How Many Calories Should You Cut to Lose Weight?
How Many Calories Should You Cut to Lose Weight?
Losing weight comes down to one core principle: eating fewer calories than your body burns, known as a calorie deficit. But “eat less” isn’t a useful plan on its own — the size of your deficit determines how fast you lose weight, whether you keep muscle, and whether the diet is sustainable long enough to work.
This guide walks through exactly how to calculate a calorie deficit, how many calories to cut for different weight-loss goals, and the mistakes that cause most people’s deficits to stall out.
What Is a Calorie Deficit, Exactly?
A calorie deficit simply means you’re consuming fewer calories than your body needs to maintain its current weight. That “maintenance” number is called your Total Daily Energy Expenditure (TDEE) — it includes your resting metabolism, digestion, daily movement, and exercise.
If your TDEE is 2,400 calories and you eat 2,000, you’re in a 400-calorie daily deficit. Over time, that gap is what drives fat loss.
The Math: Calories to Pounds
One pound of body fat is roughly equal to 3,500 calories. That number isn’t perfectly precise (more on that below), but it’s the standard rule of thumb used to plan a deficit:
| Target Weekly Loss | Weekly Deficit Needed | Daily Deficit Needed |
|---|---|---|
| 0.5 lb/week | 1,750 calories | ~250 calories/day |
| 1 lb/week | 3,500 calories | ~500 calories/day |
| 1.5 lb/week | 5,250 calories | ~750 calories/day |
| 2 lb/week | 7,000 calories | ~1,000 calories/day |
Most nutrition guidelines recommend staying in the 0.5–2 lb per week range. Faster than that, and the deficit usually gets too aggressive to sustain — or starts costing you muscle instead of just fat.
Step 1: Find Your Maintenance Calories (TDEE)
Before you can create a deficit, you need to know your maintenance number. The most common way to estimate it:
- Calculate your Basal Metabolic Rate (BMR) — the calories your body burns at rest, using a formula like Mifflin-St Jeor (based on weight, height, age, and sex).
- Multiply by an activity factor — sedentary (1.2), lightly active (1.375), moderately active (1.55), very active (1.725).
Example: A 35-year-old woman, 5’6″, 160 lbs, moderately active, has a BMR of roughly 1,470 calories. Multiplied by 1.55, her TDEE lands around 2,280 calories/day — that’s her maintenance number, and her starting point for a deficit.
Step 2: Pick a Sustainable Deficit Size
This is where most people go wrong — they pick the biggest deficit possible instead of the one they can actually stick to. A few guidelines:
- 250–500 calories/day is the sweet spot for most people: noticeable progress without constant hunger or energy crashes.
- 750+ calories/day can work short-term but gets harder to sustain and raises the risk of muscle loss, especially without adequate protein and resistance training.
- Never go below your BMR — cutting calories below what your body needs just to function at rest tends to backfire through fatigue, muscle loss, and metabolic slowdown.
Why the “3,500 Calories = 1 Pound” Rule Isn’t Perfectly Accurate
The 3,500-calorie rule is a useful planning tool, but real-world weight loss doesn’t move in a perfectly straight line for a few reasons:
- Your TDEE drops as you lose weight — a lighter body burns fewer calories, so a 500-calorie deficit today won’t stay a 500-calorie deficit at a lower weight without adjusting intake.
- Water weight fluctuates daily — sodium intake, carb intake, and hormonal cycles can shift the scale by 2–5 lbs independent of fat loss.
- Not all weight lost is fat — especially in an aggressive deficit without strength training, some of the loss can come from muscle.
This is why tracking trends over 2–3 weeks (not day-to-day scale readings) gives a much more accurate picture of whether your deficit is working.
Signs Your Deficit Is Too Aggressive
- Constant fatigue or difficulty concentrating
- Losing more than 1% of body weight per week consistently
- Strength going down noticeably in the gym
- Persistent hunger that leads to overeating later
If several of these show up, increasing calories by 100–200/day is usually a better long-term move than pushing through.
Quick Example: Putting It All Together
Using the 35-year-old woman from earlier with a TDEE of ~2,280 calories:
- Goal: Lose 1 lb/week
- Deficit needed: ~500 calories/day
- Target intake: 2,280 − 500 = 1,780 calories/day
That number becomes her daily calorie target — adjusted every few weeks as her weight (and TDEE) changes.
Frequently Asked Questions
Is a 1,000-calorie deficit too much?
For most people, yes — it typically means eating well below maintenance and often below BMR, which raises the risk of fatigue, muscle loss, and rebound overeating. It may only be appropriate short-term and under medical guidance.
How often should I recalculate my deficit?
Every 10–15 lbs lost, or every 4–6 weeks, since your TDEE decreases as your weight drops.
Does exercise change how big my deficit should be?
Exercise raises your TDEE, which means you can eat more while maintaining the same deficit — it doesn’t require cutting calories further.
Use our BMI Chart by Age and Gender to see how your current weight compares to healthy ranges, or check out our [weight converter link] to convert between kg and lbs as you track progress.