Fat-loss guide
What is a calorie deficit?
Last updated: July 10, 2026
Short answer: a calorie deficit means eating fewer calories than your body burns, so it uses stored fat to make up the difference — this is the only way to lose fat. A ~500/day deficit loses about 1 lb a week. Find your maintenance calories first, then subtract: use thefree calorie deficit calculator.
Every diet that works — keto, low-carb, fasting, portion control — works for the same underlying reason: it puts you in a calorie deficit. Understand this one idea and you no longer need to chase diets; you need a number and a way to hit it consistently.
The science, briefly
Your body spends energy every day — on basic functions (your BMR), digestion, and movement. Add those up and you get yourtotal daily energy expenditure (TDEE), also called yourmaintenance calories. Eat at maintenance and your weight holds. Eat below it and your body draws on stored energy — primarily body fat — to cover the gap. That gap is the deficit, and it is what drives fat loss.
How big should the deficit be?
| Daily deficit | Weekly loss | Best for |
|---|---|---|
| 250 kcal | ~0.5 lb (0.25 kg) | Lean people, "recomp", minimal muscle loss |
| 500 kcal | ~1 lb (0.45 kg) | The sustainable default for most people |
| 750-1,000 kcal | ~1.5-2 lb (0.7-0.9 kg) | Higher body fat, short-term, with high protein |
A useful rule is 0.5-1% of your body weight per week. Faster isn't better — aggressive deficits are hard to sustain, cost you more muscle, and often end in rebound eating. Don't go below roughly 1,200 kcal/day (women) or 1,500 (men)without medical guidance.
How to create your deficit
- Find your maintenance number. Get your TDEE from the TDEE calculator, then subtract your chosen deficit — or let the deficit calculator do both.
- Eat mostly from the deficit, not exercise. It's far easier to not eat 500 calories than to burn 500 — use food as the main lever and movement as a bonus.
- Keep protein high. 1.6-2.2 g/kg of body weight protects muscle so the weight you lose is fat. See calories in protein, carbs & fat.
- Track honestly. Untracked oils, drinks, and "bites" are why most deficits fail. Logging by photo or barcode is far more accurate than eyeballing.
Why the scale stalls
Two things fool people. First, water weight hides fat loss — a stressful week, salty meal, or new workout can add a couple of pounds of water even as fat drops. Second, your maintenance calories fall as you get lighter, so a deficit that worked at the start shrinks over time. Weigh under consistent conditions, judge the trend over 2-3 weeks (not day to day), and recalculate every 4-6 kg of loss.
Track your deficit automatically
The hardest part of a deficit isn't the math — it's logging accurately, every day. TheMyPlate app calculates your target and lets you log meals by photo or barcode in seconds, so your real deficit is visible instead of guessed. Preview your number with thefree calorie calculator, then checkhow many calories you should eat a day.
Frequently asked questions
What is a calorie deficit?
A calorie deficit means eating fewer calories than your body burns each day. When you do this consistently, your body makes up the difference by using stored energy — mostly body fat — so you lose weight. It is the one thing every diet has in common, whether it is keto, low-carb, intermittent fasting, or just smaller portions. There is no way to lose fat without an overall calorie deficit.
How big should my calorie deficit be?
A deficit of about 500 calories a day is the standard, sustainable target — it produces roughly 1 lb (0.45 kg) of fat loss per week, since about 3,500 calories equals a pound of fat. A 750-1,000/day deficit loses faster (1.5-2 lb/week) but is harder to stick to and risks muscle loss. Aim for 0.5-1% of your body weight per week, and never drop below about 1,200 calories (women) or 1,500 (men) without medical supervision.
How many calories do I need to lose a pound?
Roughly 3,500 calories equals one pound of body fat, so a 500-calorie daily deficit (500 × 7 = 3,500) loses about a pound a week. This is an average, not an exact law — water weight, sodium, and muscle changes make the scale bounce day to day — but over weeks the math holds up well.
How do I lose belly fat specifically?
You cannot spot-reduce fat — no exercise or food burns fat from one area. Belly fat comes off as part of overall fat loss driven by a calorie deficit. What helps: a moderate deficit, enough protein, resistance training to keep muscle, adequate sleep, and managing stress (high cortisol is linked to abdominal fat). Visceral belly fat often responds well early once you are consistently in a deficit.
Why am I in a calorie deficit but not losing weight?
The most common reasons are underestimating intake (untracked bites, oils, drinks, and larger-than-labelled portions), water retention masking fat loss on the scale, or a deficit that is smaller than you think because your maintenance calories dropped as you lost weight. Track honestly for two weeks, weigh yourself under consistent conditions, and recalculate your target — an app that logs by photo or barcode makes this far more accurate than guessing.
Can I lose fat without exercise?
Yes — fat loss is driven by the calorie deficit, so you can lose weight through diet alone. But exercise, especially resistance training, helps you keep muscle while you lose fat (so more of the loss is fat, not muscle), burns extra calories, and improves health. The best results come from a deficit plus strength training and enough protein.