Calorie math and weight loss
Eat less calories than you are burning and you will lose weight. Sounds simple right?
Is a calorie a calorie? And what is a calorie anyway?
To put it simply, a calorie is a measurement of energy. To figure out how many calories are in a food a test is done in a lab under highly controlled conditions. It may be no surprise that the human body is not a controlled system in the same way. So, while an apple may technically have 80 calories, different people will get varying amounts of energy from that food. It takes energy to digest food and digestive issues can affect how many of the calories from a food are actually absorbed. The energy used to digest food is called the thermal effect.
Protein has the greatest thermal effect, meaning it takes the body more energy to digest and break down. In a Journal of the American Medical Association study, people who got 25 percent of their calories from protein burned 227 more calories a day than those who only ate 5 percent of their calories from protein. While most people eat significantly more than 5% of their calories from protein this study does show that increasing protein intake can have beneficial effects.
So even though 3 ounces of chicken breast may have 92 calories on paper, up to 35 percent fewer of those calories will actually be absorbed by the body. "...calories from protein have also been shown to have a greater impact on satiety, and hunger is the enemy of weight loss," says New York weight loss expert Samantha Cassetty, M.S., R.D.
Whole grains vs white grains have a similar effect. When eating whole grains more energy is required to break them down, which leads to less calories being available for storage overall.
Nuts also take a lot of energy to digest. The amount of calories you get from them may be up to 30% less than what the label states.
A lot of this goes back to the idea that eating a diet rich in whole grains, fruits, vegetables and a focus on protein will improve health as well as assist in weight loss.
It also means that listening to your body and focusing on eating satisfying nutrient-rich foods may have more of a positive effect on weight loss than counting calories.
Written by Patti Murphy, RDN, CDCES
