Key Takeaways
- A calorie deficit occurs when you consume fewer calories than your body burns
- 1 kg of body fat = 7,700 calories - this is the basis for weight loss calculations
- Safe weight loss is 0.5-1 kg per week (500-1,000 calorie daily deficit)
- Never go below 1,200 calories (women) or 1,500 calories (men) per day
- Combine calorie deficit with exercise for best results and muscle preservation
What Is a Calorie Deficit?
A calorie deficit occurs when you consume fewer calories than your body needs to maintain its current weight. Your body then uses stored fat for energy, resulting in weight loss. This is the fundamental principle behind all successful weight loss programs.
Your Total Daily Energy Expenditure (TDEE) represents the total number of calories your body burns in a day, including your basal metabolic rate (BMR) plus the calories burned through physical activity and digestion.
Daily Deficit = Weekly Weight Loss Goal (kg) x 7,700 / 7
How to Use This Calculator
- Enter your TDEE: Your Total Daily Energy Expenditure. If you don't know it, use our TDEE Calculator first.
- Set your weight loss goal: Choose how much weight you want to lose per week (0.5-1 kg is recommended).
- Click Calculate: The calculator will show your daily calorie target and deficit.
- Follow the plan: Eat at your daily calorie target to achieve your weight loss goal.
Understanding Your Results
The calculator provides three key numbers:
- Daily Calorie Target: The number of calories you should consume each day to lose weight at your desired rate.
- Daily Deficit: How many fewer calories than your TDEE you'll be consuming.
- Weekly Deficit: The total calorie deficit over a week, which determines your weight loss.
Important Safety Warning
Never consume fewer than 1,200 calories per day (women) or 1,500 calories per day (men) without medical supervision. Extremely low calorie diets can lead to nutrient deficiencies, muscle loss, metabolic slowdown, and other health problems.
Safe vs. Aggressive Deficits
Safe Deficit (250-500 cal/day)
- Weight loss: 0.25-0.5 kg per week
- Sustainable long-term
- Minimal muscle loss
- Easier to maintain energy levels
- Best for those with less weight to lose
Moderate Deficit (500-750 cal/day)
- Weight loss: 0.5-0.75 kg per week
- Good balance of speed and sustainability
- May require more attention to protein intake
- Suitable for most people
Aggressive Deficit (750-1,000 cal/day)
- Weight loss: 0.75-1 kg per week
- Maximum recommended rate
- Requires careful nutrition planning
- May be harder to sustain
- Best for those with significant weight to lose
Pro Tip: The 80/20 Rule
Weight loss is approximately 80% diet and 20% exercise. While both are important, focus primarily on maintaining your calorie deficit through nutrition. Exercise helps preserve muscle mass, improves health, and creates a larger deficit - but you can't out-exercise a bad diet.
Tips for Maintaining a Calorie Deficit
- Track your food: Use a food diary or app to monitor calorie intake accurately.
- Prioritize protein: Aim for 1.6-2.2g of protein per kg of body weight to preserve muscle.
- Eat whole foods: They're more filling and nutrient-dense than processed foods.
- Stay hydrated: Sometimes thirst is mistaken for hunger.
- Plan meals ahead: Reduces impulsive eating and makes tracking easier.
- Include fiber: Keeps you full longer and supports digestive health.
- Get enough sleep: Poor sleep increases hunger hormones and cravings.
- Be patient: Sustainable weight loss takes time - aim for consistency, not perfection.
Frequently Asked Questions
A safe calorie deficit is typically 500-1,000 calories per day, resulting in 0.5-1 kg of weight loss per week. Deficits larger than 1,000 calories daily are not recommended as they can lead to muscle loss, nutrient deficiencies, and metabolic adaptation.
TDEE is calculated by multiplying your Basal Metabolic Rate (BMR) by an activity factor. Use our TDEE Calculator for an accurate estimate based on your age, gender, weight, height, and activity level.
Common reasons include: underestimating calorie intake (hidden calories in sauces, drinks, oils), overestimating TDEE, water retention masking fat loss, metabolic adaptation from prolonged dieting, or not being in a true deficit. Try tracking food more accurately and consider a diet break if you've been dieting for months.
It depends. If your TDEE already includes your exercise, don't eat them back. If you calculated a sedentary TDEE and added exercise, you may eat back 50-75% of exercise calories (fitness trackers often overestimate). For most people, it's simpler to use a TDEE that includes average activity.
For sustainable results, follow a deficit for 8-16 weeks, then take a 1-2 week "diet break" at maintenance calories. This helps prevent metabolic adaptation and psychological burnout. Repeat cycles as needed until you reach your goal weight.
Prolonged severe deficits can cause "metabolic adaptation" where your body burns fewer calories. To minimize this: use moderate deficits, include resistance training, eat adequate protein, take periodic diet breaks, and avoid crash diets. Your metabolism largely recovers when you return to maintenance calories.