Short answer
For most adults, 1,200 calories is too low. For a 75 kg woman with a TDEE of 1,900–2,100, it creates a 700–900 calorie daily deficit — well beyond the 300–500 range that evidence supports for sustainable fat loss with muscle retention.
1,200 is the most quoted number in dieting and one of the least justified. It is not a floor derived from physiology — it is a round number that stuck.
Why it is usually too aggressive
Take a 75 kg woman with a total daily energy expenditure of 1,900–2,100 calories. Eating 1,200 puts her in a 700 to 900 calorie daily deficit. The evidence-supported range for fat loss while retaining muscle is 300 to 500.
A deficit that size is not twice as effective. It is harder to hold, costs more lean mass, and the fast early drop is substantially water.
| Deficit per day | Roughly | Realistic outcome |
|---|---|---|
| 300–500 cal | 0.5–1 lb / week | Sustainable, muscle largely retained |
| 700–900 cal | 1.5–2 lb / week | Hard to sustain, more lean loss, high rebound risk |
When 1,200 is actually reasonable
It is not universally wrong. A small, sedentary woman — say 150 cm and 45 kg with a desk job — might have a TDEE around 1,400–1,500. For her, 1,200 is a moderate 200–300 calorie deficit and perfectly sensible.
The problem is that the number gets applied to everyone regardless of size and activity, which is how a moderate deficit for one person becomes a severe one for another.
The nutrition problem
Separately from the deficit size: at 1,200 calories it becomes genuinely difficult to hit protein, fibre, and micronutrient requirements. The lower the intake, the less room for error, and nutrient shortfall is a real risk rather than a theoretical one.
A better approach
- Estimate your maintenance, or simply log what you currently eat for a week without changing anything.
- Subtract 300–500. That is your target.
- Prioritise protein within it — it protects muscle and does the most for hunger.
- Track weight as a weekly average and adjust after three weeks, not three days.
