Obesity and healthy weight

This page provides general information about diet-related ill-health. For individual advice always seek guidance from a qualified health professional. 

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.

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:

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.  

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.

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.