Is Eating Once a Day Actually Good for You?

In a world where wellness trends move faster than facts, it has become increasingly easy to confuse what’s popular with what’s actually healthy. From intermittent fasting to extreme diet routines, social media has transformed everyday habits into high-performance lifestyles, and right now, one trend dominating the conversation is OMAD (One Meal A Day).

It promises discipline, weight loss, and control. But beyond the aesthetics and glowing testimonials, a more important question lingers: what is it really doing to the body?

For World Health Day, GLAZIA is bringing expert insights to a conversation that often prioritizes virality over science.

We speak with Dr. Moyosore Makinde, a Consultant Family Physician and International Board-Certified Lifestyle Medicine Physician, who currently serves as President of the Society of Lifestyle Medicine of Nigeria and Head of the Department of Family Medicine at Lagos State University Teaching Hospital. Widely regarded as a leading voice in preventive health, Dr. Makinde has built her career around empowering individuals to take control of their wellbeing through sustainable lifestyle choices.

Joining her is Lola Oyewole-Udabor, an Integrative Health Coach and founder of Trim & Fettle and Breathe Woman, whose work focuses on helping high-performing individuals build consistent, realistic habits around food, fitness, and everyday wellness. With over two decades of professional experience and a growing influence in the wellness space, Lola brings a grounded, practical perspective to the conversation.

Together, they unpack the science behind OMAD: what happens physiologically, who it may benefit or harm, and why not every “healthy” trend is designed for every body.

Dr. Moyosore Makinde

Glazia: From a clinical standpoint, what happens to the body physiologically when someone restricts all eating to a single daily meal?

Dr. Makinde: To start with, eating one meal a day, typically referred to in recent times as OMAD, is a type of intermittent fasting where a person eats all their daily calories within a single meal (usually within a 1–2 hour window) and fasts for the remaining 22–23 hours. However, it is an extreme type of intermittent fasting that leads to several metabolic shifts. 

Let me break it down. When someone eats just one meal a day, the body goes for long hours without food. During that time, blood glucose (sugar) drops, and the body starts using stored fat for energy. That sounds helpful, but it also puts stress on the system.

When the person finally eats, it’s usually a very large meal, which can cause a big spike in blood glucose and make the body work harder to process it. Over time, this pattern can affect energy levels, metabolism, and even digestion.

Large meals can result in indigestion, bloating, and acid reflux (heartburn). Insulin spikes could occur, which works like a growth hormone, and can cause weight gain. Several people who try to lose weight wonder why nothing shifts despite consuming OMAD. This may be a contributing factor.

On the other hand, prolonged fasting like OMAD can eventually cause the body’s metabolism to transition to fat oxidation, making the body burn fat more efficiently.  If done consistently and if calories are controlled, this can lead to weight loss. 

G: Are there specific patient populations, such as those with diabetes, heart disease, or a history of eating disorders, for whom OMAD poses serious medical risks?

Dr. M: OMAD does pose risks for individuals, such as persons living with diabetes, by causing high blood glucose spikes following meals, and also in those with cardiovascular diseases, such as high blood pressure, where large meals can increase the heart’s workload and blood pressure.

Pregnant and breastfeeding moms are at risk of both caloric and micronutrient deficiencies, which can affect the infant’s growth and development. Young adults, particularly adolescents, have increased nutritional needs at this age; OMAD is inappropriate for them.

Persons with chronic illnesses such as peptic ulcer disease and chronic kidney disease also need to be wary of such eating patterns or otherwise risk exacerbation of their symptoms.

OMAD can also trigger unhealthy eating habits in those with a prior history of eating disorders.

G: What does the current clinical research say about the long-term safety of extreme caloric restriction patterns like OMAD?

Dr. M: Some observational studies point to increased low-density cholesterol (bad cholesterol) and impaired glucose tolerance when large meals are consumed infrequently. The truth is, we don’t have strong long-term evidence that eating once a day is safe or better than other eating patterns. Most studies show that simpler approaches like eating within a 10–12 hour window give similar benefits without the stress of extreme restriction. So, OMAD is more of a trend than a medically recommended approach.

G: Have you personally seen patients come in with health complications linked to following the OMAD diet, and what were the warning signs?

Dr. M: Yes, I’ve seen some patients who were following very restrictive eating patterns, including something like one meal a day. When I encountered some of them, they were following this pattern because they wanted to lose weight, but despite this were not achieving their goal.

I remember that some of them complained of persistent headaches, tiredness, or dizziness, and tended to overeat when they finally ate that one meal. Others presented with poor blood glucose control, and I had to explain the importance of regular, timed meals in achieving optimal blood glucose levels. There is also the risk of losing muscle rather than just fat while on restrictive diets like OMAD because the body will switch at some point to burning muscle. This can cause redundant skin on the upper arms and buttocks.

G: What advice would you give to someone who is determined to try OMAD? What medical checks or precautions should they take first?

Dr. M: If someone really wants to try it, I wouldn’t just say ‘don’t do it’,  I would educate them on the risks and recommend healthier, sustainable options.

The baseline, however, is to rule out any chronic medical conditions by getting basic health checks such as blood sugar, cholesterol, and blood pressure. If your physician diagnoses any of these conditions, ensure you get medical clearance before commencing OMAD.

I would advise that their one meal or any meal at all is very balanced, with their plate having enough protein, vegetables, and whole food options. They can adopt the ‘Healthy Eating Plate’ in which half of the plate is vegetables, a quarter of the plate contains healthy, whole carbohydrates or whole grains, while the remaining ¼ would be healthy protein.

Most importantly, everyone should listen to their body constantly. If they feel weak, dizzy, or unwell, they should stop and seek medical advice.

Lola Oyewole-Udabor

Glazia: Is it realistically possible to meet all of your daily macro and micronutrient requirements within a single meal, and what does that meal need to look like?

Lola Oyewole~Udabor: Personally, I do not believe so. The body needs the right balance of vitamins, fibre, protein, and nutrients for it to function efficiently. The only way to succeed at this will be through a highly functional meal plan, and that would require guidance from a nutritionist. A single meal with all the nutrients eaten in one sitting might work for one person and not the other, as bodies do not respond the same way, and activity levels could vary.

G: How does eating once a day affect metabolism, muscle retention, and the body’s ability to absorb nutrients compared to conventional eating patterns?

LO-U: OMAD can enhance insulin sensitivity and promote fat-burning by maintaining a fasted state for 23 hours. However, if calorie intake is too low, it may result in a slower resting metabolism. Retaining muscle can also be challenging. Furthermore, nutrient absorption is not as effective when meals are not spaced out, as consuming large quantities of food can overwhelm the digestive system, leading to competition for absorption pathways among essential minerals like calcium and iron.

G: Social media has made OMAD very popular for weight loss as a nutrition expert, do you think it is an effective and sustainable strategy, or largely hype?

LO-U: Social media hypes whatever sells and a lot of people are looking for quick fixes without consulting experts. The main dangers with OMAD include muscle loss, possible nutrient deficiencies, and a slowdown in metabolism, as the body finds it struggles to absorb a full day’s worth of protein and vitamins in just one hour. 

G: What are the most common nutritional deficiencies you see in people who adopt very restrictive meal-timing diets like OMAD?

LO-U: Research indicates that the primary deficiencies associated with OMAD are protein and fiber, as it can be challenging to consume and absorb sufficient amounts in a single meal to avoid muscle loss and digestive problems. Additionally, lots of people experience imbalances in electrolytes – sodium, potassium and magnesium, as the body tends to eliminate these during extended fasting periods, resulting in fatigue or a feeling of “brain fog.”

G: If someone wants to lose weight healthily, what evidence-based alternatives would you recommend over OMAD?

LO-U: I would recommend a more balanced approach, such as the 8 or 10 hour eating window, typically provides comparable advantages while ensuring better long-term success and nutritional adequacy. The Mediterranean diet which focuses on wholesome eating  – healthy fats, lean protein and high-fibre plant foods is also highly ranked as it focuses on nourishment instead of just fasting. Generally, when it comes to weightloss, changing or improving eating habits should be the focus and these changes will become visible. Eating to nourish should always be the goal, this approach makes a difference.  I would also add that factors like sleep, stress and exercise also contribute to how one looks or feels.