What is a calorie deficit?
A calorie deficit means consuming less energy than your estimated daily energy expenditure. Over time, a sustained energy deficit can lead to weight loss, although real-world changes are not perfectly linear.
How the calorie deficit calculator works
The calculator estimates your maintenance calories and then reduces that estimate by the percentage you select. A moderate deficit is generally more practical than trying to reduce calories as aggressively as possible.
What different calorie deficits mean
The calculator applies the selected percentage to estimated maintenance calories. Larger deficits produce lower calorie targets, but a larger deficit is not automatically better.
| Selected deficit | Example from 2,500 kcal maintenance | General interpretation |
|---|---|---|
| 10% | 2,250 kcal/day | Small reduction; often easier to sustain |
| 15% | 2,125 kcal/day | Moderate reduction |
| 20% | 2,000 kcal/day | Common practical starting point |
| 25% | 1,875 kcal/day | Larger reduction; may be harder to sustain |
| 30% | 1,750 kcal/day | Aggressive reduction for many people |
Example deficit calculation
If estimated maintenance needs are 2,594 kcal/day and you select a 20% deficit, the calculator multiplies 2,594 by 0.80.
The resulting target is about 2,075 kcal/day, a reduction of roughly 519 kcal from estimated maintenance.
Choosing a calorie deficit
A moderate deficit is often more practical than choosing the largest available reduction. The goal is not simply to eat as little as possible.
Energy needs and weight change are estimates rather than perfectly predictable equations. Monitor your progress over time and adjust when appropriate.
When the calculated target is very low
Mealisa displays a warning when the calculated target falls below 1,200 kcal/day. This is a safety flag rather than a personalized minimum-calorie prescription.
Very low energy intakes can make it more difficult to meet nutrient needs. If a calculated target is unusually low or you have medical, nutritional, pregnancy, eating-disorder or other health considerations, seek individualized professional guidance rather than relying on a general calculator.
These calculators provide general estimates for healthy adults aged 18 and over. They are not medical advice and may not be appropriate during pregnancy, breastfeeding, for children, or when a medical condition affects energy or nutrition requirements.
Turn estimates into everyday nutrition.
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