Calorie Needs by Age and Sex: The NIH Estimated Energy

What the EER is

The Estimated Energy Requirement (EER) is the NIH / Institute of Medicine equation for how many calories a person needs to maintain weight, given age, sex, height, weight, and physical activity. It is the math behind most TDEE calculators, including VivMetric’s own.

The simplified formula

For adults, EER starts from Basal Metabolic Rate (BMR) using the Mifflin–St Jeor equation, then multiplies by an activity factor:

Men: BMR = 10·weight(kg) + 6.25·height(cm) − 5·age + 5

Women: BMR = 10·weight(kg) + 6.25·height(cm) − 5·age − 161

Maintenance ≈ BMR × activity factor (about 1.2 sedentary to 1.9 very active).

Example maintenance ranges by age and sex

Using a reference adult of about 170 lb (77 kg) and 5'9" (175 cm), sedentary-to-moderately-active maintenance lands roughly in these bands. These are NIH/Mayo-style reference ranges, not your personal number — your result scales with height, weight, and activity:

Men 19–30: ~2,400–3,000 kcal/day

Men 31–50: ~2,200–2,800 kcal/day

Men 51–70: ~2,000–2,600 kcal/day

Women 19–30: ~1,800–2,400 kcal/day

Women 31–50: ~1,800–2,200 kcal/day

Women 51–70: ~1,600–2,200 kcal/day

Why your number moves

Calorie needs fall with age (loss of lean mass), rise with muscle and activity, and shift with pregnancy, illness, or a weight goal. A diet below about 1,200 kcal/day (women) or 1,500 kcal/day (men) usually warrants professional supervision.

How to use it

Treat the EER as a maintenance baseline. Subtract about 500 kcal/day for roughly 1 lb/week of loss, add for gain, and recompute when weight or activity changes. Use VivMetric’s TDEE tool to run your own numbers instead of guessing from a table.