What is Calorie Compression?▼
When you follow intermittent fasting, your total daily calories and macros remain the same — they are just compressed into a shorter eating window. A person eating 2,000 calories across 6 meals becomes someone eating 2,000 calories across 2 meals within an 8-hour window. The same total, different distribution.
This calculator shows exactly how your daily targets translate into per-meal targets, making it easy to plan what to eat at each meal within your window.
How Eating Window Macro Distribution Works
Intermittent fasting compresses your eating into a defined window, but your nutritional requirements do not change. The same daily calories, protein, carbohydrates, and fat you need for your goals are simply distributed across fewer meals within the window.
Equal Macro Distribution
This calculator uses equal macro distribution across all meals in the window — each meal receives the same proportion of protein, carbs, and fat. The last meal receives any remainder from rounding to ensure your daily totals are exactly preserved. This approach simplifies meal planning because each meal is structurally identical.
Daily vs Per-Meal Comparison
The calculator displays both your daily totals and per-meal targets side by side. This comparison is useful for setting realistic expectations: if your daily protein target is 180g and you plan 2 meals, each meal needs 90g protein — which may require intentional food choices (chicken breast, cottage cheese, protein shake) to hit that target in a single sitting.
Choosing Your Protocol
16:8
The most flexible starting point. An 8-hour window fits 2–3 meals spaced 2–3 hours apart. Works for most schedules.
18:6
A 6-hour window fits 2 meals comfortably. Requires skipping breakfast and eating a later lunch and dinner.
20:4
A 4-hour window means 1–2 large meals. Per-meal calorie targets will be high — ensure your totals are achievable.
Protein Absorption Considerations
Current research suggests the body can utilize protein for muscle protein synthesis across meal sizes — there is no strict per-meal absorption limit as was previously thought. However, distributing protein across 2–3 meals provides more consistent amino acid availability throughout the eating window. If your window is short (4 hours or less) and protein needs are high, a protein supplement within the window can help reach your target without relying solely on whole foods.
Frequently Asked Questions
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