There are many different intermittent fasting schedules, perhaps the most popular being the 16:8 or 18:6. OMAD (one meal a day) is a stricter, 23:1 intermittent fasting schedule: you consume all your food in a 1-hour window, and fast for the rest of the day.

There isn’t much scientific evidence comparing one meal a day with other fasting schedules. Overall, although OMAD can result in a greater caloric deficit and reduce body weight, it’s not necessarily superior to other intermittent fasting schedules in achieving health benefits.

One study invited 13 metabolically healthy and fit participants to consume one meal a day for less than two weeks. Two people dropped out, and while those who succeeded did lose weight and improved their glucose control, such a short-term and well controlled study cannot replicate real-life. Also, the nutritional quality of the diet, and aspects of psychological well-being were not measured.

🤔 Would the participants keep on top of their health if this carried on for months or even longer?

It’s probably impossible to meet all your vitamin, mineral, protein, and fat needs from one meal sitting, because it’s more difficult for our gut to digest and absorb all of these at once.

Already most women don’t meet the recommended iron intake in 3 different meals per day. It’s also challenging to meet your protein needs in a single meal, since it could be utilised less efficiently but also because of protein’s effects on satiety and fullness.

There are few other disadvantages to OMAD. Having a single meal per day could eliminate the social component of eating: even if you had your one meal socially, you’d probably be more focused on eating and rather than sharing the experience with your loved ones.

In some way, OMAD reflects psychological conditions where people are prone to meal skipping, such as anorexia nervosa, and anecdotally, OMAD not done properly could cause fatigue, low energy, low mood, and poor mental clarity.

OMAD involves having all your daily calories in one sitting. While there’s no evidence to support OMAD over other intermittent fasting schedules, it has many risks to health and wellness. There are different fasting schedules which may better suit your needs, lifestyle, and overall health and well-being. Remember, it’s the nutrition strategy that should suit your life, not the other way around.

If you feel ready to try a more challenging intermittent fasting schedule, such as OMAD, speak to a dietitian first to make sure your approach is safe and nutritionally complete.