⏱ Intermittent Fasting Guide & Timer

Compare protocols, find your eating window, and track what's happening inside your body.

📑 Protocol Comparison

16:8

16h fast / 8h eating

Most popular. Skip breakfast, eat noon–8pm. Sustainable for most people long term.

Beginner Friendly

18:6

18h fast / 6h eating

Intermediate step up. Deeper ketosis. Eat within a 6-hour window, e.g. 1pm–7pm.

Intermediate

20:4

20h fast / 4h eating

The "Warrior Diet". 1–2 meals in a 4-hour window. Significant fat adaptation.

Advanced

OMAD

23h fast / 1h eating

One Meal A Day. Extreme calorie restriction window. Requires careful nutrient planning.

Expert

5:2

2 days/week very low cal

Eat normally 5 days. Restrict to 500–600 cal on 2 non-consecutive days. No daily timing needed.

Intermediate

🕐 Your Eating Window

Selected Protocol

Last Meal Time (yesterday or today)

🧠 What's Happening Inside You

12h

Glucose Depleted — Fat Burning Begins

Liver glycogen stores are used up. Insulin levels drop significantly. Your body shifts from burning glucose to burning stored fat for energy.

16h

Ketosis Enters — Increased Fat Oxidation

The liver begins producing ketone bodies from fatty acids. Mental clarity often improves. This is the target zone for most 16:8 practitioners.

18h

Autophagy Ramps Up

Cellular "self-cleaning" process (autophagy) significantly increases. Damaged proteins and organelles are recycled. Linked to longevity and reduced inflammation.

24h

Deep Autophagy + HGH Surge

Human Growth Hormone levels can increase by 1,300–2,000%. Autophagy reaches peak levels. AMPK (cellular energy sensor) fully activated — promotes fat burning.

48h

Immune System Reset Begins

Stem cells may begin replenishing immune cells. Insulin sensitivity significantly improved. Extended fasts beyond 24h should be done under medical supervision.

Intermittent Fasting Basics

Intermittent fasting (IF) is an eating pattern that cycles between periods of fasting and eating. Unlike diets, it doesn't specify what to eat — only when. The metabolic benefits come from the low-insulin state achieved during the fasting window.

Breaking your fast: Water, black coffee, and plain tea (zero calories) do not break a fast. Even small amounts of calories — including sweetened drinks, gum, or dairy in coffee — will trigger an insulin response and end the fasting state.

Who should avoid IF: Pregnant or breastfeeding women, people with a history of eating disorders, those with diabetes on medication, and individuals under 18 should consult a doctor before starting any fasting protocol.