Deficitly
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How can you boost your metabolism?
The one change that reliably burns a lot more is moving more during the day: going from 4,000 to 9,000 steps a day adds about 130 calories for a woman of 70 kg (154 lb) and 170 for a man of 85 kg (187 lb). Strength training adds a little during the sessions and keeps the muscle that sets your resting burn; protein costs more to digest than carbs or fat; and sleep keeps your appetite and energy in check. "Metabolism-boosting" foods, drinks and supplements add a few calories at most.
What each change adds a day
| Change | Woman70 kg | Man85 kg |
|---|---|---|
| 4,000 → 9,000 steps a day | 130 | 170 |
| Weights 3 × 45 min a week | 60 | 80 |
| 2 kg (4.4 lb) more muscle | 30 | 30 |
| 300 kcal of carbs swapped for protein | 50 | 50 |
| Green tea, chilli, cold water | a few | a few |
Steps come out on top and scale furthest: you can add steps every day, while lifting is limited by recovery. That's also why Deficitly builds your burn from your step count: see what is NEAT?
1. Move more outside the gym
NEAT, the energy of everything that isn't sleeping, eating or sport, is the part of metabolism that differs most between people of the same size: by up to 2,000 calories a day between a desk worker and someone on their feet all day. Walking breaks, standing while on the phone, taking stairs, walking to the shops and a daily walk all count. A step counter makes it measurable, and every 1,000 steps shows up in your maintenance calories: see how many steps a day to lose weight.
2. Build and keep muscle
Muscle burns about three times as much as fat at rest, but the numbers are smaller than gym lore suggests: about 13 calories per kg a day, so even 2 kg of new muscle adds 30. The bigger value of strength training is keeping muscle while you diet and as you age, so your BMR doesn't drop more than it has to (does metabolism slow with age?). See calories burned lifting weights.
3. Eat enough protein
Your body uses about 25% of protein's calories to digest and process it, against about 7.5% for carbs and almost nothing for fat. Swapping 300 calories of carbs for protein burns about 50 more a day. Protein also keeps you fuller and protects muscle while dieting, which matters more. See thermic effect of food and the protein calculator.
4. Sleep enough
Short sleep barely changes what you burn, but it changes what you eat: in a meta-analysis of sleep-restriction studies, people ate about 385 calories a day more after short nights. Tired people also move less. Seven hours or more is the cheapest metabolism fix there is.
5. Don't diet too hard for too long
Losing weight lowers your burn because a smaller body costs less to run, and a long, hard diet lowers it a little further and cuts your daily movement. A moderate deficit, high protein, lifting and steps limit the drop; breaks at maintenance can help (weight-loss plateau, reverse dieting).
What doesn't boost your metabolism
- Eating small meals often. Digestion costs the same share of what you eat whether it comes in 2 meals or 6.
- Green tea, coffee, chilli, apple cider vinegar. Caffeine and capsaicin cause a small, short rise, tens of calories at most; the rest have no real effect.
- Cold water. Warming a glass to body temperature costs a few calories.
- "Fat-burning" supplements. None has shown a meaningful long-term effect, and some are unsafe.
- The "afterburn". Hard workouts raise your burn for a few hours afterwards, but usually by a few dozen calories, not hundreds.
Is your metabolism actually slow?
Probably less than you think: adjusted for size, most adults burn within about 10% of the prediction, and metabolism holds fairly steady from 20 to 60. You can check yours from what you eat and how your weight changes: signs of a fast or slow metabolism.
Sources
- Levine JA. Non-exercise activity thermogenesis (NEAT). Best Pract Res Clin Endocrinol Metab 2002;16(4):679–702.
- Elia M. Organ and tissue contribution to metabolic rate. In: Kinney JM, Tucker HN, eds. Energy Metabolism: Tissue Determinants and Cellular Corollaries. Raven Press, 1992:61–79.
- Westerterp KR. Diet induced thermogenesis. Nutr Metab (Lond) 2004;1(1):5.
- Al Khatib HK, Harding SV, Darzi J, Pot GK. The effects of partial sleep deprivation on energy balance: a systematic review and meta-analysis. Eur J Clin Nutr 2017;71(5):614–624.
- Bellisle F, McDevitt R, Prentice AM. Meal frequency and energy balance. Br J Nutr 1997;77(Suppl 1):S57–S70.
- Pontzer H, Yamada Y, Sagayama H, et al. Daily energy expenditure through the human life course. Science 2021;373(6556):808–812.
- Herrmann SD, Willis EA, Ainsworth BE, et al. 2024 Adult Compendium of Physical Activities: A third update of the energy costs of human activities. Journal of Sport and Health Science, 2024;13(1):6-12. doi:10.1016/j.jshs.2023.10.010