Diet 101: OMAD Diet

We take a deep dive into intermittent fasting and what it means for your health.

Photo by: Nicola Margaret/Getty Images

Nicola Margaret/Getty Images

Eating OMAD (aka one meal a day) is gaining momentum, but turns out it’s not exactly a “new” thing. Find out if this ultra-extreme version of intermittent fasting is a good idea.

What Is OMAD?

While intermittent fasting can vary in how it’s executed, OMAD is more straightforward: Eat for just 1 hour per day and spend the other 23 fasting. The one meal should be eaten within the same 4-hour window each day. That meal also has guidelines – it must be served on nothing larger than a dinner plate and to prevent piling too much food onto the place, there is a 3-inch limit. Dieters can technically can eat whatever they want for this one meal, some resources suggest the calorie limit should be somewhere between 800 and 1000 calories and only calorie-free beverages are allowed.

Is OMAD a Good Idea?

If you want to OMAD for weight loss, this extreme calorie cut off will likely help — at least in the short term. Registered Dietitian Nutritionist, Malina Malkani, MS, RDN, CDN, Media Spokesperson for the Academy of Nutrition and Dietetics and Creator of the Charitarian™ Lifestyle points out another potential upside: “Supporters of the diet claim that it allows them a sense of freedom to eat whatever they want during their one meal per day and still lose weight.” It is unclear how many folks following this diet are eating balanced meals, but eating as many nutrient dense foods as possible would be encouraged to help meet nutrient needs. Ideally, dieters would reach for a variety of nutrient dense foods like fruits, vegetables, lean protein, healthy fats and low-fat dairy (or a dairy alternative) at each meal, but according to the diet rules, they could eat a cheeseburger and fries every night, too.

What Are the Downsides?

It’s pretty clear since this style of eating is so strict, long term compliance is not likely – and getting hangry is pretty much guaranteed. And even if you do have the chops to eat like this for the long haul, you may be putting your health a risk. The calorie deficit would likely promote muscle breakdown, especially in folks that don’t have a lot of weight to lose, and nutrient deficiencies would be very likely. Malkani agrees, “ I don’t recommend OMAD because extreme fasting diets like this are unlikely to provide a wide enough range and adequate amount of nutrients which can lead to negative health effects.”

Your overall relationship with food may also be in jeopardy. “People undergoing a daily 23-hour fast on the OMAD diet are more likely to develop on unhealthy focus on and relationship with food, which can significantly reduce their overall quality of life,” adds Malkani.

There is very little research looking at this restricted style of eating and none has been done since its recent resurgence in popularity. A study from 2007 shows that normal-weight subjects with reduced meal frequency were able to lose some weight and body fat over the 6-month experiment, but some also demonstrated increases in blood pressure and LDL cholesterol.

Bottom Line: OMAD is a hyped-up fad diet worth skipping. Eat more frequently to prevent nutrients deficiencies and to protect your healthy relationship with food.

Dana Angelo White, MS, RD, ATC, is a registered dietitian, certified athletic trainer and owner of Dana White Nutrition, which specializes in culinary and sports nutrition.

*This article was written and/or reviewed by an independent registered dietitian nutritionist.

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