CALCULATOR

Eating Window Calculator

Your 16:8 or other window mapped out, with a check on whether your protein target actually fits inside it.

Your eating window

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Window–

Fasting period–

Daily protein target–

Meals that fit–

Protein per meal needed–

Training falls–

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Planning a time-restricted eating window

Time-restricted eating means confining food to a set number of hours daily. The most common and most studied pattern is 16:8, an eight hour window.

The practical constraint that gets least attention is protein. Muscle protein synthesis is stimulated per feeding rather than per day, so a shorter window means fewer stimulation events, and hitting a target of 140 g becomes considerably harder in four hours than in eight.

This calculator shows how many meals realistically fit your window and what each would need to contain. When the per-meal figure exceeds about 50 g, the plan is usually unrealistic and a longer window is the better answer.

Frequently asked questions

What is a good eating window?

Eight hours suits most people and has the most research behind it. Shorter windows make protein targets harder.

Should I train fasted?

Fine for most people. Getting protein in reasonably soon afterwards matters more than whether you ate before.

Does the window need to be the same every day?

Consistency helps circadian regulation and adherence, though occasional variation is not a problem.

Is time-restricted eating better for fat loss?

At matched calories, trials generally find similar results to continuous restriction. It helps if it makes you eat less.

Sources

Lowe DA et al. Effects of Time-Restricted Eating on Weight Loss and Other Metabolic Parameters. JAMA Internal Medicine, 2020.
Moore DR et al. Ingested protein dose response of muscle and albumin protein synthesis. American Journal of Clinical Nutrition, 2009.
Tinsley GM, La Bounty PM. Effects of intermittent fasting on body composition and clinical health markers. Nutrition Reviews, 2015.
National Institutes of Health, Office of Dietary Supplements. Nutrient fact sheets. ods.od.nih.gov
NHS. Nutrition and health guidance. nhs.uk
US Departments of Agriculture and Health and Human Services. Dietary Guidelines for Americans, 2025-2030. dietaryguidelines.gov

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General information, not medical advice. Consult a qualified professional before changing your diet, especially with a medical condition.