How Much Weight Can You Lose On One Meal A Day? (Realistically)

You can lose around 1.4 kg (3.09 pounds) in 11 days on the OMAD (One Meal A Day) diet, according to a 2022 study from the Department of Endocrinology and Metabolism at Amsterdam University Medical Centers. The study also suggests that you could potentially shed around 4 kg (8.8 pounds) in 30 days, assuming the rate of weight loss remains consistent. This is slightly at odds with the CDC’s recommendation, which advocates for a gradual, steady weight loss of about 1 to 2 pounds per week for long-term success.

The CDC emphasizes that maintaining a healthy weight isn’t about adhering to a specific diet or program. Instead, it requires a lifestyle that includes healthy eating patterns, regular physical activity, and stress management. Factors like sleep, age, genetics, diseases, medications, and environment can also impact weight management.

Contrastingly, anecdotal evidence, such as a video by YouTuber Lauren, shows that she lost 12 pounds in just 5 days on the OMAD diet. Lauren combined low-carb and low-calorie meals, targeting around 1,200 calories per day, and included some physical exercise in her routine. It’s important to note, however, that individual results can vary widely.

how much weight loss on OMAD diet

What factors determine how much weight one can lose with one meal a day?

Factors affecting weight loss on one meal a day include diet adherence, physical activity, age, sex, medications, behavioral and pharmacological responses, and surgical interventions.

  • Diet adherence: According to a 2009 study from the University of Alabama at Birmingham, dietary adherence is strongly associated with rates of weight loss and is negatively affected by extreme caloric restriction. High adherence to one meal-a-day diet could potentially result in faster weight loss, but extreme caloric restriction could make it harder to stick to the diet, thus affecting results.
  • Physical activity: According to a 2018 study published in Progress in Cardiovascular Diseases Journal by researchers from East Carolina University, Texas A&M University, and Louisiana State University, physical activity and exercise training can facilitate weight loss by creating a negative energy balance, but they are generally inadequate for clinically significant weight loss without caloric restriction. Eating one meal a day (OMAD) coupled with regular physical activity could amplify weight loss effects by boosting metabolism and increasing calorie deficit.
  • Gender: A 1988 study by P.A. Connor-Greene from Clemson University highlighted that women are more likely to adopt extreme weight loss measures, such as self-induced vomiting or laxatives. Interestingly, these societal pressures to be slender could steer women towards the one-meal-a-day (OMAD) eating approach. So, if you’re seeing more women giving OMAD a shot, this study offers some context.
  • Age: Based on a 2014 study from Duke University published in Obesity (Silver Spring), older adults (60+) had better initial and sustained weight loss over 3 years. If you’re considering the One Meal A Day (OMAD) approach, this suggests that age could be a game-changer, with older folks possibly shedding more pounds more effectively.
  • Specific medications: According to a study by N J Ahmed and colleagues from the Department of Clinical Pharmacy, College of Pharmacy, Prince Sattam Bin Abdulaziz University, published in Pharmazie in October 2022, medications like risperidone, adalimumab, and pregabalin commonly lead to weight gain. If you’re on medications known to cause weight gain, sticking to just one meal a day (OMAD) for weight loss might be less effective or may require additional strategies to see results.
  • Behavioral responses: The study “Metabolic and behavioral compensatory responses to exercise interventions: barriers to weight loss” from Queensland University of Technology in 2007, led by Neil A King, suggests that behavioral responses can either aid or counteract weight loss efforts. When it comes to eating one meal a day (OMAD), individual behavioral compensations like deliberately increased snack intake could potentially negate the caloric deficit aimed for, leading to lower-than-expected weight loss.

Other factors affecting weight loss on one meal a day include pharmacological interventions, surgical interventions, genetic makeup, neurohormonal mechanisms, metabolic efficiency, tissue capacities, non-exercise thermogenesis, thermogenic food responses, and gut microbiome.

How much weight can you realistically shed in a month with the OMAD diet?

The OMAD (One Meal A Day) diet could lead to a weight loss of approximately 1.4 kg (about 3.1 pounds) in 11 days, as per a study published in Frontiers in Physiology in January 2022 by researchers from Amsterdam University Medical Centers. This research, which included 11 participants with an average age of 31 and a BMI of 24, compared eucaloric feeding in three meals vs. one meal per day for 11 days. Not just weight, but fat mass also showed a significant reduction, lowering by 0.7 kg (about 1.5 pounds) on the OMAD diet compared to the three-meal-a-day plan.

The study attributes these changes to increased fatty acid oxidation during exercise and lower plasma glucose levels in the latter half of the day when on OMAD. This means the body becomes more efficient at using fat for energy, enhancing metabolic flexibility.

However, the effects of one meal a day diet can differ based on individual metabolic rates, exercise routines, and other lifestyle factors. The study only focused on “lean individuals,” so results might not be the same for people with different body compositions. Anyone with medical conditions that require regular food intake or those with a history of eating disorders should consult a healthcare provider before trying OMAD. This video explains what happens when you only eat one meal a day for 30 days.

How much weight can you lose on OMAD in 3 months?

Based on personal experiences and anecdotal evidence, you can expect to lose around 15 pounds in the first month of OMAD, with weight loss plateauing after initial rapid loss. Over 3 months, weight loss can range from 30 to 50 pounds, depending on factors like food choices and activity level. Consistency and stress management are key to maximizing weight loss on this diet.

How much weight can you expect to lose in the first week of OMAD?

The OMAD diet can lead to an average weight loss of 7-11 pounds during the first week. This is mainly because of water loss and a calorie deficit, according to a 2022 study in the journal “Nutrients” by Fatema Alkhulaifi and Charles Darkoh from the University of Texas Health Science Center.

It’s crucial to note that the initial OMAD weight loss might not be sustainable long-term, as the body adjusts to caloric intake. Also, people with certain conditions like diabetes, cardiovascular issues, or metabolic syndrome could experience adverse effects from this kind of extreme dieting pattern.

In situations where someone is already very lean or highly active, OMAD might not be the best choice as it can lead to muscle loss or nutrient deficiencies. The 2022 Nutrients study points out that poor meal timing and frequency are linked to metabolic syndrome, diabetes, and cardiovascular disease, which could make OMAD risky for people already facing these health challenges.

Now, Jeff Volek, a low-carb guru from Ohio State University, chimes in that cutting carbs and sodium makes your body ditch extra water weight. So when you hop on the scale after doing OMAD for a week, it looks like you’re shedding pounds like crazy. But, let’s keep it real, that’s temporary.

So, the short of it is, that you might see a pretty quick drop on the scale in the first week, but OMAD isn’t a one-size-fits-all solution and could be risky for some.

How much water weight can you lose on one meal a day?

The exact amount of water weight you can lose on the OMAD (One Meal A Day) diet is “unmeasurable,” according to Dr. Janelle McNeil-Masuka, an anesthesiologist from North Carolina, However, she notes that a healthy adult can lose between 600 to 800 mL of water per day. About 300 to 400 mL of this water loss occurs through diffusion via the skin, and a similar amount is lost through the respiratory tract. Techniques like carb loading and sodium manipulation, often used by bodybuilders, can also affect water weight. So, while you might lose some water weight on OMAD, the exact amount is hard to pin down.

How much weight can you drop if you combine OMAD with regular exercise?

Based on a 2022 study by Emma C E Meessen from Amsterdam University Medical Centers, switching to OMAD and exercising could help you lose around 1.43 kg in total body mass over 11 days. In contrast, the traditional three-meals-a-day routine led to only a 0.5 kg loss.

Dr. Nick Zyrowski, a founder of, recommends exercising right before breaking your fast for maximum fat-burning and hormonal benefits, boosting growth hormone by up to 1,300% in women and 2,000% in men. If you’re into cardio, Zyrowski advises doing it around your mealtime as it’s energy-intensive.

However, this might not work for everyone; the Amsterdam study focused on lean and healthy individuals. Plus, the study lasted only 11 days, so the long-term effects aren’t clear. If you’re pregnant, have medical conditions, or are new to fasting, consult your healthcare provider before diving in. With cardio, Zyrowski even suggests shifting from OMAD to a 16:8 fasting schedule for more intense sessions.

How much weight can you lose on OMAD if you also cut out sugary drinks?

Ditching sugary drinks while doing OMAD could significantly boost your weight loss. A study by Liwei Chen and others from the Center for Human Nutrition, Johns Hopkins Bloomberg School of Public Health, showed that cutting out just 100 kcal of liquid calories per day led to a weight loss of 0.25 kg in 6 months and 0.24 kg in 18 months. The study specifically found that reducing one serving per day of sugar-sweetened beverages was associated with a weight loss of 0.49 kg at 6 months and 0.65 kg at 18 months.

How much weight can you lose on OMAD if you’re overweight?

According to Dr. Grant Tinsley, an associate professor at Texas Tech University, following the OMAD (One Meal A Day) diet for 3 to 12 weeks can reduce your body weight by 3% to 9% and body fat by 3 to 5.5 kg. For an overweight male weighing 220 pounds, this translates to a weight loss of 6 to 20 pounds in that time frame. An overweight female weighing 180 pounds could lose between 5 to 16 pounds. Keep in mind that individual results can vary, and it’s crucial to consult a healthcare provider for personalized advice.

How does the timing of the meal in OMAD affect weight loss results?

The timing of your one meal in OMAD (One Meal A Day) can have various health implications and effects on weight loss results, according to a 2019 study published in the journal Nutrients by Antonio Paoli, Grant Tinsley, and others.

Eating your largest meal earlier in the day is generally associated with a lower risk of weight gain and better metabolic control. Skipping breakfast and eating late at night, on the other hand, can lead to metabolic inflexibility, low-grade inflammation, and impaired glucose homeostasis. The study also suggests that late eating is linked to an increased risk of obesity and coronary heart disease (CHD). So, if you’re on OMAD, it might be beneficial to have your one meal earlier in the day for optimal health outcomes.

How quickly can OMAD results be seen in photos?

You can typically start seeing visible results from one meal a day in as little as two to four weeks, depending on your starting body composition and how well you stick to the diet. This timeframe is often enough to notice changes in body fat percentage and muscle tone. For a more compelling narrative, taking a before and after picture at the start and then every week can help you track these changes visually.

Are OMAD before and after photos consistent with weight loss claims?

Yes, OMAD before and after photos often show significant weight loss, but it’s crucial to note that individual results can vary widely. Always consult scientific studies and healthcare providers for the most accurate and personalized advice on OMAD’s effectiveness for weight loss.

How much time does it take to lose weight on OMAD?

On the OMAD diet, the time it takes to lose weight can vary depending on individual factors like metabolism, activity level, and caloric intake. However, following the American Heart Association’s approach and setting SMART goals can typically result in noticeable weight loss within 3 to 12 weeks.

Michal Sieroslawski

Michal is a personal trainer and writer at Millennial Hawk. He holds a MSc in Sports and Exercise Science from the University of Central Lancashire. He is an exercise physiologist who enjoys learning about the latest trends in exercise and sports nutrition. Besides his passion for health and fitness, he loves cycling, exploring new hiking trails, and coaching youth soccer teams on weekends.

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