How many calories should I eat to lose 5 kg?

5 kg is the most-searched weight-loss goal on the internet, and for good reason: it's small enough to feel achievable, big enough to change how clothes fit, and roughly the difference between "I want to look better" and "people are asking what I'm doing". Here's the math.

The basic equation

A kilogram of body fat stores roughly 7,700 kilocalories of energy. So losing 5 kg of pure fat needs an accumulated deficit of about 38,500 kcal.

You don't lose 5 kg of pure fat, though — some of it will be glycogen (the carbs stored in your muscles, ~1.5–2 kg of weight shift in the first week alone), some water that travels with that glycogen, and a small amount of muscle tissue. The fat-only number is a useful upper bound; the actual scale weight comes off faster.

Picking your deficit size

The right deficit depends on how fast you want to lose, and how much pain you're willing to take. The trade-off is brutal: bigger deficit → faster scale movement → more muscle loss, more hunger, more metabolic adaptation. Three benchmarks:

• Conservative — 300 kcal/day deficit. About 5 kg in 18 weeks (4½ months). Easiest to sustain. Hunger is mild, training stays strong, sleep stays good. Recommended starting point for almost everyone.
• Moderate — 500 kcal/day deficit. About 5 kg in 11 weeks. Most people's realistic edge. Manageable hunger, occasional cravings, training capacity intact.
• Aggressive — 750 kcal/day deficit. About 5 kg in 7 weeks. Works briefly, often stalls by week 3. Hunger becomes intrusive, sleep degrades, training feels harder. Most people who try this end up regaining within 6 months.

You can plug your stats into our TDEE calculator to find your maintenance number, then subtract the deficit you want to run. Our fat-loss macro calculator does the math automatically.

Why aggressive cuts stall by week 3

The body actively defends its weight. As you eat less, four systems wake up to slow you down:

1. Metabolic adaptation — your TDEE drops by ~50 to 200 kcal beyond what the new body weight alone would predict. This isn't a metabolism "permanently destroyed" scare-story; it's temporary, recoverable, and roughly proportional to deficit size.
2. NEAT collapse — non-exercise activity (fidgeting, walking around, household chores) drops without you noticing. People in deeper deficits subconsciously sit more, walk less, and skip their evening kitchen-cleanup mostly out of energy conservation. Fitness watches catch this if you wear them.
3. Hunger hormones — leptin drops, ghrelin rises. By week 3 of an aggressive cut, the hunger isn't willpower failure; it's a coordinated biological response.
4. Cognitive bandwidth — willpower-driven food restriction is mentally expensive. Stress and decision fatigue compound quickly. By week 4 most aggressive dieters break the diet during a single high-cortisol week.

The literature is consistent on this: moderate, longer cuts beat aggressive, shorter ones on long-term outcomes. The aggressive cut group loses faster initially but regains more by month 12. The moderate cut group is still losing or holding at month 12.

The deficit-size sweet spot

For most adults, the practical number is 15–20% below maintenance. If your TDEE is 2,400 kcal, that's 1,920–2,040 kcal/day. If your TDEE is 1,800 kcal, that's 1,440–1,530 kcal/day.

That deficit gives you weekly fat loss of 0.4–0.7% of body weight. For a 70 kg adult, ~280–490 g/week. So the 5 kg target lands somewhere in 10 to 18 weeks depending on the size of the deficit and how aggressive you are about training during it.

Protect the muscle

Two non-negotiables turn weight loss into fat loss:

1. Eat 1.8–2.2 g protein per kg body weight per day. For a 70 kg adult that's 126–154 g. Hit it every day, not just on training days. Spread across all meals, not concentrated in dinner. We have a deeper article on protein for fat loss.

2. Lift heavy 2–3 times per week. Lifting in a deficit signals to the body that the muscle is "needed" and protects it from being broken down. Without lifting, you can easily lose 25–30% of your weight as muscle in a 12-week cut. With consistent strength training, that drops to ~10%.

What to expect, week by week

• Week 1. 1.5–3 kg lost. Mostly water and glycogen. Don't take this as your "rate" — it won't continue.
• Weeks 2–4. 0.4–0.7% of body weight per week. Hunger settles into a rhythm. Workouts feel similar to maintenance.
• Weeks 5–8. Possible plateau of 1–2 weeks. Don't cut harder. Sleep and stress more often than not are the culprits, not calorie precision.
• Weeks 9–12. Visible body composition change. Clothes fitting noticeably better. Strength might dip slightly. Training performance is the canary — if it's tanking, you're cutting too hard.
• End of cut. Don't snap back to your old calorie level. Reverse-diet: add 100 kcal/week back to TDEE over 3–4 weeks. Your metabolism needs the gradual return to avoid rebound.

The short version

To lose 5 kg sustainably: find your maintenance with our TDEE calculator, eat 15–20% below it, hit 1.8–2.2 g/kg of protein, lift 2–3 times a week. Plan for 10–18 weeks. Don't crash. Track waist circumference alongside the scale; both should be moving by week 4.

The 5 kg you lose this way doesn't come back next year. The 5 kg you lose on a 7-week crash usually does.