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Calories: Just The Facts

All food and drink contains calories.

Calories are a measurement of energy. We all need energy to keep our body working; without energy we would not be able to move, breathe, eat or keep our heart beating. We all have different requirements for energy.

The amount of calories you should eat a day depends on your age, gender and ethnicity. The calories you need will also depend on how active you are, your weight and your height. So a 14-year-old who exercises every day for 2 hours may need more than the recommended calories each day, but someone who isn’t very active might need less calories than recommended.

Wait a minute, what’s my weight?

You can see if you are a healthy weight by putting your height and weight details into the NHS BMI (Body Mass Index) calculator, which uses your height to see if you are a healthy weight.

The healthy range

You are having the correct calories for your body. This is keeping you in the healthy weight range.

  • Eat well: However, it is good to check you are eating a healthy balanced diet, have a look at The Eatwell Guide
  • Get your exercise: Try to be active for 60 minutes every day


Being underweight means that you are not eating enough for your height. This can leave you feeling low in energy, and can lead to health problems.

  • Feeling low? There are lots of reasons why you could be underweight. These include stress and emotional problems. It is always best to talk to someone about how you are feeling
  • Out of balance? Being a healthy weight depends on having the right balance between the calories we are putting in and those we are burning in energy. If you are underweight, it might be because you are not eating enough or because you are exercising too much. There may also be other reasons for being underweight, so talk to your school nurse or GP for more information
  • Re-balancing The first step to increasing your weight is to make sure that you are eating regular meals (breakfast, lunch, evening meal) and having 2-3 snacks per day. Use The Eatwell Guide to help you. Try snack foods like a scone with butter and jam or cheese and biscuits. If you are already doing this, then think about changing some of the foods and drinks you have. Go for the high fat/calorie options, and you could also try adding butter, margarine or cheese to vegetables, potatoes, rice or pasta.

For more information on being underweight, have a look at:


This means that you have more calories going into your body than you are burning off, which results in a slow gain of weight. If you are overweight, you can feel low in energy, and it can lead to health problems.

  • Start slowly balancing: The best way to reduce your weight is to decrease your calorie intake and increase activity; if you eat less calories than you need, you will lose weight. The most important thing to remember is to lose weight gradually. If you are still growing in height, then your ideal weight loss should be 1kg (2lbs) per month. OK, this doesn’t sound a lot, but if you think over a year that would be 12kg (1 stone, 12lbs). Just think, you didn’t wake up one morning to find your weight had increased – it happened over months and years
  • Don’t panic! For some young people, just keeping their weight the same is enough – as you grow taller, you will naturally become a healthier weight
  • Eat right: To help you manage your weight, think about what you are eating and drinking. Are you eating 3 meals (breakfast, lunch and evening meal) and having 1-2 planned healthy snacks everyday? Use The Eatwell Guide to help you. Skipping meals doesn’t help you lose weight – your body will slow down (its metabolic rate will decrease), need fewer calories to function and often crave high fat/sugar foods
  • Drink well: Don’t forget about drinks. You need to have 6-8 low-sugar drinks every day. If you don’t drink enough, you will often eat more so that your body can get the fluid from the food you eat to make up for the missing drinks. Try to go for low-fat/sugar options whenever possible, including drinks.

How to get help

If you have any more questions on this area or would like to speak to somebody about this topic, have a look at the links or search for your local services in the blue box below. Alternatively you can always contact your school nurse.

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