Omad Diet: Dieticians Explain What Happens if You Eat Just One Meal a Day

OMAD Diet One meal a day intermittent fasting starvation mode high dropout rate nutrient deficiencies caloric deficits weight loss

By Lili Scott , Parent Herald Jan 31, 12:17 am

Photo: (Photo : ED JONES/AFP via Getty Images)

The OMAD diet, or eating just one meal a day, is the latest diet fad that allows a person to lose weight. In a one-hour window, someone on this diet is supposed to eat whatever he wants within his preferred hour and then practice intermittent fasting for the rest of the 23 hours.

However, dieticians do not recommend this type of intermittent fasting as skipping meals was never seen as healthy. Dietician Kelsey Hampton said that eating one meal a day can't provide the body with the daily calories it needs. Ideally, Hampton said people shouldn't consume under 1,200 calories a day to maintain their health.

How Does OMAD Diet Work?

There are studies that show people observing the OMAD diet have less body fat, have ideal cholesterol and glucose levels, or achieve a weight loss of about seven to 11 pounds after ten weeks. The OMAD diet has no strict rules on what food to eat or avoid. However, those following this diet are expected to hydrate throughout the day, so they can drink water, coffee, or tea but no other diet beverages.

However, those who habitually observe fasting at night and then have their one big meal at the same time every morning seem to lose weight faster than those who skip breakfast and lunch and then have a full meal with high calories by dinner. Hampton cautioned that the amount of calories consumed is based on the person's age, weight, height, and gender, so this diet might not work for some body types. The OMAD diet has a high dropout rate of 65 percent because it is not sustainable for most people.

Melissa Rifkin, a dietician from New York City, said some people could feel weak and sick for following the OMAD diet because they tend to overeat during their one hour of mealtime. She noted that overeating could trigger a surge of insulin in the body, making the person unwell.

Dio Balootje, 37, said that she quickly felt tired after having one meal a day because her body had difficulty taking and processing everything at once. But when she persisted with the diet, her body adjusted and felt her metabolism eventually increasing; thus, she lost 35 pounds in seven months.

But dietician Trisha Best told EatThis, NotThat, that a limit of just one meal a day could prevent the body from getting all the minerals, vitamins, and macronutrients it needs, especially if the person is not eating nutrient-dense food items and largely relying on processed foods. Thus, those on an OMAD diet could risk having nutrient deficiencies and caloric deficits.

Maggie Michalczyk, another dietician, said that the OMAD diet puts the body in starvation mode and will hold off processing the energy it receives from food until the next meal. It could impact the hormones by ignoring the hunger signals and compromise the body's immune and endocrine systems. She said this is not a sustainable way to lose weight and still be healthy.

Options for the OMAD Diet

The experts advised anyone considering an OMAD diet or any type of intermittent fasting to talk to a dietician or nutritionist to understand how they should be getting the proper nutrients. OMAD diet should be seen as a lifestyle and not a diet trend. People with diabetes and other health conditions, kids, and the elderly should never do this diet.

The dieticians said that a less extreme type of intermittent fasting, where people could eat within a four-hour or eight-hour window, might be better than an OMAD diet. Some studies show a feeding pattern between 9 a.m. to 3:00 p.m. could help improve insulin sensitivity, blood pressure, and pancreatic function.