Is a Calorie Deficit?
A calorie deficit is a state in which you consume fewer calories than your body uses per day. It is the only scientifically proven way to lose weight. When the body does not get enough energy from food, it starts using stored fat.
One kilogram of body fat corresponds to approximately 7 700 kcal. This means that to lose 0,5 kg per week, you need to create a weekly deficit of about 3 850 kcal or ~550 kcal per day.
🧮 How to Calculate Your Calorie Deficit?
To determine the right deficit, you first need to know your TDEE (Total Daily Energy Expenditure) — how many calories your body burns per day:
- Calculate BMR (basal metabolic rate) — the calories needed at rest. The Mifflin-St Jeor formula is the most accurate.
- Multiply BMR by the activity factor (1,2–1,9) to get TDEE.
- Subtract the deficit: 300–500 kcal less than TDEE = safe and sustainable weight loss.
| Goal | Daily Deficit | Weekly Weight Change |
|---|---|---|
| Slow, Sustainable Loss | 200–300 kcal | ~0,2–0,3 kg |
| Moderate (Recommended) | 500 kcal | ~0,5 kg |
| Aggressive (MAX 4–6 weeks) | 750–1000 kcal | ~0,7–1,0 kg |
| Too Large (NOT RECOMMENDED) | >1000 kcal | Muscle Loss |
⚠️ Most Common Mistakes When Calculating a Deficit
🚫 Too Large a Deficit
Many people think that the larger the deficit, the faster the weight will drop. In reality: too large a deficit slows metabolism, increases cortisol and promotes muscle breakdown.
📱 Incorrect Calorie Counting
There is evidence that people on average underestimate their calorie intake by 20–30% and overestimate their physical activity. Use food scales and apps.
🥩 Insufficient Protein Intake
During a deficit, the body tends to break down muscle. Sufficient protein intake (1,6–2,2 g/kg body weight) helps preserve muscle mass.
🍔 "Cheat Days" Without Control
One "free" day can easily cancel out the entire week's deficit. One restaurant burger with fries and dessert = 1500–2000 kcal.
💡 Practical Tips for Sustaining Deficits
- Eat More Protein and Fiber — they provide a feeling of fullness and have fewer calories than fats or simple carbohydrates.
- Drink Plenty of Water — thirst is often confused with hunger. A glass of water before a meal reduces calorie intake.
- Plan Meals in Advance — when you are hungry, it is difficult to make rational decisions.
- Don't Forget Sleep — lack of sleep increases ghrelin (the hunger hormone) and decreases leptin (the satiety hormone).
- Use a Food Diary — even 2 weeks of tracking significantly increases awareness.
- Don't Be Afraid of Breaks — a "diet break" every 8–12 weeks helps restore hormonal balance.
❓ Frequently Asked Questions
It is recommended to stay in a deficit for no longer than 8–12 weeks without a break. After that, take a 1–2-week "diet break" (eat according to your TDEE) to restore hormonal balance and avoid metabolic adaptation.
No. A calorie deficit is the only way to lose weight. Even keto, IF or low-carb diets work only because they create a calorie deficit — there is no magic.
Possible reasons: you're calculating calories inaccurately, your body has adapted (NEAT decreased), water retention, hormonal changes. Review your calculations and consider a 1–2 week break.
💡 Practical Everyday Tips
📋 Track Progress
Use a diary or app. Weekly trends are more important than daily fluctuations. Regularly measure not only weight but also circumferences.
💧 Drink Enough Water
2–3 liters per day. Water aids digestion and metabolism and reduces false hunger.
😴 Sleep 7–9 Hours
Quality sleep is essential for hormonal balance, muscle recovery, and appetite control.
🏃 Move Every Day
Even 30 minutes of walking per day can significantly improve metabolism and mood.