You want to lose weight. Everyone says "eat in a calorie deficit." But what does that actually mean — and how do you figure out YOUR number?
Let's break it down into three simple steps.
What Is a Calorie Deficit?
A calorie deficit means eating fewer calories than your body burns. When you do this, your body uses stored fat for energy. That's how weight loss happens.
Simple math:
- Burn 2,000 calories per day
- Eat 1,500 calories per day
- Deficit = 500 calories
- Result: Gradual weight loss
The key is finding the right deficit — not too small (no results), not too large (unsustainable and unhealthy).
Step 1: Find Your TDEE
TDEE (Total Daily Energy Expenditure) is how many calories you burn per day. This is your starting point.
Quick Estimate Formula
For a rough estimate, multiply your current weight by:
| Activity Level | Multiplier | |----------------|-----------| | Sedentary (desk job, little exercise) | 12-13 | | Lightly active (light exercise 1-3x/week) | 14-15 | | Moderately active (moderate exercise 3-5x/week) | 15-16 | | Very active (hard exercise 6-7x/week) | 17-18 |
Example: You weigh 180 lbs and have a desk job (sedentary).
- 180 × 12 = 2,160 calories (your TDEE estimate)
Want a more accurate number? Read our complete guide on Understanding TDEE.
Step 2: Choose Your Deficit
Now subtract calories from your TDEE. Here's what different deficits look like:
300-400 Calorie Deficit (Gentle)
- Weight loss: ~0.5 lb per week
- Best for: People close to goal weight, those prioritizing muscle retention
- Sustainability: Very high — barely noticeable lifestyle change
500 Calorie Deficit (Moderate)
- Weight loss: ~1 lb per week
- Best for: Most beginners, balanced approach
- Sustainability: Good — sustainable for months
700+ Calorie Deficit (Aggressive)
- Weight loss: ~1.5+ lbs per week
- Best for: Higher starting weights, short-term goals
- Sustainability: Moderate — requires more discipline
Recommendation: Start with a 500-calorie deficit. It's the sweet spot for most people.
Step 3: Track Your Intake
Once you know your target, you need to actually eat that amount. This is where most people struggle.
The tracking equation:
- Your TDEE: 2,160 calories
- Your deficit: -500 calories
- Your target: 1,660 calories per day
Tips for Staying on Track
- Use an app — NutriFox's AI scanner makes logging meals instant. Try it free.
- Track everything — Yes, even that "small" handful of nuts
- Don't obsess — Being within 50-100 calories is good enough
- Adjust monthly — If weight isn't changing, reassess your numbers
Quick Reference: Your Calorie Deficit Cheat Sheet
| Your TDEE | 500-Cal Deficit Target | Expected Weight Loss | |-----------|----------------------|---------------------| | 1,800 | 1,300 | ~1 lb/week | | 2,000 | 1,500 | ~1 lb/week | | 2,200 | 1,700 | ~1 lb/week | | 2,400 | 1,900 | ~1 lb/week | | 2,600 | 2,100 | ~1 lb/week |
Never go below 1,200 calories (women) or 1,500 calories (men) without medical supervision.
3 Common Beginner Mistakes
1. Creating Too Large a Deficit
Cutting 1,000+ calories sounds like "faster results." What actually happens: hunger, fatigue, muscle loss, and eventually quitting.
Fix: Stick to 500 calories max deficit as a beginner.
2. Forgetting Activity Changes
If you start exercising more, your TDEE goes up. If you become less active, it goes down.
Fix: Recalculate every 2-3 months or when your routine changes.
3. Expecting Linear Results
Weight loss isn't perfectly predictable. Water weight, hormones, and food volume cause daily fluctuations.
Fix: Track weekly averages, not daily numbers. Look at trends over 2-4 weeks.
The Simple Formula (Save This)
Your Calorie Target = (Body Weight × Activity Multiplier) - 500
That's it. Calculate once, track consistently, adjust monthly.
Bottom line: A calorie deficit isn't complicated. Find your TDEE, subtract 500, and track your food. The hard part isn't the math — it's the consistency. Start simple, give it 4 weeks, then adjust if needed.
Ready to start tracking? Download NutriFox and let AI do the work — just snap a photo and log meals in seconds.