Intermittent fasting plan

How is it calculated?

The window is simple: the eating hours of the protocol you pick, counted from the start time you give. For 16:8 a window opening at 12:00 closes at 20:00; the fast runs from 20:00 to 12:00 the next day. OMAD is handled as 23:1 in the maths, because a single meal still takes time and a zero-length window would divide by zero in the per-meal figures.

The meal count comes from the window, not from your choice: at least 3 hours between meals, and however many fit. Five in a 12-hour window, three in an 8-hour one, two in a 4-hour one, one for OMAD. That is a placement rule, not a digestion rule — eating more often than every 3 hours turns into one long meal in practice, and calling it "5 meals" says nothing.

Daily calories and protein do not come from a formula of this page but from the site's shared engine: Mifflin-St Jeor for basal metabolism, an activity multiplier, ±400 kcal for your goal, then 30% of daily calories as protein. For the example body that is 2,045 kcal and 153 g of protein — the calorie calculator page returns the same two numbers.

Per-meal calories and protein are the daily figure divided by the meal count, with the remainder written into the last meal. Rounding each meal separately pushed the total off target, so a three-meal day comes out as 682 + 682 + 681 and the total stays exactly 2,045.

The saturation figure is 0.4 grams per kilo of body weight: 33 grams per meal for the example body. That is not an upper limit. It is not a harm threshold either. It is the point where muscle protein synthesis saturates, meaning the surplus goes to energy rather than muscle. The marker in the table shows that; it does not say "you ate too much".

The "meals needed" line is daily protein divided by the saturation figure: 153 ÷ 33 = 4.6, rounded up to 5 meals. Then the narrowest protocol that reaches that meal count is looked up. If none does, the line says so too — at that protein target, going over saturation is unavoidable.

The sleep check compares the last meal with your bedtime and warns if the gap is under 3 hours. The gap is measured from the window start rather than by subtracting the two clock times: in a 12-hour window opening at 12:00 the last meal falls at 00:00, after a 23:00 bedtime — plain subtraction would read that as 23 hours and the warning would never appear.

How to read your result

Notice the order first: the page prints your daily calories before the hours. That is not a layout preference, it is the tool's claim. Intermittent fasting does not create a calorie deficit on its own; narrowing the window works because it lowers intake by itself for most people. Someone who squeezes the same 2,500 calories into 8 hours does not lose weight — they just eat faster.

In the protocol table, the column that matters is the last one. Calories per meal say little on their own: 1,023 kcal is large but eatable. Protein is the column that talks. For the example body, 16:8 puts 51 grams in each meal while the saturation figure sits at 33, and the 18-gram difference does not vanish; it simply goes to energy instead of muscle.

The "meals needed" line is this tool in one sentence. Your protein target and your per-meal saturation figure settle the window question for you: if you need 5 meals, 18:6 is out of the discussion, because only 3 fit there. If muscle is not one of your goals you can ignore this line; if you want to hold on to muscle while losing weight, this line is what picks the window.

If your training time falls outside the window, you are training fasted. That is not bad in itself. Plenty of people work this way, but how long it is until the first meal afterwards matters, because that is when the protein your muscles use for repair actually arrives. The tool prints that gap too.

The three-hour buffer between the last meal and sleep is a comfort line, not a safety limit: a large meal right before bed is associated with reflux and longer time to fall asleep. Wide windows can produce the opposite problem — the last meal lands after your bedtime. The tool reports these two separately because the fixes differ: one means moving the window earlier, the other means narrowing the protocol.

This tool is not recommending something suitable for everyone. Pregnancy, breastfeeding, type 1 diabetes, insulin or sulfonylurea use, a history of disordered eating, and adolescence — in none of these is intermittent fasting a decision a web page should make. If you take blood-sugar-lowering medication, skipping meals is a direct risk; ask your doctor before changing anything.