Obesity in adults

This factsheet is for people who are obese, or who would like to know more about obesity.

Obesity is a condition in which excess body fat affects a person's health. It usually happens because a person eats too many calories (energy) and doesn't do enough physical activity. Obesity increases the risk of a number of health problems including cancer, heart disease and type 2 diabetes.

About obesity
Complications of obesity
Causes of obesity
Diagnosis of obesity
Treatment of obesity

About obesity

If you regularly take in more calories (energy) than you use up, the extra energy is stored in your body as fat. You will start to gain weight and eventually become obese.

In 2008 around 1.5 billion adults worldwide were overweight and of these, over 200 million men and nearly 300 million women were obese.
 

Complications of obesity

If you're obese, you're at risk of developing health problems. These include:

• type 2 diabetes
• high blood pressure
• aching joints and osteoarthritis
• coronary heart disease
• some types of cancer
• sleeping problems, such as snoring and sleep apnoea
• back pain
• breathlessness

Women who are obese are more likely to have problems during and after pregnancy. If you're obese it can cause low self-esteem and poor body image.

Causes of obesity

Eating an unhealthy diet and lack of exercise are the main causes of obesity. Fatty foods, sweet foods and sugary drinks can cause weight gain if you eat or drink them often because they contain lots of calories. Large portion sizes can increase your chances of becoming obese.

If you were overweight or obese as a child, or if there is a history of obesity in your family, you're more likely to be obese as an adult. Genetic factors could play a role in this.

Occasionally medical conditions and medicines can make you put on weight.

Diagnosis of obesity

If you think you're overweight or obese, you should visit a doctor. He or she will ask you about your symptoms and may check your weight and height to calculate your body mass index (BMI). This may be used to work out if you're a healthy weight for your height. You can calculate your BMI by dividing your weight by your height, then dividing the answer you get by your height again.

If you have a BMI of:

• 25 to 29.9 – you're classed as overweight
• 30 to 39.9 – you're classed as obese
• over 40 – you're classed as severely obese

These BMI ranges aren't appropriate for everyone. For example, if you have a lot of muscle, your BMI may not be an accurate measurement of whether you need to lose weight.

If your BMI is less than 35, your doctor may also measure your waist. Carrying extra weight around your middle (an 'apple shape'), rather than your hips and thighs (a 'pear shape'), puts you at higher risk of obesity-related diseases. Your health may be at risk if you're a man with a waist measurement of 94cm (37 inches) or more, or a woman with a waist measurement of 80cm (32 inches) or more.

For certain ethnic groups, for example people of Asian descent, waist size is a better measure of the obesity-related health risks than BMI.

Your doctor may measure your blood pressure and offer a blood test to check your cholesterol and blood sugar levels. If you have health problems related to obesity, your doctor will provide the treatment you need.

Please note that availability and use of specific tests may vary from country to country.
 

Treatment of obesity

Losing weight takes time and effort so think about why you want to lose weight and whether you're ready to make changes.
If you have decided that you're ready to change, the best way to achieve a healthy weight is to improve your diet and eating habits, while increasing the amount of physical activity you do.

You're more likely to keep the weight off for good if you lose weight slowly. This allows time for new healthier eating habits to become part of your everyday life. It's important that you're realistic about the amount of weight you want to lose. The recommended rate of weight loss is 0.5 to 1kg (1 to 2 lbs) per week.

A healthy well-balanced diet

It's important that you follow a balanced diet and control portion size to maintain a healthy weight.

• Base your meals on starchy foods such as potatoes, pasta, bread and rice. You should choose wholegrain varieties if you can.
• Try to limit the amount of food high in fat and sugar, such as cakes, biscuits and butter. You should cut off any visible fat on meat and choose lean options.
• Introduce more fruit and vegetables into your diet so that you eat at least five portions a day. You could snack on fruit during the day and have a portion of vegetables with your evening meal.
• Aim for at least two portions of fish a week, including one of oily fish such as salmon, mackerel, or fresh tuna.
• Alcohol is high in calories and increases your appetite, so reducing the amount you drink can help control your weight.
• Water is the best drink. You could try flavouring water with low calorie squash or ice and lemon. Choose low sugar drinks instead of high calorie drinks.
• It's fine to snack, but choose healthy options such as fruit and low fat yoghurts. Snacking can help you manage your appetite so that you eat smaller portions at main meals.

Fad diets

A fad diet involves eating a very limited range of foods. These diets aren't healthy and although they may lead to short-term weight loss, you will always put the weight back on as soon as you return to your normal diet. There is no quick fix available.

Commercial weight-loss programmes

There are several commercial weight-loss programmes that can help you manage your weight. Slimming clubs are useful for people who like group meetings and prefer weekly support.

There are a range of online diet programmes available which can help you lose weight and maintain your weight loss. These may be more suitable if you're too busy to attend a group but you would benefit from social support via web chats and online discussion forums.

Talk to a doctor or nurse about which options would best suit your individual needs and fit in with your lifestyle.

Physical activity
You should aim to do some physical activity every day. The recommended healthy level of physical activity is 150 minutes (two and a half hours) of moderate exercise over a week in bouts of 10 minutes or more. You can do this by carrying out 30 minutes on at least five days each week. Alternatively, you can do 75 minutes of vigorous intensity activity.

Moderate means your breathing is faster, your heart rate is increased and you feel warmer. At this level of activity, your heart and lungs are being stimulated and this helps towards making you fitter. Vigorous intensity activity means that your breathing will be much stronger and your heart rate will increase rapidly. You will find it difficult to hold a conversation.
You may need professional supervision and if you're unsure then get advice from a doctor.

It's important that you find an activity you enjoy to help you stay motivated. If you find exercise boring on your own, invite a friend to join in with you or join a local club.

Medicines
If you have been following a healthy diet and increased your physical activity, but have still not seen any improvement in your weight, a doctor may prescribe a medicine called orlistat to help you lose weight. Orlistat stops your body absorbing all the fat from your food. It's recommended for people with a BMI of 30 or higher. If you have health problems associated with obesity, your doctor may prescribe you orlistat if your BMI is 27 or higher.

Your doctor will discuss any potential benefits and limitations of the medicine. You will also be given information about patient support programmes. It's important that you have regular follow-up appointments with your doctor.

Orlistat is also available over the counter. You need to talk to your pharmacist before he or she will sell it to you.

In January 2010 the European Medicines Agency suggested that the obesity medicine sibutramine (Reductil) may increase the risk of non-fatal heart attacks and strokes. The medicine has now been withdrawn from use within Europe.

Availability and use of medicines may vary from country to country.

Surgery
Occasionally, surgery is recommended for obesity. The most common types of surgery are gastric bypass and gastric banding.

They involve reducing the size of the stomach so that you eat less, or bypassing part of the gut so that your body absorbs less food. Surgery is recommended for people with obesity who:

• have a BMI of 40 or higher, or have a BMI between 35 and 40 with a disease that could be improved with weight loss (eg diabetes or high blood pressure)
• have tried other suitable ways of losing weight without any success
• are fit for surgery
• commit to a long-term treatment programme

If you have a BMI of 50 or more, surgery may be the first option. If your doctor recommends surgery, he or she will refer you to a specialist. The specialist will talk to you in more detail about the benefits and limitations of the surgery. Once the operation is completed, you will work with a specialist obesity team who will help you to make changes to your diet.

Availability and use of different treatments may vary from country to country. Ask your doctor for advice on your treatment options.