Although OMAD is considered an extreme form of intermittent fasting, it’s actually really simple: Eat one large meal each day, within a one-hour time frame, and then fast for the other 23 hours. Aside from that, the only other real rule with OMAD is to stick to the same daily schedule.

That means, if you decide you’re going to eat between 3 p.m. and 4 p.m. (one of the most common eating windows for people following OMAD), that will be your ongoing eating window.

But while the OMAD diet outlines when to eat, there aren’t a lot of specific rules about what to eat. There’s no strict breakdown of macronutrients or calorie guidelines to follow. As long as you’re sticking to your eating window, you’re technically following OMAD.

That being said, as with any dietary plan, it’s always a good idea to make healthy choices when you do eat. Amy Shah, M.D. says, “Avoid carb-loaded meals and sugary drinks as they will cause a blood sugar roller coaster, raising your insulin levels and making you feel even more hungry."

Shah adds that refined carbohydrates aren’t just a problem in the moment, they also make fasting the next day even more difficult because hunger hormones, like ghrelin, will be raised and you’ll feel hungrier. During your hour eating window, try to stick to lean proteins, healthy fats, and plenty of vegetables.