Holistic Health
Intermittent Fasting Calculator
Enter your last meal time to see where you are in your fast: your current metabolic stage, time remaining, and when each stage of fasting begins.
If your last meal was yesterday, enter the time — we will calculate automatically.
The 16:8 Protocol — Why It Became the Default
The 16:8 protocol achieved widespread adoption largely because it maps naturally onto existing behavior for many people: if your last meal is at 8pm and you skip breakfast, eating lunch at noon gives you a 16-hour fast with no calendar disruption. For most people, the 8 sleeping hours cover more than half the fasting window.
The metabolic benefits — improved insulin sensitivity, increased fat oxidation, growth hormone elevation — begin meaningfully after the 12-hour mark, making 16:8 the minimum protocol for those seeking these effects. Shorter eating windows (18:6, 20:4) amplify the benefits and extend the autophagy window.