If you’re watching your weight, you’ve probably heard the phrase “calories in, calories out.” But what does that mean?
A calorie is a unit of energy. The relationship between the calories you take in through food and drinks, and the calories you burn through physical activity and basic functions (like breathing and digestion) is your energy balance.
“If you alter one side of the equation or the other, your body weight will change accordingly,” says Erma Levy, research dietitian in MD Anderson’s Department of Behavioral Science. “Simply put, calories in equals calories out.”
Energy balance is important. When you consume too much energy and burn too little, your body stores that excess energy as body fat. And being overweight increases your risk for several cancers, including colon, pancreatic, endometrial and post-menopausal breast cancer.
Food and energy balance
If you are trying to achieve energy balance, first look at the energy density of the foods you eat.
Energy density is the number of calories in a specific amount of food. Examples of energy-dense foods include cakes, cookies, pies and fried foods. These foods have a lot of calories and not many nutrients.
To lose weight, your best bet is eating low-energy dense foods like fruits and vegetables, whole grains and plant-based sources of protein, like beans. Additional sources of protein include fish, chicken and low-free dairy products.
“Eating low-energy density foods lets you feel full on fewer calories and more nutrients. This can help you lose weight and control your hunger,” Levy says.
She advises following the American Institute for Cancer Research guidelines. Fill at least two-thirds of your plate with plant-based foods, and no more than one-third of you plate with animal protein.
Exercise and energy balance
So, you’ve indulged in some high calorie foods. Can you even the score with a jog around the block? Levy says you need to compare calories burned with those consumed.
“It is fairly common to overestimate calorie burn from exercise,” she says. “For a person who weighs 150 pounds, a 20 minute jog will burn about 190 calories, but a piece of chocolate cake might be 300 calories or more. The key word here is ‘balance.’"
For long-term success, focus on consuming a healthy diet and getting regular physical activity consistently. Make sure your exercise routine includes strength training. This will help you build and maintain muscle, especially as you age.
Muscle mass naturally decreases over time. As a result, the number of calories you burn when you aren’t active declines as well.
“Our bodies’ energy needs slowly decrease as we lose muscle mass, so we cannot eat the same amount as we used to without gaining weight,” says Levy.
If balancing your calorie intake is challenging, an activity tracker or app may help. But, no matter your weight, it’s important to remember that staying physically active and eating well can both reduce your risk for cancer.
Request an appointment at MD Anderson's Lyda Hill Cancer Prevention Center online or call 877-632-6789.