By Roberta H. Anding, MS, Baylor College of Medicine and Texas Children’s Hospital
Edited by Kate Findley and proofread by Angela Shoemaker, Wondrium Daily
You’re probably familiar with the principle “calories in, calories out.” While this is a sound concept, Professor Anding reveals some lesser-known strategies for weight management that don’t involve grueling workouts or fad diets.
Thermic Effect of Food
Your total energy expenditure is determined by your basal metabolic rate (BMR), or calories burned at rest, and physical activity. However, other factors also play a role in burning calories. These include the thermic effect of food—the calories it takes to digest your food—and non-exercise activity thermogenesis (NEAT), which refers to small movements like fidgeting.
While physical activity accounts for 15 percent to 30 percent of your total energy expenditure, the thermic effect of food accounts for between 10 percent and 30 percent. The thermic effect is influenced by the foods you eat.
For example, you burn more calories while digesting protein than carbohydrates. If you eat a meal that’s pure protein, it will give you a thermic effect of food of about 25 percent of the meal’s total calories. Although there are probably few occasions when you’re eating only protein, you can still include more protein in your meals.
Exercise can augment or facilitate this dietary-induced thermogenesis.
“One study showed that if we fed volunteers an additional 1,000 calories, the thermic effect of the food increased the calorie burning by 28 percent,” Professor Anding said. “If they exercised after eating the meal, it increased to 56 percent of the basal metabolic requirement.”
With the exception of obese people, engaging in moderate exercise closely following a meal will enhance that thermic effect of food. If you’ve had a large meal, you might not feel like jogging, but you could take a walk.
Estimating Calories Burned
You can estimate your total energy expenditure, or how many calories you burn each day. This will, in turn, help you determine how many calories you should consume if your goal is weight loss or maintenance.
First, calculate your ideal body weight using the Hamwi equation, which is based on height, frame size, and sex. If you’re a female who is 5 feet 4 inches, you would allow 100 pounds for the first 5 feet of height and 5 pounds for each inch after that. That gives you an ideal body weight of 120 pounds.
Next, you would multiply your ideal body weight times 10, and that will give you the calories you need for your BMR. Since you’re 5 feet 4 inches, 120 pounds, your ideal body weight times 10 gives you 1,200 calories for your BMR. That means that if you’re laying in the bed doing nothing, you’ll need 1,200 calories to support that involuntary activity.
One problem with weight-reduction diets is that the total caloric intake is actually too low. If the person in the given example consumes less than 1,200 calories, she will lose significant amounts of lean mass.
For men, if a man is 5 feet 10 inches, he gets 106 pounds for the first 5 feet of height and 6 pounds for each inch after that. For his BMR, he would need about 1,660 calories.
Now factor into the equation the amount of calories burned through purposeful activity and calories burned through NEAT. For people who are constantly in motion, NEAT may be the hidden factor for preventing weight gain.
A study at the Mayo Clinic indicated that participants gained less weight if they effectively activated NEAT when overfed 1,000 calories per day as compared to those participants who didn’t use NEAT. This difference might also explain why some individuals seem to eat whatever they want and don’t gain weight. Constant motion, fidgeting, or maintaining a better posture are all potential factors for not gaining weight.
If you want to lose weight, find simple ways to incorporate more movement into your day. When you’re talking on the phone, stand. If you’re sitting at a computer all day, set a timer. Get up and move every 10 to 15 minutes.
The calories burned during physical activity vary significantly from a competitive athlete to someone with a desk job, especially when NEAT is factored into the equation.
“In my clinical life, because I work with football players, I have individuals who can eat significant amounts of food and never gain weight,” Professor Anding said.
She once worked with a Rice cross-country athlete and engineering student who was 6 feet 2 inches and 150 pounds. He estimated that he needed 5,500 calories, which he was already eating. Although his calculations were correct, they didn’t match his weight.
Only after increasing his caloric intake to 8,500 calories a day did he actually gain weight. As it turned out, when he studied for engineering, he paced.
He accounted for purposeful exercise in his equation, and he had appropriately estimated his calories burned from BMR, but he didn’t consider the calories burned from NEAT. Although making these calculations and following them can be challenging for people trying to gain weight, it does show how NEAT can be an effective tool for burning calories with minimal effort.
This article was edited by Kate Findley, Writer for Wondrium Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for Wondrium Daily.
Professor Roberta H. Anding is a registered dietitian and Director of Sports Nutrition and a clinical dietitian at Baylor College of Medicine and Texas Children’s Hospital. She also teaches and lectures in the Baylor College of Medicine’s Department of Pediatrics, Section of Adolescent Medicine and Sports Medicine, and in the Department of Kinesiology at Rice University.