Why Mifflin-St Jeor instead of Harris-Benedict?
Multiple studies comparing the two found Mifflin-St Jeor (1990) more statistically accurate for most healthy adults today, while Harris-Benedict (1919) tends to overestimate BMR since it was built on older data with different typical body compositions. Most modern clinical sources use Mifflin-St Jeor as the default.
Is the macro split suitable for athletes?
The split here (1.8 g/kg bodyweight protein, 25% of calories from fat, the rest carbs) is a solid starting point for most active people. Professional athletes or those doing intense strength training may need more protein (up to 2.2 g/kg) — consult a sports dietitian for a personalized plan.
Will I actually lose weight eating this many calories?
The result is a statistical estimate from a general formula and may differ from your true need by 10-15% depending on individual factors (genetics, hormones, actual muscle mass). Use the number as a starting point, track your real weight for two weeks, and adjust calories up or down based on the actual outcome.
Is this calculator suitable for pregnant women, children, or people with an eating disorder?
No. Pregnant and breastfeeding women have additional calorie needs this formula doesn't account for; children and teens (under 18) need a different assessment to support growth; and anyone with a history of an eating disorder should work with a specialist rather than relying on a general calculator.
What's the lowest safe daily calorie amount?
As a general rule, going below 1,200 calories for women or 1,500 for men isn't recommended without direct medical supervision, and you should never go below your calculated BMR — the body needs at least that much even at complete rest.
