Overview
Some of the calories in the food you eat are used to digest, absorb, metabolize, and store the remaining food, and some are burned off as heat. This process is known under various names, notably diet-induced thermogenesis (DIT), specific dynamic action (SDA), and the thermic effect of food (TEF).[1][2]
The TEF represents about 10% of the caloric intake of healthy adults who eat a standard mixed-macronutrient diet,[3] but your actual number will depend on several factors, including your age and the meal timing, and macronutrient composition — carbs, fat, and protein — of your meal. The energy required to digest each macronutrient (its TEF) can be expressed as a percentage of the energy provided by the macronutrient:[4][5]
- Fat provides 9 calories per gram, and its TEF is 0–3%.
- Carbohydrate provides 4 calories per gram, and its TEF is 5–10%.
- Protein provides 4 calories per gram, and its TEF is 20–30%.
Resting metabolic rate (RMR) refers to the amount of energy used while the body is at rest. To put it another way, it’s how many calories your body would use if you were lying down all day. The TEF is related to this measure, as it refers to the increase in RMR after the consumption of food and accounts for about 10% of daily energy expenditure, as we noted above.
How is the TEF assessed?
There are several methods used for measuring the TEF, as seen in the table below. All come with varying degrees of complexity, cost, accuracy, and reliability. These measurements must be done in a laboratory or clinical setting with specialized equipment and trained technicians.
| METHOD | COMPLEXITY | COST | MEASUREMENT TIME[BR](in hours) |
|---|---|---|---|
| Confinement system | High | Moderate/high | 1–48 |
| Metabolic chamber | High | Moderate/high | 2–48 |
| Respiratory chamber | High | Moderate/high | 1–100 |
| Ventilated hood/canopy | Moderate | Low/moderate | 0.2–6 |
| Isotope dilution | Low | High | 48–240 |
Adapted from Calcagno et al. J Am Coll Nutr. 2019.[6]
Examine Database: Thermic effect of food (TEF)
| Intervention | Grade | Effect | Detail |
|---|---|---|---|
| Vegan Diet | B | ||
| Ginger | C | ||
| Psyllium | D | ||
| Green Tea Extract | |||
| Medium-chain Triglycerides |
References
Examine Database References
- Psyllium - Khossousi A, Binns CW, Dhaliwal SS, Pal SThe acute effects of psyllium on postprandial lipaemia and thermogenesis in overweight and obese menBr J Nutr.(2008 May)
- Ginger - Muhammad S Mansour, Yu-Ming Ni, Amy L Roberts, Michael Kelleman, Arindam Roychoudhury, Marie-Pierre St-OngeGinger consumption enhances the thermic effect of food and promotes feelings of satiety without affecting metabolic and hormonal parameters in overweight men: a pilot studyMetabolism.(2012 Oct)
- Vegan Diet - Neal D Barnard, Anthony R Scialli, Gabrielle Turner-McGrievy, Amy J Lanou, Jolie GlassThe effects of a low-fat, plant-based dietary intervention on body weight, metabolism, and insulin sensitivityAm J Med.(2005 Sep)
- Vegan Diet - Hana Kahleova, Kitt Falk Petersen, Gerald I Shulman, Jihad Alwarith, Emilie Rembert, Andrea Tura, Martin Hill, Richard Holubkov, Neal D BarnardEffect of a Low-Fat Vegan Diet on Body Weight, Insulin Sensitivity, Postprandial Metabolism, and Intramyocellular and Hepatocellular Lipid Levels in Overweight Adults: A Randomized Clinical TrialJAMA Netw Open.(2020 Nov 2)
- Green Tea Extract - Thielecke F, Rahn G, Böhnke J, Adams F, Birkenfeld AL, Jordan J, Boschmann MEpigallocatechin-3-gallate and postprandial fat oxidation in overweight/obese male volunteers: a pilot studyEur J Clin Nutr.(2010 Jul)
- Medium-chain Triglycerides - A A Papamandjaris, M D White, P J JonesComponents of total energy expenditure in healthy young women are not affected after 14 days of feeding with medium-versus long-chain triglyceridesObes Res.(1999 May)