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Calorie needs by life stage
How many calories and how much protein you need in pregnancy, while breastfeeding, as a teenager, after 65, around menopause, in endurance training and at a desk — each with its own worked example.
General information only. These are population reference values, not a plan for you. Pregnancy, adolescence, illness, medication and eating-disorder history all change energy and protein needs in ways this page cannot see — a midwife, doctor or registered dietitian individualises them.
Start here: BMR, PAL and TDEE
Three numbers sit behind every calorie figure on this site, and they are worth separating because people mix them up constantly.
BMR — basal metabolic rate. What your body spends at complete rest, doing nothing but staying alive: breathing, circulation, brain, kidneys, cell turnover. For most adults it is the largest single component of the day, usually somewhere between 60% and 70% of total expenditure.
PAL — physical activity level. A multiplier that converts a resting figure into a real day. WHO/FAO and EFSA both use it. Sedentary sits near 1.4; a physically demanding job plus training reaches 2.0 and beyond.
TDEE — total daily energy expenditure. BMR × PAL, plus any life-stage increment. This is the number you actually eat against.
The equation, written out
This site uses Mifflin-St Jeor, which is the equation most clinical and public references default to for adults:
BMR (men) = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
BMR (women) = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
TDEE = BMR × PAL + life-stage incrementTwo honest caveats. It was derived in adults, so it is not the equation reference bodies use for children and adolescents — they use age-specific equations plus an allowance for the energy laid down as new tissue during growth. And it predicts a population average: individual resting expenditure varies around the prediction by roughly ten per cent in either direction, more at very high and very low body weights.
Physical activity levels
| PAL | What it describes | Woman 70 kg / 168 cm / 40 | Man 80 kg / 180 cm / 40 |
|---|---|---|---|
| 1.4 | Sedentary or low activity — desk work, little planned exercise | 1 945 | 2 422 |
| 1.6 | Moderately active — some walking, light training two or three times a week | 2 222 | 2 768 |
| 1.8 | Active — on your feet at work, or training most days | 2 500 | 3 114 |
| 2.0 | Very active — physical job plus training, or high training volume | 2 778 | 3 460 |
Source: Human energy requirements — Joint FAO/WHO/UNU Expert Consultation (physical activity level framework) · checked 2026-09-02
Work out your own baseline
Calculate it for your own body
JavaScript is off, so use the worked-example tables on this page — they are computed on the server from the same equation.
Protein band on this page: the general adult reference intake of 0.83 g of protein per kg of body weight a day
Every life stage
Pregnancy and after
Pregnancy, first trimester
about +70 kcal a day on top of the pre-pregnancy requirement
Pregnancy, second trimester
about +260 kcal a day on top of the pre-pregnancy requirement
Pregnancy, third trimester
about +500 kcal a day on top of the pre-pregnancy requirement
Breastfeeding
about +500 kcal a day while breastfeeding exclusively
Growth
Teenage boys (14-18)
no fixed increment — growth is handled through activity level and the growth spurt, not a flat addition
Teenage girls (14-18)
no fixed increment — growth is handled through activity level and the growth spurt, not a flat addition
Later life
Adults over 65
no addition — the requirement falls with lean mass and activity, while the protein target rises
Menopause and perimenopause
no separate energy reference value — menopause changes body composition and symptoms, not the equation
Training load
Endurance athletes
no flat addition — training energy is added session by session, because that is how it is actually spent
Desk workers
no addition — a desk job sets a low physical activity level, and the whole story is in that multiplier
What this page cannot do
Reference values describe populations. They are built by measuring a lot of people and publishing the intake that would meet the needs of almost all of them. That makes them excellent for planning a food supply and mediocre for planning your Tuesday. Two people matched on age, sex, height and weight can differ by several hundred kilocalories a day in measured expenditure, and no equation on any website can tell you which of them you are.
The way through that is not a better equation. It is a starting estimate, a couple of weeks of consistent records, and an adjustment based on what actually happened to your weight, energy and training. That is a loop, and loops beat formulas.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is what your body spends at complete rest keeping you alive. TDEE is BMR multiplied by a physical activity level, so it is what a real day costs. Every figure on this site is TDEE unless it says otherwise.
Which equation does this site use?
Mifflin-St Jeor, the same equation the calculators section uses: 10 × weight in kg + 6.25 × height in cm − 5 × age, then +5 for men or −161 for women. It was derived and validated in adults.
How accurate is a calorie estimate?
A prediction equation typically lands within about 10% of measured resting expenditure for most people, and is worse at the extremes of body size. Treat the output as a starting point you then adjust from what actually happens.
Are these numbers medical advice?
No. They are population reference values and arithmetic. Pregnancy, adolescence, illness and medication all change requirements in ways a public web page cannot see.
Source: EFSA Dietary Reference Values — energy, protein and micronutrients (European Food Safety Authority) · checked 2026-09-02
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