If you follow weight loss trends, then you’ve probably heard about intermittent fasting—which has dieters forgoing food for up to 16 hours , then consuming their meals during the remaining eight hours of the day. It’s restrictive, but not crazy-grueling.
The OMAD diet, however, takes this to the extreme. OMAD stands for One Meal a Day; the idea is to fast for 23 hours straight and then consume one large meal in a 60-minute window. Lately OMAD has been gaining popularity, with people swearing by it as a weight loss method as well as a way to tackle chronic disease and other health issues.
To find out what the OMAD diet is all about and whether it can really help you reach your weight loss and health goals, we asked two nutritionists to give us their take.
How to follow the OMAD diet
Like many diets, OMAD has a host of rules. For starters, your one meal should be eaten in the same four-hour time block every day, so you eat on a consistent schedule. You’re allowed to drink beverages during your 23-hour fast, but they have to be the calorie-free kind, like black coffee or water, explains Dana Angelo White, RD, a sports dietitian based in Connecticut and author of Healthy Instant Pot Cookbook.
You also must consume your one meal on a standard dinner plate—nothing larger. (Sorry, bowl fans.) And no piling on heaping amounts of food. Whatever you choose to eat can’t rise higher than three inches on your plate. “Other than that, dieters can (in theory) eat whatever they like,” says White.
That’s the upside to OMAD: You don’t really need to consider your calories or worry about the exact nutritional profile of the food you eat, as long as you’re saving all of your calories for that one period of time, says New York City–based nutritionist Natalie Rizzo, RD, author of The No-Brainer Nutrition Guide For Every Runner. So if you’re someone who dislikes tracking and crunching numbers, OMAD has appeal.
Can OMAD lead to weight loss?
This is an extreme level of intermittent fasting, no doubt. But Rizzo notes that there is some positive research surrounding fasting in general, showing that fasting could aid in weight loss as well as assist in preventing chronic disease. “Other research suggests that intermittent fasting helps regulate blood glucose level, which may be therapeutic for those with diabetes,” she says.
Yet whatever weight loss or health benefits you see on the OMAD diet will likely be short-lived. The drawbacks are obvious: Not eating for 23 hours will probably lead to serious hunger, lack of energy, fatigue, and uncontrollable cravings, says Rizzo.
What’s more, fasting for so long might make you so famished, you end up choosing the wrong foods when it is time to eat, like greasy fries and double bacon burritos. True, these are allowed on the diet; no food is off-limits for your one-hour meal. But face-planting in high-fat, low-nutrition foods could leave you taking in more calories than you need, not to mention cause stomach discomfort and mood changes.
“When someone deprives themselves of food for 24 hours, they tend to lose control and overeat when it’s time to eat again. This can lead to choosing unhealthy options and eating way more than what feels natural in one sitting,” says Rizzo.
Plus, it’ll be tough getting enough of the nutrients your body needs each day. “Joking aside, it would be fantastically difficult to meet your nutrient needs eating this way,” says White. “Sure, a well-balanced multivitamin and omega-3 supplement would be helpful, but I would still have concerns about dieters meeting their needs.”
Any calorie deficit you achieve would also likely promote muscle breakdown, as your body turns to burning muscle for energy. If you’re an athlete or are trying to build strength, the OMAD diet can backfire.
If you do the OMAD diet, what should you eat?
If you decide to do the OMAD diet, don’t fall into the trap of scarfing down anything you crave. “The diet allows you to eat whatever you want,” says Rizzo. “Personally, I would suggest a well-balanced meal with healthy carbs, protein, and healthy fats.” Since you’re trying to make up for the calories you skipped throughout the day, feel free to load up on foods with lots of healthy fats, like avocado, olive oil, and nuts, she suggests.
Also important: add in variety. “Because our nutrient needs are so diverse, variety would be essential. Mix it up by eating different things every day so you don’t miss out on nutrients,” suggests White.
You probably shouldn’t do it, though
Both Rizzo and White agree: the OMAD diet isn’t a sound one. Says Rizzo: “I would not recommend this diet. I think it’s entirely too restrictive and can lead to choosing unhealthy options. If I starved myself all day, I would be more inclined to eat a pizza than a piece of fish with veggies.”
If you do want to try intermittent fasting, at least go with the 16:8 method, which has you fasting for 16 hours and eating for eight. It’s not for everyone, but it’s a much more balanced approach, Rizzo says.