The Nutrition Hub gives you three numbers in a few seconds. Here is what each one means, so you can use them wisely.
BMI: body mass index
BMI is your weight in kilograms divided by your height in metres squared. For adults, the World Health Organization uses these ranges:
- below 18.5: underweight
- 18.5 to 24.9: healthy range
- 25 to 29.9: overweight
- 30 and above: obesity
The limits: BMI doesn’t know whether weight is muscle or fat, or where fat sits on the body. Athletes often score “overweight” while being very fit. It isn’t meant for children, pregnancy, or comparing very different body types. Use it as a rough screening number, not a diagnosis.
BMR: basal metabolic rate
BMR is the energy your body uses at complete rest: breathing, circulation, keeping warm. It’s often 60–70% of what you burn in a day. Our calculator uses the Mifflin–St Jeor formula, which uses weight, height, age and a female or male adjustment.
TDEE: total daily energy expenditure
TDEE is your BMR plus everything else: walking, work, exercise and digesting food. It’s estimated by multiplying BMR by an activity factor, from 1.2 for mostly sitting to about 1.9 for a physical job plus hard training. Eating about your TDEE keeps weight steady; eating around 500 kcal less a day often leads to losing about half a kilogram (1 lb) a week.
Use them as a starting point
All three are estimates for average bodies. Real needs vary with genetics, sleep, stress, medications and health conditions. A practical approach:
- Start with the calculator’s calorie number.
- Track your food and weight for two to three weeks.
- Adjust by 100–200 kcal based on how your weight actually changes.
Very low calorie goals (under about 1,200 kcal for women or 1,500 for men) are best done with medical support.
Save your numbers
With a free account, save your profile in the Nutrition Hub or in the food diary under My profile, and use the results as your daily goals.
Sources
Informational content only. Not medical advice. Talk to a doctor or registered dietitian about your own needs.