# How Many Calories Do You Need a Day?

Most adult women maintain their weight on roughly 1,600 to 2,400 kcal a day and most adult men on roughly 2,000 to 3,000 kcal, depending on age, height, weight and daily movement. To lose fat, eat about 300 to 500 kcal below your personal maintenance; to build muscle, eat slightly above it. Averages are a poor guide because two healthy adults can differ by 1,000 kcal a day, so calculate your own number: estimate your resting metabolism with the Mifflin-St Jeor formula, multiply by an activity factor, and adjust based on what your weekly-average weight does over two to three weeks.

Most answers you find online are averages that can miss your real needs by 1,000 kcal. Here is what actually determines your number, how to calculate it in two minutes, and how to set it for losing, holding or gaining weight without wrecking your muscle.

## On this page

- The short answer: realistic ranges for women and men
- BMR vs. maintenance (TDEE): the two numbers that matter
- How to calculate your calories, with a worked example
- How many calories to lose weight?
- How many calories to build muscle?
- The number nobody asks about: your protein target
- Why every source tells you something different
- Your next step: calculate, then verify

## FAQ

- How many calories should a woman eat a day?
- How many calories should a man eat a day?
- How many calories do I need to lose 1 kg per week?
- Is 1,200 calories a day enough?
- Do I need to eat back the calories I burn during exercise?
- Why am I not losing weight in a calorie deficit?

## Sources

- Institute of Medicine. (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. The National Academies Press. https://doi.org/10.17226/10490
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. (1990). A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition. https://doi.org/10.1093/ajcn/51.2.241
- Frankenfield D, Roth-Yousey L, Compher C. (2005). Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association. https://doi.org/10.1016/j.jada.2005.02.005
- Helms ER, Aragon AA, Fitschen PJ. (2014). Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the International Society of Sports Nutrition. https://doi.org/10.1186/1550-2783-11-20
- Garthe I, Raastad T, Refsnes PE, Koivisto A, Sundgot-Borgen J. (2011). Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes. International Journal of Sport Nutrition and Exercise Metabolism. https://doi.org/10.1123/ijsnem.21.2.97
- Jensen MD, Ryan DH, Apovian CM, et al.. (2014). 2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults. Circulation. https://doi.org/10.1161/01.cir.0000437739.71477.ee
- Hall KD, Sacks G, Chandramohan D, Chow CC, Wang YC, Gortmaker SL, Swinburn BA. (2011). Quantification of the effect of energy imbalance on bodyweight. The Lancet. https://doi.org/10.1016/S0140-6736(11)60812-X
- Jäger R, Kerksick CM, Campbell BI, et al.. (2017). International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition. https://doi.org/10.1186/s12970-017-0177-8
- Morton RW, Murphy KT, McKellar SR, et al.. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine. https://doi.org/10.1136/bjsports-2017-097608

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