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# Specific dynamic action (thermic effect of food)

After a meal the body burns extra energy to digest, absorb, process and store the nutrients. Protein costs the most.

Updated 2026-11-01

## Key facts

- Specific dynamic action (SDA) is the rise in heat production above BMR after eating; on a mixed diet it is about 10 % of the energy eaten.
- It is largest for protein (about 20–30 % of its energy), smaller for carbohydrate (about 5–10 %) and smallest for fat (about 0–3 %). Older textbooks quote 30 %, 5 % and 13 %.
- Main causes: the ATP cost of absorbing nutrients and of storing them (glycogen, fat, protein), of making urea from surplus amino acids and of gluconeogenesis.
- It starts within an hour of eating and can last several hours (about 4–6 hours after a large meal).
- This is why BMR is measured fasting and why about 10 % is added when estimating daily energy needs.

## In detail

- 1. Absorption: active transport in the gut (for example the Na⁺-glucose cotransporter, kept running by Na⁺/K⁺-ATPase) uses ATP.
- 2. Protein: surplus amino acids are deaminated; making one urea costs four high-energy phosphate bonds, and turning the carbon skeletons into glucose or fat costs more ATP.
- 3. Carbohydrate: storing glucose as glycogen costs a few per cent of its energy; turning it into fat (lipogenesis) costs much more.
- 4. Fat: dietary triglyceride is re-esterified and stored almost unchanged, so the cost is small.
- 5. Part of the heat is 'facultative' thermogenesis, driven by the sympathetic system, including brown fat (UCP1) in some people.
- 6. SDA does not add usable energy: it is energy lost as heat, so the net energy a food provides is a little lower than its fuel value.

**Also called**
Diet-induced thermogenesis, Thermic effect of food

## Clinical notes

- High-protein meals increase satiety and heat production, one reason they are used in weight-loss diets.
- In feeding plans for hospital patients, the thermic effect is part of the usual allowance of about 10 % above resting expenditure.
- When BMR is measured, a recent meal (especially one rich in protein) falsely raises the value.

## Pathways

- [Urea cycle](https://durgical.com/en/biochemistry/pathways/urea-cycle/)

## Related conditions

- [Obesity](https://durgical.com/en/conditions/obesity/)

## Related

- [Energy requirements and basal metabolic rate (BMR)](https://durgical.com/en/biochemistry/topics/energy-requirements-and-basal-metabolic-rate/)
- [Macronutrients and the energy value of food](https://durgical.com/en/biochemistry/topics/macronutrients-and-the-energy-value-of-food/)
- [Urea cycle](https://durgical.com/en/biochemistry/pathways/urea-cycle/)
- [Protein quality and essential amino acids](https://durgical.com/en/biochemistry/topics/protein-quality-and-essential-amino-acids/)
- [UCP1 (thermogenin)](https://durgical.com/en/biochemistry/enzymes/ucp1/)
- [Fed, fasting and starvation states](https://durgical.com/en/biochemistry/topics/fed-fasting-and-starvation-states/)
- [Leptin, appetite and obesity](https://durgical.com/en/biochemistry/topics/leptin-appetite-and-obesity/)

## Test yourself

Think of the answer, then tap the question to see it.

## Which macronutrient has the largest specific dynamic action, and why?

Protein (about 20–30 % of its energy), mainly because deamination, urea synthesis and gluconeogenesis from amino acids cost ATP.

## About what fraction of daily energy intake is spent as the thermic effect of food on a mixed diet?

About 10 %.

## Why is fat's thermic effect so small?

Dietary triglyceride is stored as triglyceride with little chemical change, so very little ATP is spent processing it.

## How does a recent meal affect a measurement of basal metabolic rate?

It raises it falsely, because the specific dynamic action adds heat production; that is why BMR is measured after a 12-hour fast.

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Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Human energy requirements](https://www.fao.org/4/y5686e/y5686e00.htm) (Food and Agriculture Organization of the United Nations (FAO/WHO/UNU expert consultation), 2004); [Metabolism: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/002257.htm) (MedlinePlus, US National Library of Medicine, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).

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