OMAD Calorie Calculator

One Meal A Day, with the math made honest. Enter your stats, pick a cut, and see your single-meal calorie target — plus a sanity check on whether that's actually possible to eat in one sitting.

Your Stats

Gender

Your Results

Faster fat loss; hungrier days, especially with one meal.

Your OMAD single-meal target
—
calories in one sitting
Enter your stats to see a meal target.
Protein floor
—
0.9 g/lb bodyweight
% from protein
—
of the meal

How OMAD math actually works

OMAD — One Meal A Day — is a fasting protocol where you eat all of your daily calories in a single window, usually 1 hour. The internet treats it like a metabolic hack. It isn't. OMAD works for one reason: a one-hour window makes it physically hard to overeat. The fat loss comes from the deficit you create, the same way every other approach does.

The calculator above takes your TDEE, applies a deficit you choose, and that's your single-meal target. Mild cut, moderate cut, aggressive cut — pick based on how fast you want to lose and how much hunger you can absorb. There's no separate "fasting bonus" baked in, because in controlled studies there isn't one.

The 1,500-calorie ceiling problem

For most people, eating much more than ~1,500 calories in a single sitting is genuinely hard. You get full. Stomach volume is real. That's why OMAD works as a weight-loss tool — but it's also why OMAD is a poor fit for anyone above a 2,000-calorie target. If you're a 200-lb male with a 2,800 TDEE and you pick a mild cut (~2,400 cal), good luck eating that in one sitting. You'll inadvertently undereat, which sounds great for fat loss until you realize how hungry the next 23 hours become.

The calculator flags this. If your meal target lands above 1,500 cal, you'll see an honest warning to consider a wider window (like 16:8) instead.

Protein in one meal

Protein is the macro you protect first, especially in a deficit. On OMAD, the protein floor stays the same — ~0.9 g per lb of bodyweight per day — but you have to consume it all in one sitting. For a 175-lb person, that's ~160 g of protein in one meal. Possible, but it requires a real anchor:

  • 8 oz grilled chicken breast: ~70 g protein
  • 1 cup cottage cheese: ~25 g protein
  • 3 eggs: ~18 g protein
  • 1 scoop whey isolate: ~25 g protein
  • 200 g Greek yogurt for "dessert": ~20 g protein

That's ~160 g across one plate. Doable. Pleasant? Subjective.

Who OMAD works for

OMAD tends to work for people who:

  • Hate planning meals all day and prefer one decision instead of four
  • Have steady appetite suppression once they're a few weeks in
  • Are at a moderate body weight where the single-meal calorie target stays under ~1,600
  • Aren't training heavily (OMAD on a hypertrophy block is usually suboptimal)

Who OMAD doesn't work for

  • People with a history of binge eating — a single eating window can normalize huge portions
  • Anyone with morning training sessions (you fast through them)
  • Larger athletes whose calorie needs make the single meal physically impossible
  • People with social schedules built around lunch or breakfast meetings

If you're curious about other fasting protocols, see our 16:8 macro calculator or the 5:2 diet calculator. If you want the underlying calorie math without a fasting frame, the TDEE for weight loss page is the most direct path.

Frequently asked questions

Does OMAD have any magic over a normal calorie deficit?

No. OMAD works because compressing your eating into one window tends to lower total calories — not because of any metabolic effect of fasting itself. The autophagy claims you see online are exaggerated; the deficit is what drives fat loss.

Why does my single-meal target seem so big?

If your TDEE is high and your deficit is mild, OMAD math will produce a 1,800–2,200 cal single meal. For most people, that's hard to physically eat in one sitting without getting uncomfortably full. The calculator flags this — consider a wider window (like 16:8) instead.

Can I hit my protein floor in one meal?

It's doable but tight. 150 g of protein in one sitting takes a serious anchor: 8 oz of chicken breast (~70 g) plus a tub of cottage cheese (~25 g) plus a whey shake (~25 g) plus eggs (~15 g) gets you there. Spreading across two meals (16:8) is easier.

Will I lose muscle on OMAD?

Possibly, if protein is low or training is heavy. Muscle protein synthesis runs on a per-meal cap (~30–40 g effectively used at once). Eating all your protein in one bolus is suboptimal for hypertrophy, though for general fat loss with adequate total protein it's largely fine.

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