https://www.gosh.nhs.uk/conditions-and-treatments/general-health-advice-children/eat-smart/obesity-lowdown/gaining-weight/
Gaining weight
It’s now very easy for children to become overweight. Being overweight is rarely to do with a medical problem. Many kids have unhealthy diets and don’t do enough exercise. This means weight goes on easily. Reasons why obesity is more common these days:
- Junk food is everywhere and is easy and cheap to buy.
- People are less active now and use cars and take lifts and escalators.
- Children are doing less sport at school.
- Food portion sizes are getting bigger.
- Food now tends to have more calories in each mouthful.
- Shops and supermarkets stock lots of high-fat, sweet and salty foods which people naturally like.
- Kids are sitting down more. They're watching more and more television and playing computer games.
So, whenever we take in more food than the energy we burn up by being active, our bodies stores the extra as fat. This is how people put on weight.