Healthy weight and cancer prevention

Does your weight affect your risk of cancer?

Many people are surprised to find out that being overweight or obese increases your risk of common cancers like bowel and breast cancer.

There is strong evidence that being overweight or obese increases the risk of developing 11 different types of cancer:

We could prevent about 1 in 6 of these cancer cases – that's about 25,000 cases a year – if we were all a healthy weight. In fact, after not smoking, being a healthy weight is the most important thing you can do to reduce your cancer risk.

Being a healthy weight can also help to reduce your risk of heart disease and Type 2 diabetes.

What is a healthy weight?

Your weight is a balancing act between the energy you put in (calories from foods and drinks) and the energy you use (for normal bodily functions and what you burn during physical activity).

The average adult man needs around 2,500 calories a day, and an average woman needs about 2,000 calories. If you eat or drink more than your body needs, you will put on weight. The reverse is also true: if you regularly use more energy than you take in, you will start to lose weight.

Checking your Body Mass Index (BMI) is a simple way to find out whether you’re a healthy weight for your height. A healthy BMI for men and women is between 18.5–24.9.

Carrying too much fat around the waist is also linked to a greater risk of cancer, heart disease and Type 2 diabetes, so measuring your waist is a good way to check if you are a healthy shape. A healthy waist measurement is less than 94cm/37 inches for men and less than 80cm/31.5 inches for women.

How does body weight increase cancer risk?

Our research shows there are several reasons for the link between body fatness and cancer.

For example, we know that fat cells release hormones such as oestrogen, which increases the risk of some cancers, like breast and womb cancer, and promote their growth.

Storing too much fat also encourages the body to produce ‘growth hormones’. High levels of these hormones can promote the growth of cancer cells.

Body fat also stimulates an inflammatory response, which may contribute to the development of several cancers.

Tips to help you stay a healthy weight

Taking a few simple steps can make all the difference. If you’re overweight, losing even a few pounds will make a positive difference to your health.

  • Reshape your plate

Feel fuller on fewer calories by swapping high-calorie processed foods such as biscuits, cakes, crisps and fast foods like pizza, chip and burgers, for fibre-rich wholegrains, vegetables, pulses and fruit. Get inspired by our healthy recipes.

  • Keep an eye on portion sizes

Too much of almost any food can cause you to gain weight, so only eat when you’re hungry and opt for smaller serving sizes to make it easier to control how much you’re eating. Take a look at our portion size poster to see what is a healthy portion of different foods.

  • Read food labels

Food labels include lots of useful information to help us make healthier choices. Use the front-of-pack traffic light label to see, at a glance, if a food is high, medium or low in fat, sugar and salt. You can also use food labels to compare calorie content and see how many servings are in a pack.

  • Be more active

Keeping active helps burn calories, which are stored as fat if they are not used. Why not sign up for a running event to help keep you motivated?

For more information and tips, download our free Be a Healthy Weight booklet.