The OMAD diet explained: safety and health benefits of one meal a day

The most effective diet is one that nourishes your body, aligns with your lifestyle, is economically viable, and prioritises sustainability over quick fixes.

The most effective diet is one that nourishes your body, aligns with your lifestyle, is economically viable, and prioritises sustainability over quick fixes.

Published Mar 6, 2025

Share

The OMAD (One Meal a Day) diet has captured the imagination of health enthusiasts across South Africa and beyond.

This distinctive eating regimen, which advocates for consuming all your daily calories in one large meal after a prolonged fasting period of 23 hours, promises simplicity in a world often overwhelmed by dietary confusion. Yet, beneath this seemingly straightforward approach lies a deeper conversation about its safety and long-term health implications.

The OMAD diet is a unique aspect of intermittent fasting, a growing trend that emphasises the idea that fasting can facilitate weight management and even enhance detoxification. Proponents argue that by limiting the feeding window to just one hour each day, individuals may boost their metabolism and promote fat loss.

Some emerging studies have suggested that adhering to such a restrictive diet could offer protective benefits against chronic health conditions such as diabetes, a notion that has piqued the interest of many who are eager to improve their overall wellness.

However, the diet is not without its detractors. Critics warn that such extreme calorie restriction can lead to nutritional deficiencies, fatigue and heightened feelings of hunger. This could potentially result in binge eating - counteracting any purported benefits of weight loss and health improvement.

For many,the challenge of enduring hours of fasting can lead to irritability and a lack of energy, making it difficult for individuals to sustain their usual daily activities.

The OMAD diet is a unique aspect of intermittent fasting, a growing trend that emphasises the idea that fasting can facilitate weight management and even enhance detoxification.

To delve deeper into the complexities of the OMAD diet, we turned to dietitian Mbali Mapholi, who shared her insights on the potential benefits and pitfalls of this eating strategy. 

The upside of the OMAD diet

Mapholi highlights several potential benefits that may entice individuals to try the diet:

  • Weight loss: with calorie consumption limited to one meal, weight loss is a likely outcome for many participants. 
  • Simplicity: this diet removes the burdens of meal prepping and calorie counting throughout the day, allowing individuals to focus solely on their one meal.
  • Potential metabolic benefits: preliminary research suggests that fasting may enhance insulin sensitivity and reduce inflammation, contributing to improved overall health.

The downsides of the diet

However, Mapholi cautions against the potential pitfalls of the OMAD lifestyle:

  • Nutrient deficiencies: squeezing all vital vitamins, minerals, and macronutrients into a single meal can be exceptionally challenging, leading to deficiencies over time.
  • Extreme hunger and energy dips: the long fasting period can provoke fatigue, irritability and dizziness, often resulting in an unpleasant state of being "hangry."
  • Muscle loss: extended fasting can induce muscle breakdown, particularly if protein intake is insufficient. 
  • Disruption of metabolism and digestion: consuming a large meal at once may cause bloating and discomfort, not to mention that prolonged fasting could slow metabolism over time - a phenomenon that often affects females more than males.
  • Not sustainable for most people: while OMAD may be doable in the short term, maintaining it long-term presents challenges, particularly when considering social situations and varying energy needs.

Is OMAD the right choice for you?

The question remains, should you embark on the OMAD journey?

According to Mapholi: "OMAD might work short-term for some people but it’s not a one-size-fits-all solution. If someone enjoys fasting and can still meet their nutritional needs in one meal, it could be an option. However, for most people, a balanced approach with regular meals is healthier and more sustainable."

She further emphasises that a better long-term strategy involves focusing on a well-balanced diet, portion control and mindful eating instead of extreme fasting.

The ultimate takeaway? The most effective diet is one that nourishes your body, aligns with your lifestyle, is economically viable and prioritises sustainability over quick fixes.