Counting Calories: Food Energy, Tracking & Burn Rates

Key Takeaways

Macro energy: protein 4, carbs 4, fat 9, alcohol 7 kcal/g — fat is 2.25× denser than protein

Fat math: ~7,700 kcal ≈ 1kg body fat; 500 kcal/day deficit → ~0.5kg/week

Tracking gap: labels allow ±20% error; untracked oil/sauces/drinks hide 300-600 kcal/day

Exercise burn: 70kg person — running 10km/h ~600 kcal/hr; walking ~240; swimming ~500

Core answer: calories come from three macronutrients — carbs 4 kcal/g, protein 4 kcal/g, fat 9 kcal/g. A bowl of rice (200g cooked) is ~230 kcal; a full-sugar bubble tea is 400-600 kcal; 30 minutes of jogging burns only ~300 kcal. Fat loss is 80% diet, 20% exercise.

Calories and the macronutrients

Nutrient	Energy density	Main sources
Carbohydrate	4 kcal/g	rice, noodles, sugar
Protein	4 kcal/g	meat, eggs, dairy, soy
Fat	9 kcal/g	oils, nuts, fatty meat
Alcohol	7 kcal/g	drinks

Units: 1 kilocalorie (kcal, the "Calorie" on labels) = 4.184 kilojoules (kJ). Everyday "calories" actually means kcal.

Common foods

Food	Serving	Calories
Cooked rice	1 bowl, 200g	230 kcal
Steamed bun	1, 100g	223 kcal
Egg	1	70 kcal
Chicken breast	100g	133 kcal
Pork belly	100g	395 kcal
Bubble tea, full sugar	500ml	400-600 kcal
Fried chicken (1 piece)	120g	330 kcal
Apple	1, 200g	100 kcal
Potato chips	small bag, 50g	270 kcal
Cola	330ml	140 kcal

Reading nutrition labels

Find the "energy" row: it's in kJ — divide by 4.2 for familiar kcal
Check "per 100g" vs "per serving": chips labeled 2200kJ/100g mean the whole 150g bag = 786 kcal
NRV%: the share of a 2000 kcal/day reference diet

Exercise burn table

30 minutes for a 70kg adult (approximate):

Activity	Burn
Brisk walking	150 kcal
Jogging 8km/h	300 kcal
Swimming	250 kcal
Jump rope	330 kcal
Leisure cycling	180 kcal
Strength training	150 kcal

In food terms: one full-sugar bubble tea ≈ 45-60 minutes of jogging.

The fat-loss deficit

Safe deficit: 300-500 kcal/day → 0.3-0.5kg per week
1kg of body fat ≈ 7,700 kcal: a 500 kcal daily deficit loses ~1kg in 15 days
Never eat below your BMR (~1,200 women, ~1,500 men) — or metabolism drops and muscle burns off

Common mistakes

"More sweat = more burn": sweat is cooling, not fat loss. Hot-yoga weight loss is water — it returns with the next drink.
"Zero-calorie drinks are free": sweeteners are near-zero calories, but some studies suggest they feed the sweet tooth. Better than sugary drinks — but water is always best.
"Fruit can't make you fat": fruit contains fructose; excess still converts to fat. Keep to 200-350g/day (1-2 fist-sized); juice without fiber is essentially sugar water.

Frequently Asked Questions

How are food calories calculated?

Atwater factors: protein 4 kcal/g, carbohydrates 4 kcal/g, fat 9 kcal/g, alcohol 7 kcal/g, fiber ~2 kcal/g. A meal with 30g protein + 60g carbs + 20g fat = 120 + 240 + 180 = 540 kcal. Fat's 9 kcal/g is why a tablespoon of oil (13.5g = 120 kcal) quietly equals a whole bowl of rice.

How do I read a nutrition label correctly?

Three checks: (1) serving size vs your portion — a "130 kcal serving" bag containing 2.5 servings is 325 kcal; (2) per-100g column for comparing products; (3) sneaky splits — "sugar" appearing as syrup, dextrose, maltose separately. Labels are legally allowed ±20% error in many jurisdictions, so treat totals as estimates, not gospel.

How much deficit do I need to lose 1kg?

~7,700 kcal per kg of body fat. A 500 kcal/day deficit → 3,500/week → ~0.45kg/week. Expect faster scale movement in week 1-2 (water and glycogen), then the true fat-loss rate. Deficits beyond 1,000 kcal/day strip muscle and crash adherence — 0.5-1% of body weight per week is the sustainable ceiling.

Why does my calorie count not match my results?

The four usual leaks: (1) cooking oil — a "glug" is 10-20g = 90-180 invisible kcal; (2) liquids — lattes, juice, bubble tea (200-600 kcal); (3) weekend amnesia — two 3,500-kcal days erase a 5-day deficit; (4) portion optimism — "a handful" of nuts is often 40g = 240 kcal. Weigh food for 2 weeks to recalibrate your eye; the gap usually closes immediately.

How many calories does exercise burn?

Per hour at 70kg body weight: running 10km/h ~600, running 8km/h ~480, cycling moderate ~500, swimming ~500, brisk walking ~240, strength training ~300-400, yoga ~200. Scale linearly with weight (90kg ×1.29). Machines overestimate 20-50% — and a single bubble tea (500 kcal) cancels a 45-minute run, which is why fat loss is won in the kitchen.

Is a calorie always a calorie?

Thermodynamically yes; practically no. Protein costs 20-30% of its energy to digest (vs 5-10% carbs, 0-3% fat) and satiates far more; 300 kcal of chicken breast keeps you full hours longer than 300 kcal of soda. Ultra-processed foods are eaten ~500 kcal/day more in controlled trials. Count calories for the budget, choose food quality for the adherence.