A 1999 Mayo Clinic study carefully assessed the number of calories a group of 16 subjects needed to maintain their weight (also known as their Basal Metabolic Rate or BMR). Then they were each given an extra 1000 calories per day for 8 weeks and not allowed to do any extra exercise. While fat gain occurred, it varied widely, from less than a pound to more than 9 pounds. What was the secret that allowed some of the subjects to gain almost no weight while others gained more than a pound a week?
Dr. James Levine, the researcher behind the study, came up with an answer which he dubbed Non-Exercise Activity Thermogenesis, or NEAT.
Thermogenesis is the process of heat production in organisms, particularly warm-blooded animals like humans. In order to generate heat, the body must expend energy, so thermogenesis is associated with burning calories. (Perhaps not coincidentally, a calorie is a unit of energy; specifically, the energy needed to raise the temperature of 1 gram of water by 1° C. When referring to diet, a "calorie" is actually a "kilocalorie" or the energy needed to raise 1 kilogram of water by 1° C. Isn't that fascinating?)
There are three main drivers of thermogenesis in the body:
Basal Metabolism, usually defined by the Basal Metabolic Rate (BMR), is the energy expended by the body while at rest to sustain vital functions. For most people, this is the biggest expenditure of energy. (You can find BMR calculators online, like this one.)
Physical Activity is the next biggest factor. It varies widely depending on a person's activity level, including simple actions such as standing or typing and demanding actions such as lifting or running.
The Thermic Effect of Food (TEF) is the energy expended digesting and processing food. Different foods require different amounts of energy to process. Protein requires more energy than fats or carbohydrates, while simple carbohydrates require the least amount. For most people, this will only be about 100-200 calories per day.
Of the study, Dr. Levine wrote:
Physical activity thermogenesis can be subdivided into volitional exercise (sports and fitness-related activities) thermogenesis and what we characterize as nonexercise activity thermogenesis (NEAT). NEAT is the thermogenesis that accompanies physical activities other than volitional exercise, such as the activities of daily living, fidgeting, spontaneous muscle contraction, and maintaining posture when not recumbent.
So even though the study subjects were prohibited from exercising, some participants unconsciously increased their activity levels anyway, through NEAT, burning off some or all of the added calories.
Now, how can you use NEAT to help you burn extra calories?
Stand rather than sit. Walk rather than stand. Move rather than remain still. Take the stairs instead of the escalator. Park farther from the entrance so you walk the extra distance. Stand while talking on the phone. Sit on the floor while watching TV. (You will find yourself adjusting your position frequently.)
As the study noted, even small movements like fidgeting have a cumulative effect. But few options beat walking. Work as much of it into your daily routine as you can.
Remember: if you want to burn extra calories, NEAT is neat. Yeah, that's right: I went there.
Be seeing you.
-gary