With OMAD you eat at your caloric needs. Use a tdee calculator like https://tdeecalculator.net and if you’re goal is weight loss, aim to eat below your resting/maintenance number.
OMAD is considered 23:1 - one hour of eating during the day. If you need more time to make sure you’re getting your required calories and nutrients, then take more time.
And it’s not binging. These OMAD meals should be planned out and consist of quality nutritional foods. This is more important on OMAD than any other IF method since you only have one shot at getting the nutritional needs met during the day. On other plans, like 16:8, you have 8 hours and multiple meals, so if you’re having a meal that’s not that great, you can make up for it later.
Yep, you’re putting all your calories into one meal - so even on a deficit it can be a lot. If you focus on good calorie dense foods it’s certainly doable.
However, there is no set calories. You would look up your TDEE to see around where your maintenance level is for you and your body. If you want to maintain your weight eat that amount. If you want to lose weight, start by substracting a few hundred calories from that daily amount. Cutting 500 calories a day is roughly a pound of weight loss a week.
I did mostly OMAD for weight loss. For dinner I tried to have a fairly low carb meal of meat and veggies, and/or salad with oil and vinegar dressing usually with cheese. It was definitely bigger than I used to eat but not a feast by any means. I ate to satiety. No further. I can’t say how many calories because I never tracked a single meal.
Sometimes I was still hungry after dinner and would have nuts or cheese. Maybe some seafood salad. I didn’t want to be hungry post meal.
The idea was I’d “eat” stored body fat as meals during the fasting period and it worked. Lost about 50lbs in a little over 6 months with ease.
A 1500 calorie meal doesn’t have to be a brick in your stomach. It’s easier to eat that many calories in one meal than you’d think, your typical appetizer + main course + dessert at a restaurant easily meets or exceeds that threshhold.
But if you can’t eat your desired amount of calories in one meal and think eating lower amounts would be harmful to your goals, here’s a really easy calorie boost: Stir some coconut oil into a cup of coffee. That stuff is extremely calorie dense and won’t leave you feeling bloated.