Specific Dynamic Activity

The Specific Dynamic Activity (SDA) represents the caloric energy required for the processes of digestion and reflexive brown fat thermogenesis after eating. Thermogenesis is a term referring to heat production by the body.

Our body is actually a "heat factory" with about 75% of the caloric energy that we consume as food going into heat production. About a quarter of what's left goes into energy production for muscular movement, thinking, and all other bodily processes—except for the 6 to 10% that consumed by the SDA. A certain amount of energy usually—expressed as a percentage of overall body energy—is consumed by digestion and brown fat metabolism automatically.

After eating, that "warm feeling" you experience is a reflexive response to the increased calorie consumption of brown adipose tissue which gives off extra heat for better digestion. This brown adipose tissue is a primary thermoregulator (i.e., a heat regulator) of the body, and is specifically designed to create heat to stabilize body temperatures. (By the way, white (or yellow) adipose is designed strictly for fat storage and body part insulation.) There are many thermogenic supplements designed to stimulate brown fat metabolism to increase calorie usage by the body. MaHuang is one of those herbal supplements used for this purpose—but is it right for you? Only typing will tell!

So far, we've been able to compute your SDA as a fixed 6% of your BMR and DPAN combined.

Next, we add all three figures together:

BMR 1,500 calories (Laying in bed all day.)

DPAN. + 600 calories (Exercise, job, lifestyle.) SDA + 126 calories (6% of 2,100) (Digestion)

TCND 2,226 calories

This adds up to 2,226 calories, which equals your Total Calorie Need Per Day (TCND). Your body requires this amount to maintain itself at its constant weight, based on all your lifestyle factors.