Find your exact daily calorie target to lose weight at a healthy pace — and see when you'll reach your goal.
Units
Sex
Your Weight Loss Plan
—kcal/day
Your Daily Calorie Goal
— kcal deficit from your TDEE of — kcal
Weekly Loss
—
kg/week
Weeks to Goal
—
weeks
Goal Date
—
estimated
Suggested Daily Macros
Protein
—
g/day
Carbs
—
g/day
Fat
—
g/day
High protein intake during a deficit helps preserve muscle mass. The macro split above uses ~35% protein, 35% carbs, 30% fat.
What Is a Calorie Deficit?
A calorie deficit occurs when you consume fewer calories than your body burns. It's the only scientifically proven mechanism for fat loss — regardless of which diet you follow (Hall et al., 2012).
Your body needs energy to function. When you don't provide enough through food, it taps into stored energy (primarily body fat) to make up the difference. Over time, this leads to weight loss.
The truth about diets: Every diet that works — keto, intermittent fasting, low-fat, paleo — works because it creates a calorie deficit. The diet is just the vehicle; the deficit is the engine.
The 7,700 Rule
One kilogram of body fat stores approximately 7,700 kcal of energy (about 3,500 kcal per pound). This gives us a practical framework:
500 kcal/day deficit = ~0.5 kg/week loss (3,500 kcal/week)
1,000 kcal/day deficit = ~1 kg/week loss (7,000 kcal/week)
Reality check: you won't lose only fat. Water weight fluctuates daily (sometimes by 1–2 kg), and some muscle loss is normal during a deficit — especially without adequate protein and resistance training.
Don't panic: In the first 1–2 weeks of a deficit, you may lose 1–3 kg rapidly — that's mostly water and glycogen, not fat. Don't be discouraged when the pace slows down. That's actually when real fat loss begins.
Safe Deficit Guidelines
Not all deficits are created equal. The right size depends on your starting point and lifestyle:
Mild — 250 kcal/day (0.25 kg/week): Easiest to sustain, minimal hunger. Ideal for those close to goal weight or with an active lifestyle.
Moderate — 500 kcal/day (0.5 kg/week): The sweet spot for most people. Noticeable results without extreme restriction.
Aggressive — 750–1,000 kcal/day (0.75–1 kg/week): Only recommended if significantly overweight. Higher risk of muscle loss and fatigue.
Minimum safe intake: Never go below 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision.
The larger the deficit, the higher the risk of muscle loss, nutrient deficiencies, and metabolic adaptation — where your body reduces its energy expenditure to compensate.
Why Extreme Deficits Backfire
Going too aggressive with your deficit triggers a cascade of biological defence mechanisms:
Metabolic adaptation: Your body reduces energy expenditure by 15–20% beyond what weight loss alone would predict (Rosenbaum & Leibel, 2010).
Muscle loss: Without adequate protein and resistance training, up to 25% of weight lost can be lean muscle — making you weaker and lowering your BMR further.
Hormonal disruption: Leptin (satiety hormone) drops, ghrelin (hunger hormone) rises, and cortisol (stress hormone) increases — a perfect storm for cravings.
Rebound effect: 80% of people who lose weight regain it within 2 years (Wing & Phelan, 2005). Extreme deficits make this even more likely.
Historical context: The Minnesota Starvation Experiment (1944) showed that men on 1,570 kcal/day developed obsessive food thoughts, depression, and a 40% drop in BMR. Sustainability matters more than speed.
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MacroLog sets your calorie target automatically and tracks every meal via AI photo recognition, voice, or barcode scan.