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Obesity and healthy weight

What is obesity?

Overweight and obesity are defined as abnormal or excessive fat accumulation that presents a risk to health. A body mass index (BMI) over 25 is considered overweight, and over 30 is obese.


In England, almost 7 in 10 men and 6 in 10 women are overweight or obese, and a quarter of adults are obese. Being overweight or obese increases your risk of developing serious diseases such as type 2 diabetes, coronary heart disease and some cancers. The risk of developing these diseases increases, the more overweight you are.


Obesity can also affect your quality of life and lead to psychological problems, such as depression and low self-esteem. Ideally it is better to avoid becoming overweight by eating healthily and exercising regularly and maintaining this throughout life. But for many of us, our weight increases over time and it can be challenging to get back to a healthy weight.


Problems with weight gain are common. So, in this article, we share useful information to help you lose weight sensibly and healthily.


There is no ‘quick fix’ for obesity. Weight loss takes time and commitment. However, even losing and keeping off even a small amount of weight can produce health benefits and reduce your risk of developing obesity-related diseases.



Zoe Hill, Nutrition Scientist, British Nutrition Foundation

What is a healthy weight?

To see if you have a healthy weight you can use a measurement called your body mass index, or BMI. This BMI calculator uses your age, sex and height to work out if you are a healthy weight.


For most adults:

  • A BMI between 18.5 and 25 is defined as healthy.
  • A BMI of over 25 is defined as overweight.
  • A BMI of over 30 is defined as obese.

Your waist measurement (waist circumference) can also be used to check your risk of obesity-related diseases (including heart disease, type 2 diabetes and cancer). These conditions are affected by where your body fat is stored, as well as by your weight. People who are very muscular sometimes have a high BMI without excess fat. For these people, waist circumference may give a better indication of whether they have excess fat. To measure your waist circumference, measure around your middle at a point half-way between your lower rib and top of your hips.



Waist circumference where there is an increased or high risk of obesity-related health problems:


Increased risk 

High risk


≥94cm (37in)

≥102cm (40in)


≥80cm (31.5in)

≥88 cm (34.5in)


What's considered a healthy BMI and waist circumference is also influenced by your ethnic background. For people of African Caribbean, South Asian, Chinese and Japanese origin there are lower thresholds for increased risk. This is because people from these ethnic backgrounds tend to carry more fat and less muscle compared to people from a white European background.  

Health benefits of losing weight

Weight loss can reduce your risk of heart disease, stroke, type 2 diabetes and some cancers.

It can also reduce the risk of:

  • High blood pressure
  • Angina (heart condition causing chest pain)
  • High blood cholesterol levels
  • Lower back and joint pain
  • Fertility problems

How do I lose weight sensibly?

At a very basic level, your body weight is determined by the amount of calories you get from your diet compared to the amount of calories that your body uses. Excess calories consumed from food and drink are stored as fat. To lose weight, the energy you take in from food must be less than the energy you use. 


Although this sounds simple, it is not easy to achieve. In our society, high calorie, tasty foods are readily available and we have to make a conscious effort to be active. This environment makes it easy for us to eat more than we need and challenging to make healthier choices and have a balanced diet. 


Sensible weight loss should be seen as a long-term lifestyle change, which involves eating a healthy, balanced diet and doing plenty of physical activity. Generally, guidelines recommend that you should try to lose weight gradually, about 1-2lbs (approximately 0.5-1.0kg) a week. This way, the weight is more likely to stay off. This rate of weight loss is based on using up about 600 calories per day more than you take in. On average, this means consuming no more than 1400 calories a day if you are a woman, and no more than 1900 calories a day if you are a man. 


Different approaches to weight loss will be successful for different individuals, so try to find a weight-loss plan which will work for you. Calorie and portion size control is an important part of a weight loss strategy, but success is likely to depend on how well you can stick to your plan more than it's composition (whether it’s low carb or low fat, for example). 


It has been shown that weight loss plans which provide some form of social support are easier to stick to, compared to those which do not. This could be as simple as having a ‘buddy’ to take part in physical activity with you, joining an online weight-loss community or attending organised weight-loss programme meetings in your area.


The NHS has a free online 12-week weight-loss plan, which includes handy tips, a weight-loss forum and email support. Find out more on the NHS website. You can also talk to your GP or pharmacist to see which services are available in your local area.

11 dietary tips for healthy weight loss

  1. Avoid fad diets that recommend unsafe practices - such as going without food for long periods of time or cutting out entire food groups. Sticking to these types of diets in the long run is difficult, meaning the chances of meeting your long-term bodyweight goals may be reduced. If you have type 2 diabetes and are considering a low-carbohydrate diet, speak to a health professional (such as a GP or dietitian).
  2. Decrease the number of foods and drinks you are consuming that are high in fat or sugars - to do this, you could try limiting sugars-containing drinks, fried foods, cakes, biscuits and desserts in your diet. These should be thought of as occasional treats, eaten in small quantities, rather than everyday occurrences. Try swapping them for healthier alternatives lower in fat and/or sugars.
  3. You should eat plenty of fruit and vegetables (at least 5 A DAY).
  4. Boil, steam, grill, poach or microwave food rather than frying - If roasting, use a small amount of an oil high in unsaturated fat (such as olive or rapeseed oil).
  5. Choose lean cuts of meat, leaner mince and trim off the fat from meat and skin from poultry.
  6. Eat more beans and pulses - these are good alternatives to meat as they are low in fat and high in fibre and still a good source of protein.
  7. You should try to opt for ‘reduced fat’ or ‘low fat’ versions of dairy foods - such as reduced fat cheese and low-fat yogurt. Switch to a lower fat milk (skimmed, semi-skimmed or 1% milk) if you have not already done so.
  8. Read the nutrition information on food labels - this will help you choose foods which are lower in fat, sugars and calories. The traffic light colours on the front of product packaging show whether the product has a high (red), medium (amber) or low (green) amount of fat, saturates, sugars and salt. Try to eat more greens and ambers and fewer reds.
  9. Watch your portion sizes - keep an eye on the portion sizes you serve at home and avoid situations where you know you may be tempted to overeat.
  10. Go wholegrain - choosing wholegrains such as wholemeal bread or pasta, adds extra fibre, which may help you to feel fuller.
  11. Moderate the amount of alcohol you consume - alcohol has calories too. These count towards your total energy intake each day. For example, a pint of lager has about the same calorie content as a packet of crisps. If you drink alcohol, try alternating your drinks with a glass of water, opt for a lower alcohol beverage, or dilute alcoholic drinks with sparkling water or sugar free mixer.

Physical activity

There is evidence to show that people who combine regular physical activity with a healthy eating plan are more successful at losing weight and keeping it off.


The Government recommends at least 150 minutes of moderate-intensity aerobic activity or 75 minutes of vigorous intensity aerobic activity a week (or a combination of both). It also recommends muscle strengthening activities on two days or more of the week.


Keeping active increases the amount of calories you use, builds muscle , and helps maintain weight loss. Physical activity also reduces the risk of weight loss reaching a plateau level, which is often seen when people are trying to lose weight. If you are not used to physical activity, you should first aim to gradually build up to 150 minutes of moderate intensity activity per week. As your fitness increases, you can then increase your level of physical activity beyond 150 minutes and start to include more vigorous intensity exercise. As well as helping with weight control, keeping active has many other benefits including reducing risk of heart disease, improving sleep, and helping to manage stress.

Here are some tips to increase your physical activity:

  • Find a type of physical activity you enjoy, this can be anything from walking the dog, dancing, gardening, going to the gym or playing a team sport. The more you enjoy it, the more you are likely to do.
  • Exercise with a friend and use each other for motivation.
  • Try to make physical activity part of your daily routine, such as walking to work and taking the stairs instead of the lift.
  • Do not set yourself unrealistic targets; not everyone will be able to run a marathon!

For more tips on increasing your physical activity read our page on activity in daily life.

Thinking of trying to lose weight?

Here are some things to consider first:

  • It is not advisable to lose weight whilst pregnant. Find out more information by reading our page on a healthy weight during pregnancy.
  • Parents/carers of children who are overweight or obese should seek advice from a health professional about what you can do and what support is available in your area.
  • If you suffer from any medical condition, you should always ask your GP before starting a weight loss plan.
  • It is important to maintain a healthy weight. Weight loss which results in somebody being underweight can also cause health problems. Boys, girls, men and women from all backgrounds and ethnic groups can be affected by eating disorders. If you think you, or somebody you know, may have an eating problem or disorder, help is available. Find more information on the Beat website.

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Please note that advice provided on our website about nutrition and health is general in nature. We do not provide any individualised advice on prevention, treatment and management for patients or their family members.