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NHS Choices Condition

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The aim of treatment for obesity is to lose weight in order to improve your general quality of life, both physically and psychologically (see symptoms). For example, losing weight may help you sleep better, or help you to improve your self-esteem.

The best way to treat obesity is to reduce the amount of calories in your diet and to exercise more. The type of diet and exercise that will benefit you, and that you can follow safely, will vary from person to person. You should visit your GP before making any significant changes to your lifestyle.

Diet advice

A healthy diet should contain:

  • meals based on starchy, high-fibre
  • carbohydrates, such as wholegrain bread, pasta and rice,
  • at least five portions of fruit and vegetables every day,
  • a moderate amount of low-fat protein, milk and dairy products, and
  • a very small amount of foods that are high in fat, sugar or salt.

In order to lose weight, you need to eat a healthy diet and reduce the amount of calories in your diet. This will mean changing your eating habits. You need to do this a way that you find acceptable, and that you can maintain long-term (see tips for weight loss, in the box to the right).

Types of diet

Your GP may recommend a calorie controlled diet. This will be based on how much you are currently eating, and then attempting to cut the amount of calories you eat every day by around 600. Alternatively, you may be advised to follow a low-fat diet. See diet for tips to cut down the amount of fat and sugar in your diet.

A calorie controlled or low-fat diet should only be attempted with expert support and advice. You should also have a follow-up appointment with your GP to check your progress.

Low-calorie diets, for example those that aim for you to eat only 1000-1600 calories a day, may miss out some of the vital nutrients that you need to stay healthy. They may be recommended in some cases, but only with expert support.  

Diets that are very restrictive, for example those that cut out entire food groups, should not be used. This includes diets that cut out all carbohydrates or proteins. These diets are not usually sustainable in the long-term, and may be harmful. 

Further information

There is much more information on losing weight in the Live Well section of the website. This section contains information on:

Children and diet

As children are still growing, they may need to follow a special kind of diet to make sure that they are still getting all the nutrients they need to develop healthily. If your child is overweight or obese, consult your GP before making any significant changes to their diet.

Increase your exercise

Research suggests that increasing the amount of exercise you do is an effective way to lose weight, and the results are even better when combined with changes to your diet.

The advice from your GP about exercise will vary depending on how fit you are to start with, and what it is safe for you to do. You should start by decreasing the amount of time you are physically inactive, such as how long you spend watching television or sitting at a computer.

You should then build up slowly to 30 minutes of moderate intensity exercise on at least five days of the week. Moderate intensity means that you are breathing slightly more than normal, but you can still comfortably talk as you exercise.

Your 30 minutes of exercise does not need to be completed in a single session. If you prefer, it can be split into three 10 minute sessions. When you are able to, you should consider extending the amount of exercise to 45 minutes, and then keep increasing this as your fitness level improves. 

Types of exercise

The most effective types of exercise are ‘aerobic’ activities. Aerobic activities are any kind of rhythmic, moderate intensity exercises that use the large muscles in your legs and buttocks. The exercise should raise your heart rate and make you breathe harder. 

Recommended types of physical exercise include:

  • activities that can be incorporate into everyday life, such as brisk walking, gardening, or cycling,
  • supervised exercise programmes, and
  • activities such as swimming, walking (where you aim to walk a certain number of steps a day), and stair climbing.

Chose physical activities that you enjoy, as you are more likely to continue doing them.

Further information

For more information, see the fitness section of Live Well. This includes information on:

Children and exercise

Children should be encouraged to do at least 60 minutes of moderate activity each day. The activity can be in one session, or several sessions that last 10 minutes, or more. As with adults, children who are overweight, or obese, may need to do more than 60 minutes of exercise. You should check with your GP before your child starts a new exercise programme.


Medication for obesity may be available from your GP in some cases. You need to show you can lose weight on a calorie controlled diet before it is considered. Medication is normally one part of a weight loss programme, and requires a long-term change in lifestyle for lasting results.

The only medication currently prescribed is orlistat. See the box to the left for information on sibutramine, which is no longer used due to safety concerns.


Ortlisat works by blocking the action of an enzyme (a protein that speeds-up and controls chemical reactions in the body) that is used to digest fat. The undigested fat is not absorbed into your body, and is passed out with your faeces (stools). As you are absorbing less fat, you should lose weight.

One orlistat capsule is taken with each main meal (a maximum of three capsules a day). You can take the capsule either before, during, or up to one hour after each meal.

If you miss a meal, or the meal does not contain any fat, you may not need to take the orlistat capsule. Your GP should explain this to you, or you can check the patient information leaflet that comes with your medication.

You have to have made significant effort to lose weight through diet, exercise or changing your lifestyle before taking orlistat. Even then, orlistat is only prescribed if you are on a low calorie diet and you have:

  • a body mass index (BMI) of 28 or more, and other conditions related to weight, such as high blood pressure (hypertension), or
  • a BMI of 30 or more.

Treatment with orlistat must be combined with a low fat diet and other weight loss strategies, such as doing more exercise. If you are prescribed orlistat, you will also be offered advice and support about diet, exercise and making lifestyle changes.

Treatment with orlistat should only continue beyond three months if you have lost 5% of your body weight. Orlistat usually starts to affect how you digest fat within 1-2 days. If orlistat has not worked after three months, it is unlikely to be an effective treatment for you.

If you have type 2 diabetes (a condition caused by too much glucose in the blood), it may take you longer to lose weight using orlistat. Your target weight loss after three months may therefore be slightly lower.

If orlistat is successful after three months, your prescription may be continued for up to a year. After that, your GP will review your condition and decide whether you should continue with orlistat or not. 

Side effects and warnings

Side effects of orlistat include:

  • fatty or oily stools,
  • needing the toilet urgently,
  • passing stools more frequently,
  • oily discharge from your rectum (the storage area at the end of the bowel that holds the stools) - you may have oily spots on your underwear, 
  • flatulence (wind),
  • abdominal (stomach) pain,
  • headaches, and
  • upper respiratory tract infections - such as a cold or sore throat. 

Side effects are much less likely if you stick to a low fat diet.

Women taking an oral contraceptive pill are advised to use an additional method of contraception, such as a condom, if they experience severe diarrhoea while taking orlistat. This is because if you have diarrhoea, your contraceptive pill may not be absorbed by your body, and so may not be effective.

Orlistat is not prescribed to:

  • pregnant women,
  • breastfeeding women, and
  • children.

Children and medication

The use of medication to treat obesity is usually not recommended for children (under 18 years of age). In exceptional circumstances, for example if their obesity places their life in danger, orlistat may be considered for children over 12 years of age, with specialist supervision.

view information about Obesity on www.nhs.co.uk »

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