Question 1

How many calories should I eat to lose weight?

Accepted Answer

To lose weight, eat fewer calories than you burn. A safe deficit is 10-20% of your TDEE, which leads to steady, sustainable weight loss. Use this calculator to find your TDEE, then select your deficit percentage. Going below 1,200 calories (women) or 1,500 calories (men) is not recommended without medical supervision.

Question 2

What is a safe calorie deficit?

Accepted Answer

A safe calorie deficit is typically 5-30% of your TDEE. A 20% deficit is most commonly recommended as it balances reasonable weight loss speed with sustainability. Deficits above 40% of TDEE increase the risk of muscle loss, nutrient deficiencies, hormonal disruption, and metabolic slowdown.

Question 3

How do I calculate my calorie deficit?

Accepted Answer

Step 1: Calculate your BMR using the Mifflin-St Jeor equation. Step 2: Multiply your BMR by your activity factor to get your TDEE (maintenance calories). Step 3: Subtract your desired deficit percentage (5-40% of TDEE) from your TDEE. The result is your daily calorie target for weight loss. This calculator handles all three steps automatically.

Question 4

Is a 1,000 calorie deficit safe?

Accepted Answer

A 40% TDEE deficit is considered extreme and can lead to rapid weight loss. While this can be safe for some individuals (particularly those with a lot of weight to lose), it often leads to muscle loss, fatigue, nutrient deficiencies, and is difficult to sustain. Most experts recommend starting with a 20% deficit and adjusting from there.

Question 5

How long does it take to lose 10 pounds with a calorie deficit?

Accepted Answer

The timeline depends on your TDEE and deficit percentage. At a 20% deficit most people lose about 0.5 kg (1 lb) per week, so 10 pounds takes roughly 10 weeks. A 30% deficit is faster (~7 weeks) and a 10% deficit is slower (~20 weeks). The actual rate varies based on starting weight, body composition, metabolic adaptation, and consistency.

Question 6

What happens if my calorie deficit is too large?

Accepted Answer

An excessively large calorie deficit can cause: muscle loss (your body breaks down muscle for energy), metabolic adaptation (your metabolism slows to conserve energy), hormonal disruption (reduced thyroid and reproductive hormones), nutrient deficiencies, increased hunger and cravings, fatigue and poor exercise performance, and a higher risk of binge eating. This is why sustainable, moderate deficits are recommended.

Question 7

Should I eat back exercise calories?

Accepted Answer

It depends on your goals. For weight loss, it's generally best to eat back only 50% of estimated exercise calories, since calorie burn estimates are often inflated by 30-50%. If you're very active and experiencing fatigue or excessive hunger, eating back more exercise calories may be appropriate. The activity level setting in this calculator already accounts for general exercise patterns in your TDEE.

Question 8

What is the difference between BMR and TDEE?

Accepted Answer

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest, just to keep you alive (breathing, heartbeat, cell repair). TDEE (Total Daily Energy Expenditure) is your total daily calorie burn including BMR plus all activity: walking, exercise, fidgeting, and digestion. TDEE = BMR × Activity Factor. Your calorie deficit should be subtracted from TDEE, not BMR.

Question 9

How accurate are calorie deficit calculators?

Accepted Answer

Calorie deficit calculators using the Mifflin-St Jeor equation are generally accurate within 10% for most people. However, individual variation exists due to genetics, hormones, medications, body composition, and metabolic adaptation. Use the calculator's estimate as a starting point, then monitor your weight for 2-4 weeks and adjust by 100-200 calories if needed. Actual results are more reliable than any formula.

Question 10

Can I lose weight without counting calories?

Accepted Answer

Yes, but a calorie deficit is still required — you just achieve it through behavior changes rather than tracking. Strategies include: eating more protein and fiber (keeps you full), reducing processed foods and sugary drinks, using smaller plates, eating slowly, and prioritizing whole foods. However, calorie tracking (even temporarily) helps build awareness of portion sizes and food energy density.

Question 11

What is calorie cycling and does it help?

Accepted Answer

Calorie cycling (or zigzag dieting) means varying your calorie intake day-to-day while aiming to maintain your weekly average deficit. For example, eating more on workout days and less on rest days. Research suggests it may help with adherence, reduce metabolic adaptation, and support better performance during exercise. Our 7-day plan distributes your calories with 2 higher days, 3 moderate days, and 2 lower days. If your target is near the safety floor, some days may be raised to the minimum, and the plan will note the adjusted average.

Question 12

Why am I not losing weight in a calorie deficit?

Accepted Answer

Common reasons include: underestimating food intake (measuring inaccurately), overestimating activity level, water retention masking fat loss (especially after starting exercise or during menstrual cycles), metabolic adaptation from prolonged dieting, or medical conditions affecting metabolism. Try recalculating your TDEE with your current weight, weighing food more precisely, or taking a 1-2 week diet break at maintenance calories.

Target	kg/wk	Timeline
2,529	0.1	~1y 7m
2,396	0.2	~9.7 months
2,130	0.5	~4.8 months
1,863	0.7	~3.2 months
1,597	1	~2.5 months

Formula	Best For	Requires
Mifflin-St Jeor	Most people (default)	Age, weight, height, gender
Katch-McArdle	Lean/athletic individuals	Weight, body fat %

Calorie Deficit Calculator

Deficit Comparison

Weight Loss Projection

Daily Macronutrients

7-Day Calorie Cycling Plan

What Your Deficit Looks Like

Understanding Your Numbers

What is a Calorie Deficit?

How This Calculator Works

BMR Formula Comparison

Common Mistakes to Avoid

Tips for a Successful Calorie Deficit

Frequently Asked Questions

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