Diet and exercise before drugs, WHO says in its first guideline on adolescent obesity

Weight-loss drugs only for adolescents with complications such as type 2 diabetes, and only after six months of supervised diet and exercise fail.

Adolescents with obesity should be considered for weight-loss drugs only if they also have a related complication, such as type 2 diabetes, and at least six months of supervised lifestyle treatment has failed, the World Health Organization (WHO) said in its first guideline on the subject.

The WHO guidelines ask health workers to treat obesity and mental health 'early and together'. (Featured image: HT/Made on Canva)

For children under 10, the WHO does not recommend medicines, surgery or devices, it had said in a separate guideline for that age group.

The latest guideline covers young people aged 10 to 19 and was released in Geneva on Wednesday. It says such drugs should be prescribed by a team of specialists after "close evaluation of complete pubertal development, final adult height, and psychological stability".

The WHO rates the evidence behind the recommendation as low quality, and does not recommend a specific drug, but its guideline comes as glucagon-like peptide-1 (GLP-1) drugs, a class of weight-loss medicines, spread across markets worldwide.

India's drug regulator approved Novo Nordisk's semaglutide injection, sold as Wegovy, for adolescents aged 12 and above in May. Generic semaglutide has been on sale in India since the drug's patent expired in March.

"The foundation of obesity care for children and adolescents is not medicine or surgery, but access to comprehensive support that enables healthy eating, physical activity and sustainable behaviour change," Luz María De Regil, director of the WHO's Department of Nutrition and Food Safety, said in a statement.

Tailored to each teenager

Treatment starts with diet, exercise and habits. The WHO strongly recommends structured programmes covering all three, shaped around the young person's age, health, food preferences, culture and family support.

The key guidance:

• Food: No single diet is prescribed. Meals should be balanced and varied, with plenty of fruit, vegetables and pulses, less fat, and limited salt and sugar.
• Exercise: An average of at least 60 minutes a day of moderate to vigorous activity, fitted around school and friends. Non-competitive activities may suit some teenagers better.
• Habits: Setting goals, tracking eating and activity, and talking therapies such as cognitive behavioural therapy.
• Family: Parents or caregivers should be part of the treatment, and trained health workers should run it.
• Screens: Apps, fitness trackers and active video games may help, with a parent involved. The guideline cites Canadian advice linking more than two hours a day of recreational screen time to depression and poorer quality of life.
• Safety: Health workers should check whether the young person is at risk of an eating disorder before changing their diet.

The WHO acknowledges that the evidence behind these recommendations is weak. It backs them anyway, calling diet, activity and behaviour the "pillars" of obesity care that can be applied anywhere.

When do medicines and surgery come in?

The WHO says medicines can be considered for teenagers aged 10 to 19 only if three conditions are met:

• They have obesity and a related health problem, such as type 2 diabetes or uncontrolled high blood pressure.
• At least six months of supervised diet, exercise and behaviour change has not worked.
• A team of specialists prescribes the drug, after checking the teenager's growth, puberty and mental health.

The WHO calls the evidence behind this low quality and does not recommend a specific medicine.

But much of the interest is in GLP-1 drugs such as semaglutide and liraglutide, which mimic a gut hormone that signals fullness to the brain. Of the 31 placebo-controlled drug trials the WHO reviewed, five tested GLP-1 drugs. The trials it reviewed lasted between three and 16 months and were mostly in high-income countries. The guideline tells doctors to "consider the lack of evidence on long-term follow-up", and calls the field "rapidly evolving".

Surgery that changes the stomach or digestive tract may be considered only for teenagers with severe obesity, and only after the six-month programme has failed. It must be done in a specialised centre.

Is weight the only goal?

The WHO says care should aim to improve a child's health, functioning and well-being, with long-term follow-up, rather than measure success by the scales alone.

The guidelines ask health workers to treat obesity and mental health "early and together". The WHO says anxiety, depression, low self-esteem and difficulty regulating emotions can feed unhealthy eating, inactivity and withdrawal from friends. Children living with obesity also face stigma and bullying that can harm their emotional well-being.

Care, the agency says, should be inclusive, suited to the child's stage of development and involve the family.

"Treatment alone cannot reverse the rise in obesity," the WHO said in its statement. It called for policies that make healthy diets and physical activity cheaper and easier to reach, including regulatory and fiscal measures, and for action in schools, urban planning, transport and social protection.

The agency's fact sheet on obesity describes the condition as "a societal rather than solely an individual responsibility". It asks the food industry to cut fat, sugar and salt in processed foods and to restrict the marketing of such foods to children and teenagers.

Children, and obesity

About 170 million children and adolescents aged 5 to 19 were living with obesity in 2024, according to the WHO. They include 70 million aged 5 to 9 and 100 million aged 10 to 19.

The share of this age group with obesity has quadrupled since 1990, from 2% to 8%. Another 230 million are overweight, which brings the total carrying excess weight to 400 million, or one in five.

Obesity among the young is now rising faster in low- and middle-income countries and in rural areas than in the wealthy, urban populations it was once linked to, the WHO says. A 2026 study in Nature by the NCD Risk Factor Collaboration, a global network of health scientists, found that obesity rates have levelled off in rich countries and are accelerating in poorer ones.

In India, the share of children under five who are overweight rose from 2.1% to 3.4% between the fourth National Family Health Survey, conducted in 2015-16, and the fifth iteration of the survey, conducted in 2019-21.

Defining obesity

Adults are classed as obese at a body mass index (BMI) of 30 or more, according to WHO. BMI is a person's weight in kilograms divided by the square of their height in metres.

But a single cut-off cannot work for children, whose bodies keep changing as they grow.

For ages 5 to 19, the WHO compares a child's BMI with the median, or midpoint, for children of that age and sex in its Growth Reference. It measures the gap in standard deviations, a statistical unit of spread.

A child more than one standard deviation above the median is overweight, and a child more than two above it has obesity.

For children under five, the WHO uses weight-for-height instead. Overweight begins at two standard deviations above the median of its Child Growth Standards, and obesity at three.

Many Indian paediatricians use growth charts from the Indian Academy of Pediatrics, which set their own cut-offs.