How Many Calories Should I Eat to Lose Weight?

"How many calories should I eat to lose weight?" is one of the most searched weight loss questions — and one with no universal answer, because the right number depends entirely on your individual energy expenditure. A 1,200-calorie target that produces a meaningful deficit for one person maintains weight or causes a deficit too large for another. This guide explains how to calculate the number that's right for you, how to adjust it based on results, and what constraints matter.

The Formula: TDEE Minus Your Target Deficit

Your daily calorie target for weight loss = your Total Daily Energy Expenditure (TDEE) minus your intended deficit.

TDEE is the total calories your body burns across a full day. To estimate it:

Step 1 — Calculate BMR (Mifflin-St Jeor equation):

• Women: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161
• Men: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5

Step 2 — Multiply by activity factor:

Activity level	Description	Multiplier
Sedentary	Desk job, minimal movement	× 1.2
Lightly active	Light exercise 1-3 days/week	× 1.375
Moderately active	Moderate exercise 3-5 days/week	× 1.55
Very active	Hard exercise 6-7 days/week	× 1.725

Step 3 — Subtract your deficit: For sustainable weight loss, a deficit of 400-600 calories/day is the standard starting range. This produces approximately 0.4-0.6kg of fat loss per week.

Worked Examples by Starting Weight

Profile	BMR	TDEE (lightly active)	Target intake (−500 cal)
Woman, 30y, 165cm, 70kg	1,419	1,951	~1,450 cal/day
Woman, 45y, 160cm, 85kg	1,511	2,078	~1,580 cal/day
Man, 35y, 178cm, 90kg	1,913	2,630	~2,130 cal/day
Man, 50y, 175cm, 100kg	1,930	2,654	~2,150 cal/day
Woman, 28y, 170cm, 65kg	1,444	1,985	~1,485 cal/day

The range across these examples — 1,450 to 2,150 calories — illustrates why a single fixed target is meaningless. Two people can have the same goal and the right calorie target for weight loss can differ by 700 calories.

Minimum Calorie Floors

A deficit can be too large. Below certain intake levels, the risks of lean muscle loss, micronutrient deficiency, and diet-induced fatigue outweigh the benefit of faster fat loss.

Practical minimum targets for weight loss:

• Women: 1,200-1,400 kcal/day as an absolute minimum; 1,400+ is more sustainable
• Men: 1,500-1,700 kcal/day as an absolute minimum; 1,600+ is more sustainable

These floors are not magic thresholds — they reflect the point at which it becomes practically difficult to meet protein, fibre, and micronutrient targets while remaining in significant deficit. If your calculated target falls below these floors, do not simply eat at the floor and assume the implied deficit is correct. Instead:

1. Verify your TDEE estimate is accurate (activity multipliers are frequently overestimated)
2. Consider a smaller deficit (300-400 cal/day) rather than an aggressive one
3. Add structured activity to increase TDEE rather than further reducing intake

Very low calorie diets (under 800 kcal/day) exist as medically supervised interventions for specific cases — they are not appropriate for unsupervised weight loss and reliably cause significant lean mass loss alongside fat loss.

Why Your TDEE Changes as You Lose Weight

TDEE is not fixed. It decreases as body weight decreases, for two reasons:

Lower body mass burns fewer calories. A lighter body requires less energy to move and maintain. A person who loses 10kg has a BMR approximately 100-150 kcal/day lower than when they started. If they maintain the same calorie intake throughout, the actual deficit shrinks over time and weight loss slows — even if they are doing everything right.

Metabolic adaptation. Sustained calorie restriction causes the body to reduce TDEE beyond what body mass reduction alone explains. NEAT decreases (unconscious movement becomes less frequent), and metabolic efficiency increases slightly. This effect is real but typically modest — 5-10% of TDEE — over the timescales of a standard weight loss programme.

Practical implication: Recalculate your calorie target every 5-7kg of weight lost, or whenever progress has stalled for 4+ weeks despite consistent tracking. The target that was right at 85kg may need to drop by 100-150 calories by the time you reach 78kg.

How to Set Your Starting Target

A reliable starting approach:

1. Calculate TDEE using the formula above
2. Subtract 500 calories as your starting daily target
3. Check against the minimum floor — if the result is below 1,200 (women) or 1,500 (men), use a smaller deficit or reconsider the activity multiplier
4. Set a protein target of 1.6-2.0g per kg of current bodyweight — this is non-negotiable at any calorie level; adequate protein preserves muscle mass during the deficit
5. Track for 3-4 weeks with consistent accuracy before drawing conclusions about whether the target is right

How to Know If Your Target Is Right

The test is simple: after 3-4 weeks of accurate tracking at your target, is your average weekly body weight declining?

• Weight declining at ~0.3-0.7kg/week: Target is correct. Maintain it, and recalculate every 5-7kg lost.
• Weight holding or rising: Either the target is too high, or tracking accuracy has drifted. The most common cause is underestimation of calories eaten — portions of high-calorie-density foods (oils, nut butters, nuts, cheese) are systematically underestimated without weighing. Tighten tracking accuracy before dropping the calorie target.
• Weight declining faster than 0.7-0.8kg/week consistently: Deficit may be too aggressive. Consider raising intake by 100-200 calories to protect lean mass, particularly if strength or energy levels are declining.

Use 4-week weight averages, not day-to-day readings. Day-to-day scale fluctuations of 1-2kg are normal and reflect water, glycogen, and bowel contents — not fat change. A single week of no movement is not evidence the target is wrong.

Adjusting Your Target Over Time

When progress stalls for 4+ weeks at consistent tracking accuracy, the appropriate adjustment is small and incremental:

• Reduce daily intake by 100-150 calories (not 300-500)
• Or add 20-30 minutes of walking per day to increase TDEE rather than reduce intake further
• Maintain the adjustment for 3-4 weeks before evaluating again

Large calorie cuts in response to stalls are counterproductive — they increase muscle loss risk, worsen adherence, and often create a rebound effect when the restriction becomes unsustainable. The compounding effect of small, sustained adjustments is more effective than dramatic short-term cuts.

Common Mistakes

Using a generic target without calculating individual TDEE. "Eat 1,200 calories to lose weight" is advice calibrated to a specific body size and activity level. Applied universally, it under-restricts heavier or more active people and over-restricts lighter or less active people. Calculate your number.

Overestimating the activity multiplier. Most people in desk jobs with 3-4 gym sessions per week are lightly active (×1.375), not moderately active (×1.55). The difference is approximately 250-300 calories/day — enough to turn a planned deficit into maintenance. When in doubt, start with the lower multiplier and adjust upward if weight loss is faster than expected.

Treating the formula as precise. BMR formulas have a ±10-15% error range for individuals. Use the result as a starting estimate, not a precise measurement. Empirical calibration — tracking intake and weight change over 3-4 weeks — produces a more accurate individual TDEE than any formula.

Dropping calories when tracking accuracy is the problem. If weight is not declining at a calorie target that should produce a deficit, the first diagnostic is tracking accuracy, not the target itself. See our troubleshooting guide for a systematic approach.

The Protein Constraint

Your calorie target should be set to accommodate adequate protein intake. At 1.6-2.0g protein per kg of bodyweight, protein alone accounts for a significant fraction of total calories:

• 70kg person at 1.8g/kg = 126g protein/day = 504 calories from protein alone
• 85kg person at 1.8g/kg = 153g protein/day = 612 calories from protein alone

At very low calorie targets (below 1,200-1,400), hitting the protein target leaves minimal calories for carbohydrates and fats — making the diet practically unworkable and nutritionally incomplete. This is one of the structural reasons aggressive calorie restriction is counterproductive: it forces a trade-off between total intake and protein adequacy that undermines both fat loss quality and dietary adherence. See our protein requirements guide for the full evidence base.

Summary

• Your daily calorie target = TDEE − deficit; there is no universal number — the correct target depends entirely on your individual energy expenditure
• Calculate TDEE using the Mifflin-St Jeor formula × activity multiplier, then subtract 400-600 calories for a sustainable deficit
• Minimum practical floors: ~1,200-1,400 for women, ~1,500-1,700 for men — below these, protein and micronutrient targets become difficult to meet
• Recalculate every 5-7kg lost — TDEE decreases with bodyweight, and the deficit narrows if the target isn't updated
• When progress stalls, tighten tracking accuracy before dropping calories — underestimation of high-calorie-density foods is the most common cause of apparent deficit failure
• Adjust in 100-150 calorie increments, not large cuts — small sustained adjustments outperform dramatic restrictions

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Related Reading

• How to Count Macros for Weight Loss: A Practical Guide
• What Is a Calorie Deficit and How Does It Work?
• Calorie Deficit for Beginners: How to Calculate Yours and Actually Maintain It
• How Much Protein Do You Need to Lose Weight? The Evidence-Based Answer
• Why Am I Not Losing Weight on a Calorie Deficit? A Troubleshooting Guide

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