Specific dynamic action

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Specific dynamic action (SDA), also called the thermic effect of food (TEF) or dietary-induced thermogenesis (DIT), is the extra energy your body uses to digest, absorb, and process the nutrients from the foods you eat. Brown fat adds a small amount of heat after meals, but SDA is mainly about the energy cost of processing food. It is one part of daily energy use, along with resting metabolism and the energy used during activity.

Typically about 10% of the calories you eat go toward TEF, but this varies by the type of nutrient. Protein is the most energy-intensive to process, carbohydrates fall in the middle, and fats are the easiest to process and cause the least TEF.

SDA can be modestly increased by vigorous or long-duration aerobic exercise and by weight training, and caffeine at meals can raise TEF a little. Overall, these effects are small—usually only a few extra calories per hour.

What mainly determines TEF is the total calories you eat and the mix of macronutrients. How often you eat doesn’t have a strong effect on TEF if your daily calories stay the same.

Some studies suggest TEF may be lower in people with obesity or insulin resistance, but findings are mixed. A lower TEF could contribute to weight gain, but obesity and insulin resistance themselves may also influence TEF in complex ways.

The mechanism isn’t fully understood, but TEF is highest for protein because processing protein costs more energy. There’s no solid evidence that foods like celery or grapefruit have negative calories; TEF depends on the overall nutrient mix and a person’s insulin sensitivity.

Some research indicates adding chili peppers and medium-chain triglycerides (MCTs) to meals can boost TEF, potentially aiding weight control, but results vary.

TEF is typically measured over several hours after a meal, with many studies looking at five to six hours or more.

In short: TEF is the energy cost of processing food, varies by nutrient type, is only modestly influenced by exercise and caffeine, and relates to obesity and insulin resistance in complex ways. The total amount and composition of calories in a meal are the main drivers.