Keys to a Healthy Diet

What we eat is directly and intricately linked to our health. Not only can eating right help prevent many of the most burdensome diseases in America today, such as heart disease and diabetes, but it can also help prevent several types of cancer.

Diet, along with physical activity and body weight, are key components of cancer prevention: Together these factors can help prevent approximately one-third of cancers in the U.S.1 and they are all things over which we have some personal control.

Eating right and maintaining a healthy weight can make cancer much less likely – and that is good news. EWG’s Cancer Defense Diet has some tips:

See the types of food that can help reduce cancer risk.

Healthy Foods

The evidence is clear: Eating a variety of fruits, vegetables and other plant-based foods is essential to building a cancer-fighting diet.

Mediterranean diets, and other diets high in fruits, vegetables, whole grains, nuts and legumes, are linked to a decreased risk of developing a long list of cancers. This includes colorectal, liver, lung, pancreas, and head and neck cancers.2,3,4,5

On the flip side, Western diets that are high in red and processed meats have been associated with increased risks of lung, colorectal, gastric and other digestive system cancers.3,5,6,7

While there are specific things you can do – from utilizing different cooking methods to pairing certain foods together – to enhance the cancer-fighting benefits of certain foods, following the Department of Agriculture’s Dietary Guidelines for Americans (1 1/2 to 2 cups of fruit and 2 1/2 to 3 cups of vegetables daily) is a great place to start.

Eating fruits and vegetables might have less of a positive impact if you’re eating a lot of red and processed meats, too. Substituting a portion of red meat with white meat or fish has been found to decrease cancer risks.8 We have tips on other ways to get your protein in a healthy way.

Also, drink alcohol in moderation – at most – and you’ll be well on your way to a diet that has been shown to reduce cancer risks.9,10,11

To see how your diet stacks up and get suggestions on how to add variety of nutrients and maximize their benefits, try our Nutrition Calculator for Cancer Prevention.

Why eat a variety of plant-based foods?

While there is strong evidence our diets can play an important role in cancer prevention, the results of research on individual foods and nutrients have been less consistent.12

It’s important to remember, no food or nutrient will either cause or prevent all cancers. Instead, we need to weigh the entirety of evidence.

Foods are complex and we don’t eat nutrients in isolation, so focusing on individual foods or nutrients may not be the best approach. More likely, health benefits arise from the interactions and synergies of the foods we eat and the nutrients they contain. Don’t be fooled into thinking a single food or nutrient is a panacea.

How can food reduce cancer risks? Learn about the hallmarks of cancer.

Fruits, vegetables and other plant-based foods contain many different nutrients, phytochemicals and other compounds that may make cancer less likely to develop. There are a variety of impacts the food you eat can have. For example, fiber can clear harmful chemicals from our bowels, vitamin C acts as an antioxidant and calcium may help prevent some cellular damage.

But there are also nutrients and food compounds that may ward off cancer by fighting against the development of the hallmarks of cancer. The hallmarks of cancer are the processes, mechanisms and characteristics that make cancer cells different from normal cells.13,14 They define how cancer cells go rogue and no longer listen to our body’s commands to grow and divide, instead forming tumors and invading other parts of our body. You can learn more about them here.

Halifax Project researchers, organized by the nonprofit Getting to Know Cancer, investigated how the concept of cancer hallmarks can be used to create effective, low-toxicity cancer treatments.15 These treatments are showing great promise in laboratory studies.

Previously, this group hypothesized that exposures to multiple chemicals which impact the hallmarks of cancer could produce a mixture that may cause or promote cancer development. But just as some chemicals can negatively affect processes in ways that make cancer development more likely, others can block or defend against those same processes and make cancer less likely to develop.

Learn which foods can help prevent the initiation of cancer hallmarks in cells

Finding healthy foods

Foods and the different compounds they contain may prove to be important cancer prevention tools when viewed through the hallmarks of cancer framework.

A healthy diet is a well-balanced, varied diet. A specific nutrient on its own may offer little-to-no protection against cancer, but synergies between nutrients likely amplify beneficial effects.

See some of the nutrients, phytochemicals and other compounds that can help prevent the initiation of cancer hallmarks, as well as in which foods they’re found and the evidence of cancer prevention, below.

Carotenoids including lycopene and beta-carotene
B vitamins
Vitamin D
Eicosapentanoic acid (EPA)
Oleanolic acid
Lentinus edodes (lentinan)
gamma-Linolenic acid (GLA)
Carotenoids including lycopene and beta-carotene


Colorful fruits and vegetables: tomatoes (especially cooked), leafy greens, carrots, watermelon, papaya, grapefruit, peppers, guava, asparagus, purple cabbage, squash, green peas, broccoli, Brussels sprouts


Several studies suggest some carotenoids can protect against lung cancer and possibly breast and prostate cancers. However, dietary supplements of these and other antioxidants should be avoided because high doses can have the opposite effect and increase lung cancer risk in smokers.
Good evidence
Good evidence
Some evidence
Evidence in animal or lab studies
Controversial evidence

Choose foods, not nutritional supplements

Our bodies have evolved to operate under a narrow range of conditions. Both deficiencies and excesses of hormones, vitamins, minerals and other nutrients can have serious health consequences.

Think of a high performance engine – altering the octane level of the gas you use or pouring in more oil not only wouldn’t improve performance, it could cause a breakdown.

Take beta-carotene, for example. There are famous investigations that show that, at levels you’d get from dietary intakes, beta-carotene has been linked to decreased lung cancer risk. But, intervention studies found that high dose beta-carotene supplements actually promote lung cancer development among smokers.16,17

High dose supplements of antioxidants or folate, for example, can also interfere with certain cancer therapies. For these reasons, we recommend caution in the use of nutritional supplements unless you have a specific deficiency or medical concern. 

Don’t overeat

One of the most important roles of a proper diet is to help maintain a healthy body weight. Obesity and excess body fat raise hormone levels and promote inflammation, which can help feed and promote tumor growth. Check out the chart below to find out what portions are appropriate for your age and activity level.


1World Cancer Research Fund/American Institute for Cancer Research. Food, Nutrition, Physical Activity, and the Prevention of Cancer: A Global Perspective. 2007.

2Lukas Schwingshackl and Georg Hoffmann, Adherence to Mediterranean Diet and Risk of Cancer: An Updated Systematic Review and Meta-Analysis of Observational Studies. Cancer Medicine, 2015; 4(12):1933-1947.

3Paola Bertuccio et al., Dietary Patterns and Gastric Cancer Risk: A Systematic Review and Meta-Analysis. Annals of Oncology, 2013; 24(6):1450-1458.

4Wen-Qing Li et al., Index-Based Dietary Patterns and Risk of Head and Neck Cancer in a Large Prospective Study. American Journal of Clinical Nutrition, 2014; 99(3):559-566.

5Huakang Tu et al., Different Dietary Patterns and Reduction of Lung Cancer Risk: A Large Case-Control Study in the U.S. Scientific Reports, 2016; 6:26760.

6Zaynah Abid et al., Meat, Dairy, and Cancer. American Journal of Clinical Nutrition, 2014; 100 Suppl 1:386S-393S.

7Veronique Bouvard et al., Carcinogenicity of Consumption of Red and Processed Meat. Lancet Oncology, 2015; 16(16):1599-1600.

8Carrie R. Daniel et al., Prospective Investigation of Poultry and Fish Intake in Relation to Cancer Risk. Cancer Prevention Research, 2011; 4(11):1903-1911.

9James R. Cerhan et al., Adherence to the AICR Cancer Prevention Recommendations and Subsequent Morbidity and Mortality in the Iowa Women’s Health Study Cohort. Cancer Epidemiology, Biomarkers & Prevention, 2004; 13(7):1114-1120.

10Lukas Schwingshackl and Georg Hoffmann, Diet Quality as Assessed by the Healthy Eating Index, the Alternate Healthy Eating Index, the Dietary Approaches to Stop Hypertension Score, and Health Outcomes: A Systematic Review and Meta-Analysis of Cohort Studies. Journal of the Academy of Nutrition and Dietetics, 2015; 115(5):780-800.

11Sarah J.O. Nomura et al., WCRF/AICR Recommendation Adherence and Breast Cancer Incidence Among Postmenopausal Women With and Without Non-Modifiable Risk Factors. International Journal of Cancer, 2016; 138(11):2602-2615.

12Jonathan D. Schoenfeld and John P.A. Ioannidis, Is Everything We Eat Associated With Cancer? A Systematic Cookbook Review. American Journal of Clinical Nutrition, 2013; 97(1):127-134.

13Douglas Hanahan and Robert A. Weinberg, The Hallmarks of Cancer. Cell, 2000; 100(1):57-70.

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