The One Meal a Day Diet Oversimplifies Nutrition—and May Backfire

First, lets look at the weight loss claim.

In intermittent fasting terms , OMAD is a 23:1 approach. That means you fastor dont consume anything with caloriesfor 23 hours and do eat during the other available hour of the day. There are two main camps within OMAD. The first advocates that because youre only eating for one hour out of the day, you can eat whatever you want during that hour. The second recommends eating healthful foods.

Cheese-flavored Pizza BusinessInsider USA Images

Could either of these approaches help you lose weight? Sure.

Thats because you can only eat so much in one hour, regardless of if that foods is a large meat lovers pizza with extra cheese or a few grilled chicken breasts and a pile of steamed broccoli.

In other words, youll eat drastically lessregardless of what youre eatingand by eating less youll likely lose weight.

But good nutrition is about so much more than just total calories consumed. Quality matters.

middle aged man eating noodles while sitting on the floor BusinessInsider USA Images

Consider a recent study published in the British Medical Journal that found that people who eat four servings of ultra-processed foods daily had a 62 percent higher risk of dying from all causes compared with those who ate only two servings per day.

The fact that some people use OMAD to blindly eat whatever they want (say, four servings of mac n cheese, for example) doesnt promote proper nutrition and, in fact, hinders them.

On the flipside, if you adopt the OMAD diet and try to eat nutrient-rich foods during your one hour of eating, its still hard to consume all the nutrients your body needs in a day. Thats because nutrient-rich foods tend to be loaded with fiber and protein, which fill you up fast during a meal.

Yes, this makes it nearly impossible to overeat, but even though youre physically full, that doesnt mean youve taken in an adequate amount of nutrients.

Beautiful sleepy man having breakfast at the table BusinessInsider USA Images

Frances Largeman-Roth, R.D.N., and author of Eating in Color, agrees with me. It doesnt seem possible to get all of your nutrients in during one sitting. People are already getting so few fruits and vegetables these days (only 1 in 10 of us gets enough), Id hate to put additional and seemingly purposeless restrictions on anyone.

And then theres the fact that active people require more nutrients than sedentary people.

I cant imagine that its easy for most athletes and active people to feel their best on a diet like this, Largeman-Roth says. If you cant refuel after a workout, how can your body repair itself? Further, a one meal a day diet certainly isnt appropriate for teens, people with diabetes or any medical condition, and it would be ill-advised for anyone with a history of disordered eating.

And, to that point, food isnt just utilitarian. Eating should be enjoyable actnot something you check off a to-do list.

Creative businessman working and eating pizza and drinking beer at desk BusinessInsider USA Images

I think of the one-day diet as trying to ask for extra credit in math class after youve failed everything, says Heather Leidy, Ph.D., Assistant Professor in the Department of Nutritional Sciences of at the University of Texas, Austin. Eating healthy to promote health and well-being is not going to occur with a single day and a few foods to avoid. Its a lifestyle that requires a daily commitment.

Where I can confirm the OMAD will help you?

It will surely free up time during your daypreparing, cooking, and eating requires time.