What is 16:8 fasting?
You fast for 16 hours and eat within an 8-hour window. Many people start with 13–16 hour overnight fasts as an entry point for time-restricted eating.
Intermittent Fasting Timer
16:8 and 18:6 are the most common intermittent fasting windows — fast overnight and into late morning, eat within a compressed window. This timer helps you see the clock; the guides help you decide whether the schedule fits your life and medications.
How to use this
- Choose water-only or assisted fasting and pick your goal hours.
- Tap Start fast when you finish your last bite. When you reach your goal, we show how to break the fast with meal ideas.
- Stage labels mark educational time windows only — they do not prove biological processes occurred.
Optional: Dr. Boz Ratio (glucose ÷ ketones)
Formula: glucose (mg/dL) ÷ ketones (mmol/L). Interpretations are educational only — not diagnostic targets. See our ratio guide for limitations.
Breaking intermittent fast (≤18h)
Shorter fasts (16:8, 18:6) are the easiest to break. A balanced low-carb meal with protein, healthy fat, and fiber is a common starting point.
How to break your fast
- 1Open your eating window with a balanced low-carb meal — not snacks or grazing.
- 2Prioritize protein (eggs, chicken, fish, cottage cheese) plus healthy fat.
- 3Add non-starchy vegetables or a small side of greens for fiber.
- 4Eat when hungry, stop when full — your first meal after IF is not an excuse to overeat.
- 5Stay low carb if that matches your eating plan.
What to avoid
- • Breaking with toast, oatmeal, or cereal if you are following a low-carb plan.
- • Sweetened coffee drinks or "keto" bars loaded with sugar alcohols as your first bite.
- • Skipping protein and eating only nuts or cheese — balance matters.
Tips
- 16-hour fasts are a common entry point for time-restricted eating — break them with real food: protein, fat, and fiber.
- On lower-carb eating, hunger often stays moderate — your first meal can be lunch-sized. No need to "make up" missed calories.
- Optional Dr. Boz Ratio tracking after eating is for personal observation only; it is not a treatment target.
Suggested break-fast meals
All recipesbreakfast
Scrambled Eggs with Spinach
Quick high-protein breakfast with minimal net carbs. Blood-sugar-friendly start for keto and insulin resistance meal plans.
~2g net carbs · 18g protein
dinner
Taco Bowl (No Tortilla)
All the taco flavor in a bowl — seasoned beef, avocado, cheese, and salsa without the wrap.
~9g net carbs · 26g protein
snack
Greek Yogurt with Berries
Higher-protein snack with controlled berries — fits moderate low carb more than strict keto.
~10g net carbs · 15g protein
dinner
Zucchini Noodles with Meat Sauce
Classic meat sauce over zoodles — comfort food with a fraction of the pasta carbs.
~9g net carbs · 24g protein
dinner
Sheet Pan Sausage & Peppers
One-pan dinner with minimal cleanup — hearty, low carb, and easy to scale for meal prep.
~7g net carbs · 18g protein
lunch
Lettuce Wrap Burger Bowl
Deconstructed burger with seasoned beef, cheese, pickles, and sauce over greens — about 4g net carbs, ideal for insulin resistance lunches.
~4g net carbs · 28g protein
breakfast
Shakshuka with Spinach & Feta
One-skillet eggs in spiced tomato sauce with wilted spinach — about 5g net carbs, high protein, and a satisfying break-fast or weekend brunch.
~5g net carbs · 20g protein
Not medical advice. This timer tracks clock time only. Talk to your doctor before fasting — especially on diabetes, blood pressure, or kidney medications. Do not adjust medication on your own.
Fasting timer
16:8 vs 18:6 — which to start with
16:8 (16 hours fasted, 8-hour eating window) is the usual entry point. 18:6 adds two hours of fasting — some people find it manageable without jumping to 24-hour fasts.
See intermittent fasting 16:8 vs 18:6 for schedule examples. Evidence does not support universal fasting schedules by sex or menstrual-cycle phase.
IF with low carb or keto
Lower carb intake often reduces hunger — many people naturally fall into 16:8 without forcing it. Pair fasting with adequate protein at meals to preserve muscle mass — protein on keto.
If insulin resistance is your main goal, also read fasting with IR before stacking aggressive windows.
What to eat in the window
Compressed eating is not a license for ultra-processed carbs. Build meals from the recipe index — protein, vegetables, and fats that match your macro plan from the keto or low carb calculators.
Related guides
Frequently asked questions
Does keto make fasting easier?
When carbs stay lower, hunger often drops within days and many people naturally skip meals — intermittent fasting can follow without forcing it.
Can women do 16:8 every day?
Evidence does not support universal fasting schedules by sex or menstrual-cycle phase. Stop and seek advice if fasting contributes to dizziness, sleep disruption, menstrual changes, or restrictive eating.
Other calculators
Metabolic Low Carb Calculator · https://metaboliclowcarb.com