18:6 Fasting Schedule Planner & Timer

Fast for 18 hours and eat within 6. The 18:6 plan is already selected: set when your last meal ends to see when to break your fast and when your window closes, with the body stages along the way, then start the live 18-hour timer.

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Choose your fasting plan

My last meal ends at

Fast begins: 8:00 PM
Window opener meal: 2:00 PM next day
Eating window: 6 hours
Window closer meal: 8:00 PM next day

Cellular Renewal & Body Insights Timeline

1
0–4h · from 8:00 PM
Blood Sugar & Insulin Stabilization
Your last meal is being digested. Blood sugar rises, then insulin brings it back to a steady level.
2
4–12h · from 12:00 AM next day
Glycogen Depletion & Digestive Rest
Insulin falls and your body draws on the sugar stored in your liver (glycogen) while digestion rests.
3
12–16h · from 8:00 AM next day
Fat Burning & Metabolic Switch
With glycogen running low, your body turns increasingly to stored fat for fuel.
4
16h+ · from 12:00 PM next day
Mild Ketosis & Cellular Renewal (Autophagy)
Ketone levels rise. Research suggests autophagy, the body’s recycling of worn-out cell parts, steps up with longer fasts.

Timings are typical averages and vary with your last meal, activity and metabolism.

Live fasting timer

Keeps counting even if you close this tab. Saved on this device only.

JaxFit gives general wellness information, not medical advice. Talk to a doctor before fasting or changing your diet if you are pregnant or breastfeeding, have diabetes or another medical condition, take regular medication, or have a history of eating disorders.

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Guide

A Simple 18:6 Day

A typical 18:6 day: finish dinner by 8 PM, sleep, drink water, black coffee or plain tea through the morning, and eat your first meal at 2 PM. Your eating window runs from 2 PM to 8 PM, which usually fits two meals.

18:6 keeps you past the 16-hour mark, when ketone levels start to rise, for two extra hours each day. It's a natural next step once 16:8 feels easy; jumping straight in often means a hungry, tired first week.

Because the window is short, make both meals count: protein, vegetables, whole grains and some healthy fat. Check your daily calorie target in the BMI & Calories tab so you eat enough, not as little as possible.

Step by step

How to Plan Your 18:6 Fast

1
Keep 18:6 selected
The 18:6 plan (Deep Metabolic) is chosen for you. You can switch to 16:8 or 20:4 at any time.
2
Set your last meal
Enter the time your last meal ends, for example 8 PM, to see your fast and your 6-hour eating window.
3
Check the body stages
See when you reach each stage, including the 16-hour mark when mild ketosis begins.
4
Start the live timer
Tap Start to time your 18-hour fast. It keeps running even if you close the tab.

Private by design

Your Health Data Stays on Your Device

Every calculation runs in your browser. Nothing you enter is uploaded or sent anywhere.
No accounts, no analytics cookies, no tracking scripts and no ads.
Your details, timer and garden are saved only on this device. Clearing your browser data removes them.

FAQ

Frequently Asked Questions

How do I start an 18:6 fasting schedule?

Choose when your last meal ends, for example 8 PM. Your fast then runs until 2 PM the next day, and you eat between 2 PM and 8 PM. Most people get there from 16:8 by moving their first meal an hour later each week. Drink water, black coffee or plain tea in the morning, and make your two meals filling, with plenty of protein and vegetables.

Is 18:6 better than 16:8 for weight loss?

18:6 gives you two more hours in the fasting stages each day and a shorter window, which makes it easier for some people to eat a little less. But weight loss mostly comes from your overall calorie balance, and the best plan is the one you can keep up. If 18:6 leaves you very hungry, irritable or eating too much in your window, 16:8 is just as good a choice.

What happens to your body during a fast, hour by hour?

In the first 0–4 hours your last meal is digested and insulin brings blood sugar back to a steady level. From about 4–12 hours insulin falls and your body uses the sugar stored in your liver (glycogen) while digestion rests. Around 12–16 hours glycogen runs low and your body switches more to burning stored fat. After about 16 hours ketone levels rise (mild ketosis) and research suggests autophagy, the body's recycling of worn-out cell parts, increases. These timings are typical averages: your meals, activity and metabolism shift them.

What should I eat to break a fast?

Open your eating window with a balanced, gentle meal: some protein (eggs, yoghurt, lentils, fish or chicken), fibre-rich vegetables or fruit, and a source of healthy fat. Avoid breaking a long fast with a very large or very sugary meal. Drinking a glass of water first helps too. Within your window, aim to eat enough overall: fasting is about when you eat, not about eating as little as possible.

Who should not try intermittent fasting?

Intermittent fasting isn't suitable for children and teenagers, during pregnancy or breastfeeding, for people with a history of eating disorders, or for anyone underweight. If you have diabetes, take medicines that lower blood sugar or blood pressure, or have another medical condition, talk to your doctor before you start. Stop and eat if you feel dizzy, faint or unwell.

Is my health data private on JaxFit?

Yes. Every calculation runs in your own browser. Your age, weight, goals, fasting timer and Habit Garden are saved only in your browser's local storage on this device, so they're there when you come back. Nothing is uploaded, there are no accounts, no analytics cookies, no tracking scripts and no ads. Clearing your browser data removes everything.