So the theory goes that there are foods that provide negative calories, presumably because the calories it takes to digest the foods are greater than the calories in the food. While it is true that digesting food burns calories, it is not true that any food has negative calories.
Thermic Effect of Food
The Thermic Effect of Food (TEF) is the reason for the whole “negative calories” concept. TEF represents the energy expenditure above resting metabolism that contributes to digestion and storage of food. In other words, you put energy in (burn calories) to get energy out (calories available from digested food).
However, the TEF is generally estimated about 10% of all calories consumed. You really don’t calculate it for individual foods. Instead, you estimate it based on all the calories for the day. So a 1,500 calorie day uses 150 calories to digest and store food. Because of their fiber content, veggies have a higher thermic effect at 20% of calories consumed, but it still doesn’t pass 100% so it can’t have negative calories.
The other reason food can’t take credit for “negative calories” is that TEF is included in the calculations that estimate a person’s energy needs – total metabolism. Besides TEF, the other components are resting metabolic rate (RMR – calories burned at rest, lying down, and practically sleeping) and also daily exercise/daily living activities (deliberate exercise or normal activities like house cleaning). So when you’re figuring out the calories you need for weight loss, TEF is already accounted for.
Love Low Calorie, Whole Foods
If you feel bummed like the day you learned Santa wasn’t real, turn that frown upside down. Focus on the fact that vegetables and fruits are naturally low in calories and they have vitamins, minerals, and phytochemicals your body needs to stay healthy. You have to eat 12 large celery stalks to get 100 calories. That’s a LOT of celery to choke down. However, only four Hershey kisses and you’ve reached 100 calories – a much smaller volume.
So piling up on veggies will nourish you and fill you up without taking a chunk out of your daily calorie budget. You’ll also feel more energy and you’ll be happy knowing you are taking good care of yourself! Don’t worry about the small nuances such as TEF. They really don’t matter in the big picture.
October 6th, 2009