according to a new analysis by the Lancet Commission on adolescent health and well-being. Among these health issues, the study highlights HIV/AIDS, early pregnancies, risky sexual behavior, depression, poor nutrition, and injuries.

Without urgent action and policy reforms, more than half of the world's adult population (3.8 billion) and a third of all children and adolescents (746 million) are expected to be overweight or obese by 2050. The figures are published today in The Lancet.