Hvilestoffskifte, TDEE og kaloriunderskudd: de 3 tallene som avgjør vekttap

Hvorfor kaloriekuttet ditt sluttet å virke

Here is the most common diet story. You cut to 1,200 calories. You lose for three weeks. Then the scale stops, you feel cold, tired and ravenous, and you blame yourself. The problem is almost never willpower. It is that “calories” is not one number — it is three, and they get mixed up. Your basal metabolic rate (BMR), your total daily energy expenditure (TDEE) and your deficit are three separate figures. Cut against the wrong one and the body fights back: it lowers the energy it spends to match the little you give it (a real effect called metabolic adaptation, Hall 2012). The fix is not eating less. It is knowing your three numbers.

De tre tallene, i rekkefølge

Hvilestoffskifte — hva du forbrenner uten å gjøre noe

Your BMR is the energy your body burns doing absolutely nothing — keeping your heart beating, your brain running, your temperature steady. For most adults it is 1,300-1,800 kcal a day, and it is the biggest single chunk of what you burn: 60-70% of the total. You calculate it from height, weight, age and sex. The key rule: eating below your BMR for weeks is the trap. It triggers the adaptation that stalls weight loss and costs you muscle, hair and (for women) regular periods.

→ Calculate your BMR

TDEE — hva du faktisk forbrenner på en dag

Your TDEE is BMR plus everything you do: walking, working, training, even fidgeting. It is your BMR multiplied by an activity factor (1.2 for sedentary up to ~1.9 for very active). For a sedentary 1,500-kcal-BMR person, TDEE is around 1,800; for an active one it can be 2,800. This is your maintenance number — eat at TDEE and your weight holds. Most people overestimate their activity factor, which is why “I barely eat and don’t lose” is usually a TDEE miscalculation, not a broken metabolism. The macro calculator gives you TDEE plus a protein/carb/fat split.

→ Calculate your TDEE and macros

Underskuddet — det eneste tallet som flytter vekten

The deficit is the only number that actually moves the scale: it is TDEE minus what you eat. A deficit of about 500 kcal/day yields roughly 0.5 kg of fat loss per week — the rate every major guideline considers sustainable. Bigger is not better: aggressive deficits accelerate muscle loss and the adaptation that stalls you. The sweet spot for most people is a deficit of 15-25% below TDEE, never dropping intake below BMR. Set the deficit against your TDEE — not against a random 1,200 — and the scale moves without the body fighting back.

Mifflin-St Jeor mot Harris-Benedict: formelen som vinner

This is the question people actually search for, so here is the straight answer. Two formulas estimate BMR: Harris-Benedict (1919, revised 1984) and Mifflin-St Jeor (1990). Mifflin-St Jeor wins. The decisive study is Frankenfield 2005 (J Am Diet Assoc), which compared the equations against measured metabolic rate and found Mifflin-St Jeor was accurate within 10% for the most people — beating Harris-Benedict, which tends to overestimate by around 5%. That 5% is roughly 90 kcal a day: enough to erase a careful deficit. Every calculator on this page uses Mifflin-St Jeor for that reason. (Body-composition formulas like Katch-McArdle can edge it out if you know your body-fat percentage — see below.)

Hvorfor vekten lyver — og hva du bør følge i stedet

The scale measures everything: fat, muscle, water, glycogen, the meal you just ate. A whoosh of water can hide two weeks of real fat loss, which is why people quit just before the scale catches up. Three better signals: a tape measure at the waist, body-fat percentage, and the waist-to-hip ratio. If your waist is shrinking while the scale stalls, you are losing fat and holding muscle — exactly the goal. Track those alongside weight and you stop quitting at the wrong moment.

→ Body-fat calculator · Waist-to-hip ratio · BMI calculator

Relaterte kalkulatorer

• Hvilestoffskifte-kalkulator
• Makro-kalkulator
• Kroppsfett-kalkulator
• Midje-hofte-forhold
• BMI-kalkulator