Ever wondered what would happen if you only ate one meal a day (the OMAD diet) for a full 30 days? Would you actually lose weight—or would your body go into starvation mode and hold on to fat? Could you lose muscle instead of fat? Or, worse, would your metabolism slow down, making it even harder to drop pounds in the future?
I’ve been following the OMAD diet (One Meal a Day) for almost two years, not every single day, but pretty consistently. And let me tell you—it’s worked really well for me. But I don’t want you to just take my word for it.
In this post, I’ll break down:
✅ What results you can expect if you eat only one meal a day for 30 days
✅ The science-backed pros and cons of OMAD
✅ How to do OMAD the right way (most people mess it up!)
✅ What studies actually say about OMAD and fat loss vs. muscle loss
So if you’re thinking about giving this a shot, keep reading because I’ll help you avoid the biggest mistakes people make when trying OMAD.
How to Do OMAD the Right Way (And What People Get Wrong)
Before we get into the results, let’s talk about how to actually do OMAD correctly. A lot of people think they’re doing one meal a day, but in reality, they’re following something closer to the Warrior Diet.
Here’s the difference:
✅ OMAD = A 23:1 fasting-to-feeding ratio (You fast for 23 hours, then eat one meal within a strict one-hour window at the same time every day.)
❌ The Warrior Diet = A 20:4 fasting-to-feeding ratio (You fast for 20 hours, then eat within a four-hour window.)
Many people make the mistake of stretching OMAD into an extended eating window—basically turning their “one meal” into a multi-hour buffet. This completely defeats the purpose because it prevents the hormonal benefits of fasting and can easily lead to overeating.
If you’re doing real OMAD, you need to commit to that one-hour eating window and spend the remaining 23 hours fasting.
Does OMAD Slow Your Metabolism? The Truth About “Starvation Mode”
One of the biggest myths about fasting and OMAD is that it slows your metabolism. Many people believe that if you don’t eat frequently, your body will hold onto fat and stop burning calories efficiently.
But science says otherwise.
A study called “Meal Frequency and Energy Balance” analyzed research on how meal frequency affects metabolism. The results? Eating more often had zero advantage for your metabolic rate.
What actually slows metabolism is long-term extreme calorie restriction, not meal timing. In fact, short-term fasting (less than 48 hours) has been shown to increase metabolism by 4-14% due to a rise in norepinephrine, which helps break down fat for energy.
So no, eating once a day won’t tank your metabolism—as long as you’re still getting enough calories and nutrients within that one meal.
Will You Lose Weight on OMAD diet? What the Studies Show
Now let’s get to the big question: Does OMAD actually help you lose weight?
A lot of people assume that eating smaller, more frequent meals speeds up weight loss because of the thermic effect of food (TEF)—the energy your body burns digesting food. But studies have repeatedly shown that meal frequency has no impact on weight loss when total calorie intake is the same.
One study compared two groups:
- Group 1 ate 3 meals per day
- Group 2 ate 6 meals per day
Both groups consumed the same total calories—and guess what? No difference in weight loss, fat loss, or hunger levels.
But what about OMAD specifically? There’s an actual study that compared:
- One group eating three meals per day
- One group eating just one meal per day (OMAD)
👉 After 6 months, both groups maintained their weight (since they were eating at maintenance calories).
👉 Hormonal responses were nearly identical, including ghrelin (the hunger hormone).
👉 The OMAD group reported more hunger during the day but also felt extremely full after their meal.
👉 Most importantly, the OMAD group lost more fat than the three-meal group.
Why? Probably because they naturally ate fewer calories and experienced more fat oxidation due to extended fasting periods.
Does OMAD diet Cause Muscle Loss?
This is another huge concern for people thinking about trying OMAD. After all, if you’re not eating protein throughout the day, won’t your body start breaking down muscle?
Not necessarily.
In the same OMAD study, researchers found no significant loss in muscle mass compared to the three-meal group.
Here’s why:
1. As long as you hit your protein goal within your meal, your body will preserve muscle.
2. Short-term fasting increases growth hormone levels, which helps protect muscle mass.
3. Studies show that fasting actually encourages the body to burn fat over muscle—especially when protein intake is sufficient.
So, as long as you’re eating enough protein and doing some strength training, you’re not going to lose muscle on OMAD.
Is OMAD diet Right for You?
Now, while OMAD has a lot of benefits, it’s not for everyone.
📌 It’s great for people who:
✅ Want to lose weight without obsessing over calories
✅ Feel good eating big meals rather than small ones throughout the day
✅ Have busy schedules and don’t want to think about food all day
📌 But it’s NOT ideal if you:
❌ Struggle with binge eating or intense hunger
❌ Have a physically demanding job that requires steady energy
❌ Have certain medical conditions (like diabetes) that require regular meals
One thing to note: In the OMAD study, the withdrawal rate was much higher than normal. About 28% of participants dropped out, suggesting that this diet isn’t sustainable for everyone.
Final Thoughts: What Can You Expect After 30 Days of OMAD diet?
If you stick to OMAD for 30 days, here’s what will likely happen:
✔️ You’ll lose weight & body fat (as long as you don’t overeat during your meal).
✔️ Your metabolism won’t slow down.
✔️ You’ll probably feel hungrier at first, but you’ll adapt over time.
✔️ You’ll experience more mental clarity and productivity.
At the end of the day, OMAD is a tool—and like any diet, it works best if it fits your lifestyle.
Have you tried OMAD before? Thinking about giving it a shot? Drop a comment below and share your experience!
Many people use fasting as a tool for self-discipline and better health—which is also key when trying to quit smoking. In fact, fasting and quitting smoking share a common challenge: breaking habits and cravings. If you’re working on improving your health in multiple ways, check out my Guide to Quitting Smoking and see how you can build a stronger, healthier you.
🚀 Share this with a friend who’s on a health journey too! 🔥💪 #OMAD #Fasting #QuitSmoking #WeightLoss
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