By the Live Fitness Check editorial team • Reviewed for accuracy
Of all the fasting methods, 16:8 is the one most beginners actually stick with — because most of the 16 fasting hours happen while you are asleep. You fast for 16 hours, eat during an 8-hour window, and most people just skip breakfast and eat lunch and dinner. There is no special food to buy and no menu to memorize. Curious how it fits your schedule? Our free intermittent fasting calculator maps out your exact eating and fasting hours based on the window you choose.
The reason 16:8 works for weight loss has nothing magical about it. Eating in a shorter window makes it harder to overeat, because you get fewer hours and fewer opportunities to snack. Many people naturally eat 300–500 fewer calories a day without counting a single thing. But "naturally" is doing a lot of work in that sentence — if you pack the 8-hour window with extra-large meals, you can erase the benefit entirely. This guide covers how to set your window, what you can drink while fasting, what to eat when the window opens, and who should skip intermittent fasting altogether.
In 16:8 intermittent fasting you go 16 hours without calories (water, black coffee, and unsweetened tea are fine) and eat all your food in an 8-hour window — the classic version is noon to 8 pm. It helps weight loss mainly by making it easier to eat less, not through any special metabolic switch. Eat normal, balanced meals in the window, drink plenty of water while fasting, and talk to your doctor first if you are pregnant, nursing, take blood-sugar medication, or have a history of eating disorders.
Plan My Fasting Schedule16 plus 8 is 24 — the whole day is accounted for. A typical day looks like this: finish dinner at 8 pm, fast overnight and through the morning (that is 12 hours to 8 am, plus 4 more to noon = 16 hours), then eat from noon to 8 pm. Most people find the morning stretch easy because sleep covers roughly half of it. The hard part is usually 9–11 am, and black coffee was invented for exactly this problem.
Two things matter more than perfection here. First, the window can shift: if noon–8 pm clashes with your life, 10 am–6 pm or 11 am–7 pm work the same way — the math is identical (16 hours fasting, 8 eating). Second, consistency across days matters more than the exact clock time. Your body adapts to the rhythm; random fasting days feel much harder than a steady routine.
| Schedule | Eating window | Best for |
|---|---|---|
| Classic | 12 pm – 8 pm | Most beginners; pairs with a normal social dinner life |
| Early | 10 am – 6 pm | People who need a real breakfast or have an early bedtime |
| Middle | 11 am – 7 pm | Brunch fans and anyone with a 9-to-5 routine |
This is where most beginners overthink. The rule of thumb for 16:8: anything with effectively zero calories does not break the fast. Anything with calories does.
| Drink | Fast-safe? | Why |
|---|---|---|
| Water (still or sparkling) | Yes | Zero calories; drink plenty — fasting dehydrates |
| Black coffee (no sugar, no cream) | Yes | About 2–5 calories per cup; effectively zero and blunts hunger |
| Unsweetened tea (green, black, herbal) | Yes | Zero calories; green tea may slightly ease appetite |
| Water with lemon or cucumber | Yes | A squeeze of lemon is ~5 calories; fine |
| Diet soda / zero-calorie drinks | Probably | Zero calories, so technically fine, but artificial sweetness can sharpen hunger and cravings for some people |
| Coffee with cream or milk | No | One tablespoon of half-and-half is ~20 calories; a splash of milk adds up — the fast is broken by the rules most people follow |
| Bulletproof / butter coffee | No | 100–200 calories of pure fat; that is a meal, not a fast |
| Juice, smoothies, lattes | No | Obvious calories |
For the full rapid-fire list — gum, bone broth, apple cider vinegar, medications — see our guide on what breaks a fast.
Intermittent fasting is a when, not a what — but the what still decides your results. A fast followed by 3,000 calories of pizza is not a weight-loss plan. Build your eating window the same way you would build any sensible diet:
If you want a calorie target rather than winging it, find your maintenance level with the TDEE calculator, subtract 300–500 calories, and treat that as your window budget — the calorie deficit calculator walks you through it. Also plan your plate balance with the macro calculator so protein stays high while carbs and fat land where you want them.
Fasting dehydrates you faster than a normal day because you lose the water content of the meals you skip, plus caffeine is mildly diuretic. Headaches, afternoon fatigue, and "I think I'm hungry" are often just thirst wearing a costume. Drink water steadily through the fast — aim for roughly half your body weight in pounds as ounces per day as a baseline (a 180 lb person targets ~90 oz, about 2.7 liters), more if you exercise or it's hot. Our water intake calculator personalizes the target. A pinch of salt in morning water helps some people with fasting headaches, since you lose electrolytes overnight.
16:8 is simple, but it is not for everyone. Skip it — or get your doctor's explicit sign-off first — if any of these describe you:
Medication deserves its own bold rule: never skip or reschedule prescribed medication for the sake of a fast. If a drug must be taken with food, the drug wins and the fast adapts.
Do not start with 16:8 on day one if you currently eat from 7 am to 10 pm. Ease in: days 1–2, do 12 hours (8 pm–8 am — that is basically just not snacking after dinner). Days 3–4, push to 14 hours. Days 5–7, hit 16. Most people report the first three days are the hardest and then hunger hormones adjust. If you feel genuinely dizzy, shaky, or unwell at any point, break the fast and eat — a fasting schedule is not worth a medical event. And if 16:8 makes you miserable for two full weeks, it is not the right tool for you. The best diet is the one you can actually keep doing.
Disclaimer: This article is for general information only and is not medical advice. Talk to your doctor before starting a new diet or exercise program, especially if you are pregnant, have a medical condition, or take medication.
