1. Be as lean as possible without becoming underweight.
Maintaining a healthy weight is one of the most important things you can do to reduce your risk of cancer. Aim to be at the lower end of the healthy Body Mass Index (BMI) range.
Maintaining a healthy weight brings an array of health benefits. As well as making us feel better, it also means that we are less likely to develop not only cancer, but also other chronic diseases such as type 2 diabetes and heart disease.
We also know that where we store extra weight affects cancer risk. Scientists have discovered that carrying excess fat around our waists can be particularly harmful – it acts like a ‘hormone pump’ releasing estrogen into the bloodstream as well as raising levels of other hormones in the body. This is strongly linked to colon cancer and probably to cancers of the pancreas and endometrium (lining of the uterus), as well as breast cancer (in postmenopausal women).
See Recommendations 2 and 3 for strategies for weight management.
2. Be physically active for at least 30 minutes every day.
Physical activity in any form helps to lower cancer risk. Aim to build more activity, like brisk walking, into your daily routine.
Limit sedentary habits, such as watching television.
As well as helping us avoid weight gain, activity itself can help to prevent cancer. Studies show that regular activity can help to keep hormone levels healthy, which is important because having high levels of some hormones can increase your cancer risk.
Physical activity may also strengthen our immune system, help keep our digestive system healthy and allow us to consume more food and more cancer-protective nutrients – without gaining weight.
If you’re not used to doing much activity, start by working toward 30 minutes of moderate activity each day – remember that anything is better than nothing. You can build up slowly until you reach your target. Shorter bouts of activity are just as beneficial. (It’s the total time that’s important.)
Research shows that to avoid weight gain, doing more activity is beneficial. High amounts of sitting – sedentary behaviors – also links to overweight and obesity. Moving more throughout the day and limiting sedentary behaviors may help with weight control.
For maximum health benefits, scientists recommend that we aim for 60 minutes or more of moderate activity every day, or 30 minutes or more of vigorous activity.
Moderate and Vigorous Activity
Moderate activity is anything that gets your heart beating a bit faster and makes you breathe more deeply – like brisk walking.
Vigorous activity means raising your heart rate so that you warm up, start to sweat and feel out of breath.
3. Avoid sugary drinks. Limit consumption of energy-dense foods (particularly processed foods high in added sugar, or low in fiber, or high in fat).
Choosing healthy foods and drinks instead of those that are high in refined carbohydrates and often in added sugar and fat (energy-dense foods) can help us avoid overweight and obesity and thereby reduce our cancer risk.
What are energy-dense foods?
Most foods provide us with energy (calories), but some foods contain more energy ounce-for-ounce than others. Energy-dense foods tend to be processed foods with sugar and fat added to improve the taste. The result is more calories per ounce.
For example, 3.5 oz. of chocolate contains 10 times more calories than the same amount of apple:
3.5 oz. of milk chocolate = 520 calories
3.5 oz. of apple = 52 calories
It can be difficult to control how much energy you are consuming if you eat a lot of energy-dense foods because you only need to eat a small amount to take in a lot of calories. It’s okay to eat energy-dense foods occasionally, or in small quantities, but try not to make them the basis of your diet. By choosing a diet based on low-energy-dense foods, you can actually eat more food but consume fewer calories.
Foods that are low in energy density, like the apple, are high in fiber and water. Most vegetables, fruits and beans fall into the low-energy-dense category. It is yet another reason to base your diet on plant-based foods.
Sugary drinks and weight gain
The expert report found that regularly consuming sugary drinks contributes to weight gain. These drinks are easy to drink in large quantities but don’t make us feel full, even though they are quite high in calories. Sugary drinks include: soft drinks like colas and juice flavored drinks. We should try to avoid these drinks.
Water is the best alternative. Unsweetened tea and coffee are also healthy options. Natural fruit juice counts as one of our recommended 5 or more daily portions of vegetables and fruits, but it does contain a lot of sugar. It’s best not to drink more than one glass a day.
4. Eat more of a variety of vegetables, fruits, whole grains and legumes such as beans.
Basing our diets on plant foods (like vegetables, fruits, whole grains and legumes such as beans), which contain fiber and other nutrients, can reduce our risk of cancer.
For good health, AICR recommends that we base all of our meals on plant foods. When preparing a meal, aim to fill at least two-thirds of your plate with vegetables, fruits, whole grains and beans.
Research shows that vegetables and fruits probably protect against a range of cancers, including mouth, pharynx, larynx, esophagus, stomach, lung, pancreas and prostate. There are many reasons why vegetables and fruits may protect against cancer. As well as containing vitamins and minerals, which help keep the body healthy and strengthen our immune system, they are also good sources of substances like phytochemicals. These are biologically active compounds, which can help to protect cells in the body from damage that can lead to cancer.
Foods containing fiber are also linked to a reduced risk of cancer. These foods include whole-grain bread and pasta, oats and vegetables and fruits. Fiber is thought to have many benefits, including helping to speed up ‘gut transit time’ – how long it takes food to move through the digestive system.
Plant foods can also help us to maintain a healthy weight because many of them are lower in energy density (calories).
5. Limit consumption of red meats (such as beef, pork and lamb) and avoid processed meats.
To reduce your cancer risk, eat no more than 18 oz. (cooked weight) per week of red meats, like beef, pork and lamb, and avoid processed meat such as ham, bacon, salami, hot dogs and sausages.
Red meat refers to beef, pork and lamb–foods like hamburgers, steak, pork chops and roast lamb. The term processed meat refers to meats preserved by smoking, curing or salting, or by the addition of preservatives. Examples include ham, bacon, pastrami and salami, as well as hot dogs and sausages.
The evidence from the expert report that red meat is a cause of colorectal cancer is convincing. This evidence is much stronger now than it was in the mid-1990s. Red meat contains substances that are linked to colon cancer. For example, heme iron, the compound that gives red meat its color, has been shown to damage the lining of the colon.
Studies also show that people who eat a lot of red meat tend to eat less plant-based foods, so they benefit less from their cancer-protective properties.
There is also convincing evidence that choosing processed meat increases the chances of colorectal cancer. The expert panel advises limiting red meat and avoiding processed meat. Studies show we can eat up to 18 ounces a week of red meat without raising cancer risk. Research on processed meat shows cancer risk starts to increase with any portion.
When meat is preserved by smoking, curing or salting, or by the addition of preservatives, cancer-causing substances (carcinogens) can be formed. These substances can damage cells in the body, leading to the development of cancer.
6. If consumed at all, limit alcoholic drinks to 2 for men and 1 for women a day.
For cancer prevention, AICR recommends not to drink alcohol. However, our expert report recognizes that modest amounts of alcohol may have a protective effect on coronary heart disease. If you do drink alcohol, limit your consumption to no more than two drinks a day for men and one drink a day for women.
The evidence that all types of alcoholic drinks increase the risk of a number of cancers is now stronger than it was in the mid-1990s. There is convincing evidence that alcohol increases the risk of cancer of the mouth, pharynx, larynx, esophagus and breast, as well as colorectal cancer in men.
Alcoholic drinks also probably increase the risk of colorectal cancer in women as well as liver cancer.
Scientists are still researching how alcohol causes cancer. One theory is that alcohol can directly damage our DNA, increasing our risk of cancer. Research shows that alcohol is particularly harmful when combined with smoking.
7. Limit consumption of salty foods and foods processed with salt (sodium).
Consuming too much salt can be harmful to our health, increasing our risk of stomach cancer as well as high blood pressure.
Our daily intake of salt should be less than 2,400 milligrams. We actually need much less than this. Most people in the United States currently consume more than 2,400 mg, but there are simple ways to cut down on our intake.
The expert panel found that salt and salt-preserved foods probably increase the chance of developing stomach cancer. Studies have shown that high salt intake can damage the lining of the stomach. This is one way in which it might increase the risk of stomach cancer.
Most of the salt in our diets comes from processed foods. We are not always aware that these foods are high in salt because they may not taste “salty,” so make sure to read the sodium content on the Nutrition Facts label. Watch out for breakfast cereals, bread, frozen meals, pizza and chips. Also, check the amount of sodium in canned products, such as soups and sauces, and avoid processed meats. Even sweet foods like cookies can contain high levels of salt.
8. Don’t use supplements to protect against cancer.
To reduce your risk of cancer, choose a balanced diet with a variety of foods rather than taking supplements.
The expert report found strong evidence that high-dose supplements of some nutrients can affect the risk of different cancers. The panel judged that in general, the best source of nourishment is food and drink, not dietary supplements. Nutrient-rich whole foods contain substances that are necessary for good health–like fiber, vitamins, minerals and phytochemicals. (The plant-based foods are the source of many cancer-fighting compounds. Be sure to fill your plate two-thirds (or more) with a variety of vegetables, fruits, whole grains and beans, and one-third (or less) of animal protein.)
Some studies have shown that supplements can upset the balance of nutrients in the body. More research needs to be done, but this is one way that they might affect our risk of cancer.
There are some situations when supplements are recommended. These are the most common situations when taking a supplement can be beneficial:
All women of childbearing age intending to conceive a child should take a folic acid supplement before conception and up to the twelfth week of pregnancy.
Pregnant women and nursing mothers should also take a vitamin D supplement and possibly an iron supplement if their iron levels are low.
Children between six months and five years could benefit from taking drops containing vitamins A, C and D, although children with a good appetite who eat a wide variety of foods may not need them.
Frail older people who have low calorie needs may benefit from a low-dose, balanced multi-vitamin.
Older people should consider taking a vitamin D supplement, as should: people who rarely go outdoors, people who cover up all their skin when outdoors, those who don’t eat meat or oily fish.
If you want more advice on any of these situations, it’s best to contact your doctor or a registered dietitian.
9. It is best for mothers to breastfeed exclusively for up to 6 months and then add other liquids and foods.
Evidence shows that breastfeeding can help protect mothers from breast cancer. It also protects babies from excess weight gain that can lead to their being overweight in adult life. And overweight adults have higher cancer risk.
According to the expert report, the evidence that breastfeeding protects mothers against breast cancer is convincing. Having been breastfed probably protects children against overweight and obesity. Overweight and obese children tend to remain overweight in adult life.
Breastfeeding lowers the levels of some cancer-related hormones in the mother’s body, reducing the risk of breast cancer. At the end of breastfeeding, the body gets rid of any cells in the breast that may have DNA damage. This reduces the risk of breast cancer developing in the future.
Research shows that babies who are breastfed are less likely to consume too many calories and too much protein than babies who are fed infant formula. This means that they are less likely to become overweight or obese as they grow up.
If you’re planning to breastfeed your baby, your doctor or certified lactation consultant will be able to provide more information and support.
10. After treatment, cancer survivors should follow the recommendations for cancer prevention.
Anyone who has received a diagnosis of cancer should receive specialized nutritional advice from an appropriately trained professional. Once treatment has been completed, if you are able to do so (and unless otherwise advised), aim to follow our cancer prevention recommendations for diet, physical activity and healthy weight maintenance.
Cancer survivors are people who are living with a diagnosis of cancer, including those who have recovered from the disease.
There is growing evidence that physical activity and other measures that help us to maintain a healthy weight, such as a balanced diet, may help to prevent cancer recurrence, particularly for breast cancer. However, the evidence is not yet clear enough to be able to make any specific recommendations for cancer survivors in general, or for those who are survivors of any specific form of cancer.
These recommendations can also reduce the risk of other chronic diseases like heart disease and diabetes.