16:8 is the most popular fasting schedule for a reason.

It’s simple. It works. And you’re basically already doing a version of it (unless you eat at 2am).

Here’s everything you need to know to start.

What Is 16:8 Fasting?

Fast for 16 hours. Eat during an 8-hour window.

That’s it. No calorie counting. No special foods. Just timing.

Example schedule:

  • Stop eating at 8pm
  • Skip breakfast
  • First meal at 12pm (noon)
  • Last meal by 8pm

You’re sleeping through most of the fast. It’s easier than it sounds.

Why 16:8 Works

1. Insulin drops

When you fast, insulin levels decrease. Low insulin = your body can access stored fat for energy.

2. Growth hormone increases

Fasting boosts HGH, which helps with muscle preservation and fat burning.

3. Cellular repair (autophagy)

Your cells start cleaning out damaged components. This kicks in around 12-16 hours.

4. Calorie reduction (naturally)

Smaller eating window = fewer opportunities to overeat. Most people eat 300-500 fewer calories without trying.

How to Start 16:8

Week 1: The Transition

Don’t jump straight into 16 hours. Build up.

Days 1-3: 12-hour fast (8pm to 8am) Days 4-5: 14-hour fast (8pm to 10am) Days 6-7: 16-hour fast (8pm to 12pm)

Week 2: Lock It In

Pick your eating window and stick to it. Consistency matters more than perfection.

Popular windows:

  • 12pm - 8pm (most common)
  • 10am - 6pm (early birds)
  • 2pm - 10pm (night owls)

What Breaks a Fast?

The short answer: calories.

Won’t break your fast:

  • Water
  • Black coffee
  • Plain tea
  • Sparkling water
  • Zero-calorie drinks

Will break your fast:

  • Milk in coffee (yes, even a splash)
  • Diet sodas (some say ok, but artificial sweeteners can trigger insulin)
  • BCAAs
  • Anything with calories

Gray area:

  • Bulletproof coffee (technically breaks the fast, but some people do this and still see results)
  • Sugar-free gum

Sample 16:8 Schedule

Morning (fasting):

  • 7am: Wake up
  • 7:30am: Black coffee or tea
  • 10am: Sparkling water
  • 11:30am: Getting hungry (normal, push through)

Eating window:

  • 12pm: First meal (break-fast) — protein + veggies
  • 3pm: Snack if needed
  • 7pm: Dinner — balanced meal
  • 7:45pm: Small dessert if you want
  • 8pm: Eating window closes

Evening (fasting begins):

  • 9pm: Herbal tea if needed
  • Sleep
  • Repeat

Common Mistakes

1. Breaking the fast with junk

Your first meal matters. Protein and fiber first. Donuts? Your blood sugar will spike and crash.

2. Not eating enough during the window

Some people under-eat and crash. You still need adequate calories — just compressed into 8 hours.

3. Obsessing over the exact time

15:45 won’t ruin your progress. Relax.

4. Drinking your calories

A latte with oat milk is 200+ calories. Save calories for food.

5. No tracking

You think you’re fasting 16 hours. You’re actually doing 14. Track it.

Tracking Your Fast

You can use a clock. Or your phone’s timer.

Or you can use an app that:

  • Starts automatically
  • Shows your fasting zone (fat burning, autophagy, etc.)
  • Sends reminders when your window opens
  • Tracks your streak

I built FastTrack for exactly this. One tap to start. Visual timer showing your progress. No guesswork.

Who Shouldn’t Do 16:8

Talk to a doctor first if you:

  • Are pregnant or breastfeeding
  • Have diabetes (especially Type 1)
  • Have a history of eating disorders
  • Take medications that require food
  • Are underweight

Probably fine but ease in if you:

  • Are new to fasting
  • Work out intensely in the morning
  • Have blood sugar issues

FAQ

Can I workout while fasting? Yes. Many people prefer fasted workouts. You might feel weaker at first while adapting.

Will I lose muscle? No, if you eat enough protein during your window (0.7-1g per pound of bodyweight).

How long until I see results? Most people notice something within 2 weeks. Real body composition changes take 4-8 weeks.

Can I do 16:8 every day? Yes. Many people do it 7 days a week. Some take weekends off. Both work.

What if I get really hungry? Drink water. It passes. Hunger comes in waves, not a constant climb.

Is 16:8 better than 18:6 or 20:4? 16:8 is the most sustainable for most people. Start here. Adjust later if you want.

Related reads:

— Dolce