Weight, obesity and cancer
With obesity cases on the rise, what’s the evidence about weight, obesity and cancer?
On this page
Keeping a healthy weight is important for your overall health now and in the future.
Being a healthy weight can help reduce your risk of some cancers, heart disease and type 2 diabetes, as well as improve your sleep and give you more day-to-day energy.
What’s the link between weight, obesity and cancer?
Our research shows that living with overweight or obesity can increase the risk of at least 13 different types of cancer, including:
- Bowel cancer
- Breast cancer (post-menopausal)
- Gallbladder cancer
- Kidney cancer
- Liver cancer
- Mouth, pharynx and larynx cancer
- Oesophageal cancer (adenocarcinoma)
- Ovarian cancer
- Pancreatic cancer
- Prostate cancer (advanced)
- Stomach cancer (cardia)
- Womb cancer
What’s the science behind weight and cancer?
Having too much body fat can cause inflammation and increase the levels of certain hormones in the body. These factors can increase the risk of cancer cells developing.
While living with overweight or obesity doesn’t mean you will get cancer, it does increase your risk, compared with if you were a healthy weight.
That’s why as part of our Cancer Prevention Recommendations, we recommend that people be a healthy weight.
What is a healthy weight?
Your body weight is unique to you and can be influenced by many different factors, such as your genetics, whether you are taking certain medications, your environment and your lifestyle. These may make it harder for some people to lose weight.
To check if you are in a healthy weight range and whether you are at a higher health risk, you can:
- Calculate your body mass index (BMI) – it’s a simple way to check if you are a healthy weight for your height.
- Measure around your waist – this can help you determine if you have too much fat around your waist and whether you are at a higher health risk.
Maintaining a healthy weight
We have strong scientific evidence that the following can help you maintain a healthy weight:
- Keeping physically active, like brisk walking. Aim for at least 20–30 minutes a day.
- Eating high-fibre foods such as fruit, vegetables, wholegrains (such as brown rice), pulses (eg chickpeas and lentils), nuts and seeds.
- Eating a “Mediterranean-type” diet, which typically includes high-fibre foods, olive oil, and moderate amounts of fish, poultry and dairy, and small amounts of red meat.
To incorporate these into your daily life, consider setting small, achievable goals, like adding an extra serving of vegetables to your meals or taking a walk during your lunch breaks.
Equally, we have strong evidence that the following can increase the risk of weight gain:
- Too much screen time, like watching TV, as it’s associated with being inactive and eating unhealthier foods without thinking. That’s why it’s a good idea to limit your screen time and take breaks to move around every 30 minutes.
- Regularly drinking sugary drinks, like cola. Choose sugar-free alternatives and have water as your go-to drink.
- Regularly eating “fast food”, like fried chicken and chips. Try cooking more homemade meals using a variety of plant-based foods and lean meats.
- Eating a “Western-type” diet, which typically includes a high amount of red meat and processed food high in fat, sugar and salt.
By making one change at a time, you can support your health now and in the future.
Download our free Weight matters guide for more information and practical tips to help you lose and maintain a healthy weight.
Healthy weight loss tips
1. Avoid fad diets
A “fad” diet typically involves eating very little food or only certain types of food. They usually promise quick weight loss but lack strong scientific evidence.
When you go back to eating normally, the weight you have lost often comes back quickly, and you might gain even more weight.
Instead, it’s best to eat a healthy, balanced diet that includes food you can enjoy and that can be maintained in the long-term.
2. Reshape your plate
Fill 3/4 of your plate with fruit, vegetables, wholegrains, pulses, nuts and seeds. The remaining 1/4 should be for protein sources such as plant-based protein (eg tofu), eggs, low-fat dairy, skinless poultry or fish.
Try to reduce the amount of “fast” food and processed food and drinks that are high in fat, sugar and salt in your everyday diet.
3. Read food labels
Food labels include useful information that can help you make healthier choices. Use the front-of-pack traffic light label (if it has one) to check if a food is high, medium or low in fat, saturated fat, sugar and salt.
You can also use food labels to compare calorie content between similar products and see how many servings are in a pack.
> For more guidance on food labels, download our Making sense of food and drinks labelling guide
4. Get familiar with portion sizes
Even if you are making healthier choices, eating and drinking too much can lead to weight gain if you are eating and drinking more calories than your body needs.
That’s why it’s important to know what a healthy portion size looks like for different foods.
> To learn about healthy portion sizes, download our free poster: What is a healthy portion size?
5. Be more active
Keeping physically active can help you to maintain a healthy weight by helping your body burn calories.
Aim for 20-30 minutes a day and reduce how much time you spend sitting down.
Living with cancer
After a cancer diagnosis: follow our Recommendations, if you can.
If you’re undergoing cancer treatment, you may experience weight changes – perhaps you are losing weight from a lack of appetite or gaining weight from taking certain medications.
If you’re having trouble with your weight, talk to your cancer care team for personalised advice and support.
Further research
Read the chapters from our 2018 Third Expert Report:
> Download the chapter on body fatness and weight gain and cancer
> Download the full chapter on the determinants of weight gain, overweight and obesity
More useful information
Preventing cancer. Saving lives
While society continues to search for a cure, our prevention and survival work helps people to live longer, healthier lives – free from the devastating effects of cancer.