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How to help your child gain weight

There could be several reasons your child or a child you care for is underweight. If it's because they're not getting enough calories there are things you can do to help.

It's important children get the right amount of calories, nutrients and minerals to support healthy growth.

The good news is that you can help them get more calories by making changes to what they eat and drink and encouraging healthy habits.

This information is for children aged 2 years old and over. If your child is under 2 years old, read about  weaning and feeding.


Check if your child is underweight

It can be difficult to know if your child is underweight. Growth spurts, illness and changes to their routine can have a big impact on their weight.

A good place to start is by calculating their body mass index (BMI).

Your child's result will be given as a centile (or percentile) and shows if they're a healthy weight for their gender, height and age.

You'll need to know their date of birth, height, weight and when you measured them.

Calculate your BMI for children and teenagers

Non-urgent advice: Speak to a GP or school nurse if:

  • you’re worried your child is underweight
  • they've lost weight quickly without changing what they eat and drink
  • you're worried about their eating habits
  • you think they have a food intolerance or allergy
  • things you're trying yourself are not helping

Tips to help your child gain weight


  • include more starchy carbohydrates such as potatoes, bread or rice in meals

  • increase their calorie intake with healthy fats – add grated cheese to meals and make porridge with milk

  • give them high-calorie drinks in between meals, such as milkshakes or smoothies

  • encourage a healthy attitude to eating – include them in the food preparation and try to eat together

  • have snacks available if they get hungry between meals – try yoghurts, breadsticks and small sandwiches

  • help them get enough vitamins by giving children aged from 6 months old to 5 years old vitamin A, C and D drops every day

  • introduce new foods gradually and in small portions – if they're a fussy eater this will help them get used to new foods


  • do not rely on unhealthy food for weight gain – swap cakes and crisps for a banana or cheese on crackers

  • do not give them drinks and snacks before eating – they might be too full to eat and will miss out on essential nutrients

  • try not to get frustrated if they do not eat everything on their plate – it might turn mealtimes into a negative experience

  • do not stop them exercising – physical activity will help them develop stronger bones and muscles

Further information

Over 100 child-friendly recipes

These recipes are nutritionally balanced and not specifically created for weight gain but you might find a new family favourite.

Visit the NHS Healthier Families website

The Eatwell Guide

Children from the age of 2 years old should start to follow the Eatwell Guide for a healthy, balanced diet.

The Eatwell Guide

Understanding fat

Fat is an essential part of a balanced diet. Find out how much is recommended and the difference between saturated and unsaturated fat.

Fat: the facts

Exercise guidelines

Like adults, children should try to reach a certain amount of daily, or weekly activity. Guidelines are different for each age group.

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Page last reviewed: 28 March 2023
Next review due: 28 March 2026