The 16:8 fast, explained in plain English

The most common intermittent fasting schedule is called 16:8. It sounds technical. It isn't.

You don't eat for 16 hours. You eat during an 8-hour window. That's the whole thing.

What it looks like in practice

A typical 16:8 day:

• Last meal: 8pm
• Fast: 8pm → 12pm next day
• Eating window: 12pm → 8pm

You sleep through most of it. The hard part is the morning, and only for the first week or two.

What's happening in your body

Roughly, hour by hour:

• 0–4h: Digestion. Insulin is high. Energy from the meal you just ate.
• 4–8h: Blood sugar normalises. Body switches to stored glycogen.
• 8–12h: Glycogen depletes. Body starts pulling energy from fat. This is the part most people don't reach with three meals a day.
• 12–16h: Fat burning is meaningful. Insulin is low. Mental clarity for many people.
• 16h+: Autophagy ramps up. Cellular cleanup. The body recycles damaged components.

WAIT's timeline view shows this in real time, hour by hour, so you can see where you are.

How to start without hating your life

1. Don't start with 16:8. Start with 12:12. Just don't eat between 8pm and 8am. Most people already do this and don't realise.
2. Move the window an hour later each week. Push breakfast from 8am to 9am, then 10am, then 11am, then 12pm.
3. Drink water, black coffee, or plain tea during the fast. They don't break it.
4. Break the fast with protein and fat, not a pastry. Eggs, yogurt, nuts, avocado.

Things that aren't required

• Counting calories. (Though you can if you like.)
• Cutting out specific foods.
• Keto or any other diet on top.
• Suffering.

If you're suffering, your window is too aggressive. Shrink it.

When 16:8 isn't right

• If you're pregnant or breastfeeding, don't.
• If you have a history of disordered eating, talk to someone first.
• If you're an endurance athlete in training, your nutrition needs are different.
• If you have diabetes or take insulin, work with your doctor.

Otherwise — try it for two weeks. Use WAIT. See what changes.