Calculating your calorie needs: how much energy do you really need?
Basal metabolic rate, activity, calorie deficit: how your energy needs add up, how to estimate them roughly and why calculators are only a guide.
- calories
- energy needs
- nutrition
In short
Your daily energy need combines your basal metabolic rate at rest with the extra used through movement. Online calculators estimate it with formulas but are often off for an individual.
Treat the result as a starting point and watch how your body responds over a few weeks.
What your needs consist of
Basal metabolic rate is the energy your body needs for breathing, heartbeat and organs. It depends mainly on height, weight, age, sex and muscle mass.
On top comes energy for movement, exercise and digestion. The German Nutrition Society describes this with the PAL value, reflecting daily physical activity. Basal rate times PAL gives a rough estimate of your total need.
A calorie deficit, in moderation
To lose weight, the body has to use more energy than it takes in. A moderate deficit is easier to sustain than drastic dieting and better protects muscle.
Very low calorie intake over longer periods should only happen under medical guidance. Make sure you get enough protein, fibre and nutrients too, especially when your appetite is low.
Practical tips
- Use calculators as a guide, not a rule
- Log what you eat honestly for a few days to get a feel for it
- Look at your weekly average weight, not daily readings
- When building muscle, weight may stall even while you lose fat
Note
This Journal article offers general information. It is not a diagnosis, a prescription or a promise of any result. Whether treatment is suitable for you is decided by a doctor after reviewing your questionnaire. For acute or severe symptoms, contact your GP, the out-of-hours medical service (116117) or, in an emergency, 112.
Sources and medical review
Based on the D-A-CH reference values for energy intake from the German Nutrition Society and the German S3 obesity guideline. Medical review pending.
- German Nutrition Society (DGE): D-A-CH reference values, energy
- German S3 guideline on prevention and treatment of obesity