Portion sizes and your cancer risk

How you fill your plate may affect your risk for some cancers.

The bigger your portions, the more calories you consume. And excess calories can lead to weight gain and excess body fat, says Erma Levy, a research dietitian in Behavioral Science at MD Anderson.

“Portion sizes have gotten out of control, which may explain why our waistlines are out of control,” says Levy.

Research shows that being overweight or obese can increase your risk for several types of cancer, including endometrial, colorectal and post-menopausal breast cancer. 

But moderating your portion sizes can help you cut back on excess calories and manage your weight.

Portions vs. servings

A serving is a measured amount of food. Standard serving sizes are determined by the United States Department of Agriculture. A portion is the number of servings of a given food that you choose to eat.

For example, the 9-ounce portion of steak you order in a restaurant has three servings of meat. That huge helping of French fries or massive mound of mac ’n cheese also contain multiple servings.

If you follow the same portion protocols at home, you could end up consuming a lot of excess calories.

Levy says the number of servings you should eat depends on your individual calorie needs and weight-related goals. But understanding what a serving looks like is the first step toward portion control.

Portions and proportions

When it comes to your meals, food proportions are just as important as food portions.

For example, your dinner plate may include a protein like beef or chicken, a starchy vegetable like potatoes, and some kind of green or leafy vegetable.

“Those can be the right ingredients, but people often get the proportions wrong,” Levy says

To reduce your cancer risk and safeguard your waistline, she recommends following the American Institute for Cancer Research (AICR) guidelines: Fill at least two-thirds of your plate with plant foods like non-starchy vegetables, whole grains and fruit.

That means if your plate includes animal-based foods like steak and cheese, you should dish up twice as many plant-based foods, Levy says. While you can still consume too many calories if you stick to this 2-to-1 ratio, it’s a good start, she says.

Even if you’re overweight, eating lots of plant foods can lower your risk for some cancers, according to the AICR.  

More smart serving tips

Most people plan their meals around animal protein, Levy says. That means your choice and preparation of beef, chicken, pork or fish is your focus, and vegetable “sides” are an afterthought.

She recommends paying more attention to your vegetable dishes. You also can replace some of the meat on your plate with plant foods high in protein like beans or tofu.

“You can still include meat, but try to cut down your portions and make plant foods your focus,” she says.

Also, pay attention to the quality of the plant foods you choose, and how you dress them up.

A baked potato counts as a plant food. Add sour cream, shredded cheese or bacon bits, and you’re changing your proportion of plant-based foods to animal-based foods, and adding a lot of calories to your plate. A green salad might be a better choice, but drenched in creamy dressing and tossed with cheese, croutons or other add-ons, the calories will add up.

Seek support

If you don’t feel confident about watching your servings and adjusting your portions. Try talking with your health care provider.

“Being mindful of the number of servings on your plate leads to smarter food choices,” Levy says. “Take time to think about and adjust your food portions for better health.”

Request an appointment at MD Anderson's Lyda Hill Cancer Prevention Center online or call 877-632-6789.

View a printable version of our Serving Size Guide.