Question 1

How many calories per day to lose 1 kg per week?

Accepted Answer

To lose 1 kg of fat per week, the cumulative deficit required is ~7,700 kcal/week, or ~1,100 kcal/day. That's an aggressive pace, recommended only for people with significant excess weight (BMI > 30) and for a limited time (4–6 weeks max). For most, aiming for 0.5 kg/week (a 500 kcal/day deficit) is more sustainable and better preserves muscle mass (Helms 2014)[3].

Question 2

How many calories to lose 5 kg?

Accepted Answer

Losing 5 kg of fat requires a cumulative deficit of ~38,500 kcal. At a 500 kcal/day deficit (moderate pace), it takes ~11 weeks (2.5 months). At 750 kcal/day, ~7 weeks. For an 80 kg sedentary man with a TDEE of 2,400 kcal, the daily target drops to 1,900 kcal at moderate pace and 1,650 kcal at fast pace.

Question 3

How many calories to lose 10 kg?

Accepted Answer

10 kg of fat = ~77,000 kcal of cumulative deficit. At moderate pace (-500 kcal/day, -0.5 kg/week), expect ~22 weeks (5 months). At slow pace (-250 kcal/day, -0.25 kg/week), ~44 weeks (10 months). Important: recompute TDEE every 5 kg lost, because expenditure drops with weight and metabolic adaptation.

Question 4

How many calories to lose 20 kg?

Accepted Answer

20 kg = ~154,000 cumulative kcal. On a constant moderate pace, theoretically ~44 weeks, but reality is different: metabolic adaptation and the drop in TDEE stretch the timeline to 10–14 months in practice. Recommended strategy: segment into 8–10 week deficit blocks + 2 weeks of diet break at TDEE to preserve metabolism and adherence (Byrne et al., 2018)[5].

Question 5

How many calories per day for a woman who wants to lose weight?

Accepted Answer

Needs are computed from personal TDEE, not from one-size-fits-all numbers. For a 65 kg sedentary woman, typical TDEE is ~1,800 kcal/day; a moderate 20 % deficit gives 1,440 kcal/day. Safety floor: never go below 1,200 kcal/day. If your computed target falls below that, raise expenditure (cardio, walking) instead of dropping intake further.

Question 6

How many calories per day for a man who wants to lose weight?

Accepted Answer

For an 80 kg sedentary man, typical TDEE is ~2,400 kcal/day; a moderate 20 % deficit gives 1,920 kcal/day. Safety floor: 1,500 kcal/day. For active men (TDEE ≥ 2,800 kcal), the deficit can look generous in absolute terms while staying moderate as a percentage — what matters is the ratio, not the raw number.

Question 7

Why 7,700 kcal per 1 kg of fat?

Accepted Answer

1 kg of adipose tissue contains roughly 85 to 87 % pure lipids (the rest is water, protein and structure). 1 g of lipid releases 9 kcal. The calculation therefore gives between 7,650 kcal (1,000 g × 85 % × 9) and 7,830 kcal (1,000 g × 87 % × 9): it is this range that gets summarized by the round figure of 7,700 kcal, inherited from Wishnofsky (1958). The rule remains useful as a first approximation, but it overestimates long-term loss: dynamic models (Hall 2011[1], Hall 2008[2]) show that the deficit required per kilo is not constant and rises as weight comes down.

Question 8

Should I drop below 1,200 kcal to lose weight fast?

Accepted Answer

No, never on your own. Below 1,200 kcal (woman) or 1,500 kcal (man), three risks appear: (1) micronutrient deficiencies (iron, B12, calcium), (2) accelerated muscle loss, (3) persistent metabolic slowdown. If your computed target falls below this floor, your TDEE is very low — raise expenditure (walk 8,000–10,000 steps/day) instead of cutting intake further.

Question 9

Why am I no longer losing weight even though I eat little?

Accepted Answer

Five typical causes. (1) By far the most common one is underestimating actual intake: Lichtman et al. (1992)[4] measured a gap of about 47 % between reported and actual intake in people who were not losing weight — on a small sample selected for that profile, but with energy expenditure perfectly in line with predictions, which rules out the “slow metabolism” explanation. (2) Metabolic adaptation: resting expenditure drops beyond what weight loss alone would predict, all the more so as the deficit is deepened and prolonged. (3) Missed TDEE recompute: if you were at 80 kg and are now at 75 kg, your TDEE has dropped[1][6]. (4) Water retention (stress, cycle, sodium). (5) Muscle loss if protein is insufficient. Solution: weigh every food for 7 days straight, then recompute.

Question 10

How many calories below my needs?

Accepted Answer

10–25 % of TDEE depending on pace. Slow (-10–15 %, i.e. -250 kcal for a TDEE of 2,000): for advanced users or people close to their target weight. Moderate (-20 %, i.e. -500 kcal): the recommended standard, which suits the vast majority of situations. Beyond 25 % of TDEE, a deficit calls for medical supervision, whatever your starting BMI: the risks of deficiencies, muscle loss and hormonal disruption rise sharply.

Question 11

Is it better to count calories or macros?

Accepted Answer

Both. Calories determine whether you lose weight. Macros (especially protein) determine WHAT you lose: muscle or fat. Without protein tracking (1.8–2.2 g/kg) or resistance training, a significant share of the weight you lose comes from muscle — up to 30 to 40 % of the weight lost in the worst cases. With high protein and strength training, that share drops sharply[3]. The quartet to track: total kcal, protein, fat (min 0.8 g/kg), carbs (the rest).

Question 12

How many calories per day to avoid regaining weight after a diet?

Accepted Answer

Your TDEE recomputed at your new weight — not the TDEE from before the diet. Example: if you went from 80 to 70 kg and were eating 1,800 kcal in a deficit, your new maintenance is ~2,100 kcal (vs 2,400 before). Reverse-diet strategy: gradually raise intake by +100 kcal/week over 4–6 weeks once the goal is reached, to stabilize without rebound. Jumping straight back to your old maintenance creates a real surplus, and weight climbs back fast — first as water and glycogen, then as fat if the surplus sticks around.

Profile	TDEE	Target	Pace
Male 60 kg, sedentary175 cm · 30 yrs	1,859	1,487	−0.34 kg/wks
Male 80 kg, sedentary175 cm · 30 yrs	2,099	1,679	−0.38 kg/wks
Male 80 kg, sport 3-5×/week175 cm · 30 yrs	2,711	2,168	−0.49 kg/wks
Female 60 kg, sedentary165 cm · 30 yrs	1,584	1,267	−0.29 kg/wks
Female 65 kg, sedentary165 cm · 30 yrs	1,644	1,315	−0.30 kg/wks
Female 70 kg, sport 3-5×/week165 cm · 30 yrs	2,201	1,761	−0.40 kg/wks

Goal	Cumulative deficit	Slow pace	Moderate pace	Fast pace
1 kg	7,700 kcal	~4 wks	~2 wks	~1.5 wks
2 kg	15,400 kcal	~9 wks	~4 wks	~3 wks
5 kg	38,500 kcal	~22 wks	~11 wks	~7 wks
10 kg	77,000 kcal	~44 wks	~22 wks	~15 wks
20 kg	154,000 kcal	~88 wks	~44 wks	~29 wks

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The scientific formula: 7,700 kcal = 1 kg of fat

How many calories by profile

How many calories to lose 1, 5, 10, 20 kg?

5 traps that derail 80% of diets

Underestimating intake

Not recalculating TDEE after losing 5 kg

Going below 1,200 kcal (women) or 1,500 (men)

Neglecting protein

Bouncing back too fast after reaching the goal

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