How to Prevent Childhood Obesity

Children are growing, so "losing weight" is rarely the goal. The aim is to slow weight gain while a child grows into their weight, and to build habits the whole family can keep. That is a different job from adult dieting.

How is childhood obesity defined?

WHO uses growth standards rather than a single number. For children and teenagers aged 5 to 19, overweight is a body mass index for age more than 1 standard deviation above the WHO reference median, and obesity is more than 2 standard deviations above it. For children under 5, overweight is weight-for-height more than 2 standard deviations above the WHO standard, and obesity more than 3. Only a health worker plotting a growth chart can tell.

How common is it?

WHO reports that in 2022 more than 390 million children and teenagers aged 5 to 19 were overweight, including 160 million living with obesity. Among that age group, prevalence rose from 8% in 1990 to 20% in 2022.

What is driving it?

WHO points to eating patterns high in fat, sugar and salt that are energy-dense but poor in vitamins and minerals, combined with falling levels of physical activity. WHO notes this now affects low- and middle-income countries too.

Why act early?

WHO says childhood obesity is linked to greater risk and earlier onset of long-term conditions such as type 2 diabetes and heart disease. WHO also notes effects that are easier to overlook: stigma, discrimination and bullying, which affect a child's school performance and quality of life. Handle the subject gently, and never in front of others.

What can a family actually do?

WHO's advice is to limit sugar-sweetened drinks and energy-dense foods, limit energy from total fats and sugars, eat more fruit, vegetables, pulses, whole grains and nuts, and be physically active regularly. The NHS turns this into daily habits:

• Serve child-sized portions. The NHS advises not giving adult-sized portions, using smaller plates, starting with small servings and letting a child ask for more if still hungry.
• Change the drinks. Swap sugary soft drinks, juice and flavoured milks for water and lower-fat milk.
• Aim for 5 A Day. The NHS says children, like adults, should eat five or more portions of a variety of fruit and vegetables daily.
• Cut back on sweets, cakes, biscuits, crisps and chocolate rather than banning them completely.
• Be the example. The NHS says parents can be good role models by staying active and eating healthily themselves.

How much activity and sleep do children need?

The NHS says school-aged children need about 60 minutes of physical activity a day, and children under five need more than three hours a day. The CDC agrees on 60 minutes daily for ages 6 to 17, and adds detail: most of it should be aerobic, such as walking or running; vigorous activity on at least 3 days a week; muscle-strengthening activity such as climbing or push-ups on at least 3 days; and bone-strengthening activity such as jumping or running on at least 3 days. Children aged 3 to 5 should simply be active throughout the day.

Screens and sleep matter too. The NHS says children should have no more than 2 hours of screen time a day, that children who do not get the recommended amount of sleep are more likely to be overweight, and that a regular bedtime routine with screens removed from the bedroom at night helps.

When to see a doctor

Speak to a health worker before any big change, especially if your child:

• Is gaining weight quickly or crossing upwards through lines on the growth chart.
• Is losing weight, or is not gaining weight as expected.
• Is refusing meals, skipping meals secretly, or seems anxious about food or body shape.
• Is being bullied, withdrawn or low in mood.
• Is too breathless to join in play with other children.

Do not put a growing child on a weight-loss diet, use weight-loss products, or start supplements on your own. Ask a doctor to check your child first. If a child has chest pain, severe breathlessness or collapses, call Rescue 1122 where available, or go to the nearest hospital emergency department.