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Cancer Risk and Prevention

Controlling Portion Sizes

It's no secret, getting to a healthy weight is as simple as balancing the calories you eat with the calories you burn. When that doesn’t happen, you gain weight. Everything you eat has calories, and everything you do uses calories. For example, if you weigh150 pounds and are active, you need about 2,250 calories per day to maintain this weight, versus about 1,950 calories if you are sedentary.

It helps to know that 1 pound of body fat equals 3,500 calories. That means that to lose 1 pound per week, you need to create a “deficit” of 500 calories per day. You can do this, for example, by eating 250 fewer calories a day, and burning an extra 250 calories through physical activity (such as by walking 2½ miles).

As meals “super-size,” so do American waistlines

It seems like everything these days is “super-sized.” Cutting back on calories can be as simple as watching your portion sizes, especially of foods and beverages that are high in fat or sugar.

Eating smaller portions of food is one of the easiest ways to cut back on calories – but it can also be one of the most challenging, with the current trend of super-sizing. Huge portions, all-you-can-eat-buffets, and extra-large “single servings” of chips, candy bars, and other snack foods can all lead to overeating.

How do you know a reasonable portion of food when you see it? Visualize the objects mentioned below when eating out, planning a meal, or grabbing a snack. For example, for people who eat meat, the amount recommended as part of a healthy meal is 3 to 4 ounces – it will look about the same size as a deck of cards.

What a normal portion size looks like

  • 1 oz. meat = size of a matchbox
  • 3 oz. meat = size of a deck of cards or bar of soap (the recommended portion for a meal)
  • 8 oz. meat = size of a thin paperback book
  • 1 medium potato = size of a computer mouse

Even some bagels have become super-sized, which gives this reasonably healthy breakfast item a high calorie count. Bakeries and grocery stores often carry jumbo bagels that measure 4¼ inches across and contain 300 to 400 calories each. A regular, 3-inch-diameter bagel has about 150 calories.

To eat smaller portions, try the following ideas

When eating out

  • Look for plant-based entrees on the menu, like a veggie plate or a salad with lean protein, like chicken, tofu, or fish on top.
  • If you're trying to eat healthy and watch your weight but find yourself at a fast food restaurant, consider salads, smaller sandwich options, or grilled chicken options.
  • Say 'no' to super-sizing. Instead, order the smallest size available. Drink water or unsweetened iced tea instead of soda.
  • Share an entrée with a friend when you go to a restaurant.
  • Ask for half your meal to be packed for you and eat it for lunch the next day.

At home

  • Don’t “eat from the bag.” When snacking, place a few chips, crackers, or cookies in a bowl to help keep from overeating.
  • Buy single portions of snack foods so you’re not tempted by the whole bag or box.
  • Like butter and sour cream on your baked potato? Mayonnaise and cheese on your sandwich? Cream cheese on your bagel? Use half the amount you usually do – and save even more calories by using low-fat varieties.

Boost servings of fruits and vegetables

The American Cancer Society (ACS) recommends eating a colorful variety of fruits and vegetables each day to help prevent cancer. Substitute low calorie, high-fiber fruits and vegetables for higher calorie foods and snacks – it will help you get the fruits and vegetables you need, feel full, and save on calories!

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.

Last Revised: October 18, 2021

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