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Cancer Risk and Prevention

Diet and Physical Activity: What’s the Cancer Connection?

How much do daily habits like diet and exercise affect your risk for cancer? More than you might think. Research has shown that poor diet and not being active are key factors that can increase a person’s cancer risk. The good news is that you can do something about this.

Besides quitting smoking, some of the most important things you can do to help reduce your cancer risk are:

  • Get to and stay at a healthy weight throughout life.
  • Be physically active on a regular basis.
  • Follow a healthy eating pattern at all ages.
  • Avoid or limit alcohol.

The evidence for this is strong. The World Cancer Research Fund estimates that at least 18% of all cancers diagnosed in the US are related to body fatness, physical inactivity, alcohol consumption, and/or poor nutrition, and thus could be prevented.

Control your weight

Getting to and staying at a healthy weight is important to reduce the risk of cancer and other chronic diseases, such as heart disease and diabetes. Being overweight or obese increases the risk of several cancers, including those of the breast (in women past menopause), colon and rectum, endometrium (the lining of the uterus), esophagus, pancreas, liver, and kidney, as well as several others.

Being overweight can increase cancer risk in many ways. One of the main ways is that excess weight causes the body to make and circulate more estrogen and insulin, hormones that can stimulate cancer growth.

What’s a healthy weight?

One of the best ways to get an idea if you are at a healthy weight is to check your body mass index (BMI), a score based on the relationship between your height and weight. Use our easy online BMI calculator to find out your score.

Most people are at a normal weight if their BMI is below 25. Ask your doctor what your BMI number means and what action (if any) you should take.

If you are trying to control your weight, a good first step is to watch portion sizes, especially of foods high in calories, fat, and added sugars. Also try to limit your intake of high-calorie foods and drinks. Try writing down what and how much you eat and drink for a week, then see where you can cut down on portion sizes, cut back on some not-so-healthy foods and drinks, or both!

For those who are overweight or obese, losing even a small amount of weight has health benefits and is a good place to start.

Move more and sit less

Watching how much you eat will help you control your weight. The other key is to be more physically active. Being active can help reduce your cancer risk by helping with weight control. It can also help improve your hormone levels and the way your immune system works.

More good news – physical activity helps you reduce your risk of heart disease and diabetes, too! So grab your athletic shoes and head out the door!

The latest recommendations for adults call for 150-300 minutes of moderate intensity or 75-150 minutes of vigorous intensity activity each week, or a combination of these. Getting to or exceeding the upper limit of 300 minutes is ideal. For kids, the recommendation is at least 60 minutes of moderate or vigorous intensity activity each day.

  • Moderate activities are those that make you breathe as hard as you would during a brisk walk. This includes things like walking, biking, or even housework and gardening.
  • Vigorous activities make you use large muscle groups and make your heart beat faster, make you breathe faster and deeper, and also make you sweat.

It’s also important to limit sedentary behavior such as sitting, lying down, watching TV, or looking at your phone or computer.

Being more physically active than usual, no matter what your level of activity, can have many health benefits.

Follow a healthy eating pattern

Eating well is an important part of improving your health and reducing your cancer risk. Take a good hard look at what you typically eat each day, and try to build a healthy diet plan for yourself and your family.

A healthy eating pattern includes… 

  • Foods high in vitamins, minerals, and other nutrients
  • Foods that are not high in calories, and that help you get to and stay at a healthy body weight
  • A colorful variety of vegetables – dark green, red, and orange
  • Fiber-rich beans and peas
  • A colorful variety of fruits 
  • Whole grains (in bread, pasta, etc.) and brown rice

A healthy eating pattern limits or does not include… 

  • Red meats like beef, pork, and lamb
  • Processed meats like bacon, sausage, luncheon meats, and hot dogs
  • Sugar-sweetened beverages, including soft drinks, sports drinks, and fruit drinks
  • Highly processed foods and refined grain products

Tips for a healthy eating pattern

  • Fill most of your plate with colorful vegetables and fruits, beans, and whole grains.
  • Choose fish, poultry, or beans as your main sources of protein instead of red meat or processed meats.
  • If you eat red or processed meats, eat smaller portions.

More healthy eating tips

  • Prepare meat, poultry, and fish by baking, broiling, or poaching rather than by frying or charbroiling.
  • Follow a healthy eating pattern when you eat away from home. Eat vegetables, whole fruit, and other low‐calorie foods instead of high‐calorie foods such as French fries, potato and other chips, ice cream, doughnuts, and other sweets. Restaurants often serve large portions, but you don’t have to eat it all in one sitting. Ask for a to-go box from the start, and pack up your leftovers for lunch or dinner the next day.  
  • Don't supersize your plate—and yourself! If you enjoy some high‐calorie foods once in a while, eat smaller portions. 
  • Be a savvy consumer. Pay attention to food labels in the grocery store and on restaurant menus.
  • Limit your use of creamy sauces, dressings, and dips with vegetables and fruits.

It is best not to drink alcohol.

Alcohol increases the risk for several types of cancer. The more alcohol you drink, the higher your cancer risk. But for some types of cancer, most notably breast cancer, consuming even small amounts of alcohol can increase risk.

People who choose to drink alcohol should limit their intake to no more than 2 drinks per day for men and 1 drink per day for women. The recommended limit is lower for women because of their smaller body size and slower breakdown of alcohol.

A drink of alcohol is defined as 12 ounces of beer, 5 ounces of wine, or 1½ ounces of 80-proof distilled spirits (hard liquor). In terms of cancer risk, it is the amount of alcohol, not the type of alcoholic drink that is important.

Reducing cancer risk in our communities

Adopting a healthier lifestyle is easier for people who live, work, play, or go to school in an environment that supports healthy behaviors. Working together, communities can create the type of environment where healthy choices are easy to make.

We all can be part of these changes. Let’s ask for healthier food choices at our workplaces and schools. For every junk food item in the vending machine, ask for a healthy option, too. Support restaurants that help you to eat well by offering options like smaller portions, lower-calorie items, and whole-grain products. And let’s help make our communities safer and more appealing places to walk, bike, and be active.

The bottom line

Let’s challenge ourselves to lose some extra pounds, increase our physical activity, make healthy food choices, avoid or limit alcohol, and look for ways to make our communities healthier places to live, work, and play.

To learn more, see the American Cancer Society Guideline for Diet and Physical Activity for Cancer Prevention.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

Rock CL, Thomson C, Gansler T, et al. American Cancer Society guideline for diet and physical activity for cancer prevention. CA Cancer J Clin. 2020;70(4). doi:10.3322/caac.21591. Accessed at on June 9, 2020.

World Cancer Research Fund/American Institute for Cancer Research. Diet, Nutrition, Physical Activity, and Cancer: A Global Perspective. Continuous Update Project Expert Report 2018. Accessed at on June 2, 2020.

Last Revised: June 9, 2020

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