Why energy balance decides everything
Every diet that works — keto, low-fat, fasting, or smaller portions of ghar-ka-khana — works one way: you eat fewer calories than you burn. One kilogram of body fat stores roughly 7,700 kcal, so a daily deficit of 500 kcal removes about 3,500 kcal a week, or close to half a kilo. The diet is the delivery vehicle; the deficit is the engine.
A 70 kg person at 1.75 m has a BMI of 22.9 (70 divided by 1.75 squared) — squarely healthy — yet may still want to lose 5 kg of desk-job fat. The math below turns that vague wish into an exact plan with a predictable weekly pace.
- 1 kg of fat stores about 7,700 kcal
- A 500 kcal daily deficit predicts ~0.5 kg lost per week
- Small deficits held for months beat crash diets abandoned in weeks
Find your maintenance calories first
Your Total Daily Energy Expenditure (TDEE) is basal metabolism plus all movement. The Mifflin-St Jeor equation estimates the basal part: for men, 10 × weight in kg + 6.25 × height in cm − 5 × age + 5; for women it ends − 161. A 30-year-old man at 80 kg and 180 cm burns 800 + 1,125 − 150 + 5 = 1,780 kcal at complete rest.
Multiply by activity: 1.2 sedentary, 1.375 light, 1.55 moderate (3–5 workouts a week), 1.725 hard daily training. Our man at moderate activity maintains 1,780 × 1.55 = roughly 2,760 kcal. A 30-year-old woman at 65 kg and 165 cm has a basal rate near 1,370 kcal, so light activity puts her maintenance at about 1,370 × 1.375 = 1,884 kcal.
- 80 kg man, moderate activity: maintenance near 2,760 kcal
- 65 kg woman, light activity: maintenance near 1,880 kcal
- Be honest — desk jobs count as sedentary even with gym visits
Pick a deficit that gives 0.5 kg a week
Subtract 400–500 kcal from maintenance: our 80 kg man targets ~2,260 kcal, predicting 12 × 0.45 = about 5.4 kg over 12 weeks. The 65 kg woman targets ~1,380–1,480 kcal for 4–5 kg over the same quarter. Fast enough to stay motivated, slow enough to keep muscle and sleep intact.
Never eat below your basal rate for long — roughly 1,500 kcal for most men, 1,200 for most women — since 1,000 kcal cuts mostly drain water, glycogen, and muscle. If you have thyroid issues, diabetes, or a history of disordered eating, talk the plan through with your doctor first.
- 400–500 kcal deficit is the sweet spot for most adults
- Expect 0.25–0.5 kg a week; two-week plateaus are normal
- Flat for 3+ weeks? Cut 150–200 kcal or add 2,000 daily steps
What a 1,900-calorie day actually looks like
Breakfast: vegetable poha with peanuts plus milk, ~450 kcal and 18 g protein. Lunch: two rotis, dal, sabzi, curd, and salad — ~650 kcal, 25 g protein. Evening: buttermilk and roasted chana, ~150 kcal. Dinner: chicken or paneer with vegetables and one roti, ~500 kcal, 35 g protein. Total: ~1,750–1,900 kcal with 90–100 g protein, nothing exotic.
Two levers do the heavy lifting: protein near 1.6 g per kg (110–130 g for a 70–80 kg adult) to protect muscle and blunt hunger, and 7,000–9,000 daily steps worth ~250–350 kcal. Pre-log restaurant meals — one butter naan with dal makhani can quietly cross 900 kcal.
- Anchor meals with 25–40 g protein for fullness
- Steps cover nearly half the deficit without a workout
- Liquid calories — juices, shakes, sugary chai — sink budgets silently
Track the trend, not the daily noise
Weight swings a kilo overnight from salty food, hard workouts, or hormonal cycles — none of it fat. Weigh first thing in the morning 3–4 times a week and judge the 7-day average against the prior week. Falling 0.3–0.5 kg weekly means the plan works; flat for three weeks means targets are stale.
Log food honestly for one month with a kitchen scale: most people discover their tablespoon of peanut butter is really three (95 vs ~300 kcal). Recalculate maintenance every 4–5 kg lost, since lighter bodies burn less — our 2,760 kcal man may maintain near 2,600 kcal at 75 kg.
- Compare weekly averages, never yesterday vs today
- One honest logging month teaches portion sizes permanently
- Recalculate targets every 4–5 kg lost
5 mistakes that stall fat loss
Weekend amnesia leads: a clean 500 kcal deficit Monday–Friday (2,500 banked) erased by a 3,000 kcal surplus Saturday. Next comes under-counting oil, nuts, and nibbles — two handfuls of mixture plus a second ladle of tadka add 300+ unlogged kcal. Third, drinking the deficit through lassis, mocktails, and frappes.
Fourth, cardio-only dieting with little protein, which burns muscle alongside fat and lowers maintenance. Fifth, switching plans every ten days so nothing survives to show its three-week trend. Run one sensible plan six honest weeks before judging it.
- Weekends count — one binge erases five deficit days
- Measure oil and dry fruits; both double too easily
- Lift twice weekly with high protein to lose fat, not muscle
Weight-loss questions everyone asks
Must you quit rice or carbs? No — measured rice fits any deficit, and matched-calorie trials lose similar fat at any carb level. Keep foods you love in smaller amounts; the plan you enjoy for a year beats the perfect one you quit in February. Spot reduction is a myth — crunches do not melt belly fat — but waistlines shrink reliably as total fat falls.
Take a weekly cheat meal, not a 4,000 kcal cheat day that cancels the week. Stop dieting near a waist under half your height with stable strength and energy (roughly BMI 20–25 for most adults), then hold by eating at TDEE with the same steps and protein.
- No food group must go — totals decide fat loss
- One cheat meal helps; a cheat day erases the week
- Maintain at TDEE, keep protein and steps, weigh monthly