What is a calorie deficit?

A calorie deficit means eating fewer calories than your body burns in a day. It is the underlying mechanism of all fat loss — when intake is below expenditure, the body makes up the difference from stored energy, including body fat. Paired with resistance training and adequate protein, that lost weight comes predominantly from fat.

How big should my calorie deficit be?

For most men, 250 to 500 calories below maintenance per day — a mild to standard deficit — is the sustainable range. A 750-calorie aggressive deficit can be used for short stretches, especially at higher body fat, but it is harder to sustain and risks muscle loss. Never sit below your BMR for sustained periods.

How much weight will I lose in a calorie deficit?

Roughly one pound of fat per 3,500-calorie cumulative deficit. So a 500-calorie daily deficit projects to about 1 pound per week, 250 per day to about 0.5 pound, and 750 per day to about 1.5 pounds. These are estimates — actual loss varies, so adjust based on a 2-3 week weight trend.

Is a bigger calorie deficit faster?

Faster on the scale, but not better. Too aggressive a deficit strips muscle along with fat, tanks training performance, and is very hard to sustain — which usually ends in regain. A moderate deficit you can hold for months reaches a better, more lasting result than a steep one you quit. Steady is the genuinely fast route.

Why am I not losing weight in a calorie deficit?

Usually the deficit is smaller than you think — untracked calories from oils, drinks, bites, and weekend meals quietly close the gap. It can also be normal 1-2 week fluctuation from water and food volume. Track intake honestly, judge by a 2-3 week weight trend rather than day to day, and recalibrate if the trend is flat.

Free tool

Calorie deficit calculator

Find your maintenance calories, then a mild, standard, or aggressive deficit target — each with the fat loss it projects per week. Built for men 25-40. No signup. No email gate.

How it works

The calculator finds your BMR with the Mifflin-St Jeor equation, multiplies by an activity factor for your TDEE (maintenance), then subtracts a deficit: 250, 500, or 750 calories. Projected weekly loss assumes roughly 3,500 calories per pound of fat.

These are starting estimates, accurate to about ±10%. Run a deficit for 2-3 weeks, then adjust to your actual weight trend — losing faster than projected, eat a little more; flat, trim a little. The calculator points the direction; your trend confirms the number.

Want a coach to calibrate the deficit for you?

The number is the easy part. The work is the weekly adjustment — reading your weight trend, training, sleep, and stress, then knowing what to change so you lose fat without losing muscle. That is what 1:1 coaching with Kris is for.

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