Written by Garett Reid | NSCA, CSCS, CISSN, M.S.E.S.S
Fact checked by Andrew Lenau, ISSA CPT & Sports Nutritionist
FACT CHECKED
The OMAD diet is one of the newer diets to hit the mainstream and has generated a lot of hype. OMAD stands for “One Meal A Day,” and at its core, it’s really just a form of intermittent fasting, except you are limited to eating just once per day.
If we could only eat one meal per day, it would be the lunch buffet from 11-3, but I’m sure that’s bending the rules a little. Like all fad diets, it has also stirred up conversation in the athletic community about whether OMAD is good for muscle building or athletic performance.
And with high-level athletes like Rhonda Rousey and Hershel Walker promoting it, people are curious. Therefore we wanted to dig into this extreme diet and see what it’s all about. More importantly, we will see if you can go to the weight room following OMAD and succeed.
This article will go over:
- What is OMAD?
- What can you eat on OMAD?
- Can you build muscle with OMAD?
- Can you get stronger with OMAD?
- OMAD and weight loss
Let’s see what all the fuss is about and if it’s optimal for weight lifting and muscle gain. To be clear, this article is coming from the perspective of putting on muscle. While we will address other common questions regarding the OMAD diet, our main goal is to see if you should try this when wanting to build muscle.
What Is the OMAD Diet?
OMAD is actually quite simple in its design in that it allows you to just eat one meal per day. OMAD is essentially run as intermittent fasting with a 23:1 fast:feed ratio. In other words, you have one hour to eat all of your calories. While this hour of eating is 100% up to you, most people will choose to eat from late afternoon to early evening (3-7).
Other than that, there are no other restrictions on what food you can or can not eat. Similarly to other forms of intermittent fasting, OMAD isn’t really so much a diet but rather an eating pattern. However, it’s obviously recommended that you stick to healthy foods and concentrate on still getting your macros.
What Can You Eat On OMAD?
As mentioned above, you can technically eat whatever you want on OMAD. However, as most people are following OMAD for health concerns, they will tend to eat healthier foods. In fact, it’s not uncommon to combine OMAD with another diet such as OMAD and paleo or OMAD and carnivore. Or you can just combine OMAD with flexible dieting. Again, OMAD is not concerned about what you can eat but rather when you eat it.
Is the OMAD Diet Good For Building Muscle?
While this article will review some of the other proposed benefits of following OMAD, it has one primary purpose. Can you build muscle on OMAD? Are OMAD and weightlifting a good combination, and should you try it? In other words, can you pack on slabs of muscle while eating once a day?
Surprisingly, upon research, many articles are strongly confident that not only can you build muscle on OMAD, they claim OMAD is good for muscle growth. We’re going to have to kindly disagree, and our reasoning is quite simple for two simple reasons.
As far nutrition is concerned, these two reasons just so happen to be the two most important variables for muscle growth:
- Eating a caloric surplus
- Protein intake.
1) IT'S VERY DIFFICULT TO CONSUME ENOUGH CALORIES ON OMAD:
Surprisingly, many lifters actually have issues eating enough calories to promote muscle growth, even with a full day of eating allowed. Now let’s cut the usual 16 hours of feeding time down to 1 hour and see how well those same people do with getting in their calories (calories with the right macros that is). Yea, not going to happen.
As mentioned above, being in a caloric surplus is the first rule to follow when you are gaining muscle. It’s not uncommon for average guys to need to consume 2,500+ calories in a day, and that’s on the way lower end. When you are on one meal a day, you need to eat all those calories in just one hour. You can definitely get it done, but it won’t be the most fun.
Even still, when we talk about eating a lot of calories, ideally, these are mainly with “clean foods .” As far as OMAD is concerned, the problem with eating clean foods is they are not calorically dense. This means you need to eat a ton of volume to get all of your calories in within an hour if you are eating healthy. You could go the easier way and eat “unclean” foods, but then you are sacrificing healthy eating to get in a caloric surplus.
The bottom line is that OMAD is not designed for people to eat many calories, which is exactly what you need when building muscle.
2) IT'S IMPOSSIBLE TO OPTIMIZE PROTEIN INTAKE ON OMAD:
In addition to not eating enough calories, it would be extremely difficult to eat enough protein, even if it all came from protein powder; you’re talking about 8+ scoops!! Unfortunately (at least for OMAD), protein has the highest satiety and fills you up fast. This makes it extremely difficult to get in all of your protein in only an hour. For 200g of protein, you would need to eat more than 1.5lb of steak or 8-10 chicken breasts! And that’s just for your protein!
Now that you ate all of your protein, you still need to get in all of your other calories and nutrients. Being that you’re so full from the protein, you’d likely need to resort to the aforementioned processed foods which are not good.
Another thing to consider is that even if you somehow managed to get in all of your protein, it would be far from an optimal manner. In order to optimize your protein utilization, you should spread out your total protein intake into 4-5 feedings throughout the day. This is because your body is able to better utilize protein in smaller servings of around 20-40g. While the whole “your body can only utilize X amount of protein per serving” is exaggerated, eating your entire daily protein intake at once is definitely not ideal.
Further, you are stuck with a conundrum when it comes to training. You have three choices when eating one meal a day:
- Train after being fasted for 23 hours so that you can eat your post-meal directly after.
- Train after your meal, meaning you then have 23 hours where your body will receive no nutrition for recovery.
- Train somewhere in the middle of your fast, meaning you have a substantial time of no nutrition before and after training.
None of the above scenarios are good for muscle growth, let alone optimal. While some may argue “it’s possible”, this is far from being “good” for muscle growth, especially when there are better ways to do it.
Is OMAD Good For Fat Loss?
One of the main reasons OMAD is used is for fat loss. Compared to gaining muscle mass, OMAD for fat loss would be a much more reasonable suggestion. However, similar to other forms of intermittent fasting, its effectiveness simply comes from the fact you are limited in the amount of time you have to eat, and thus calories you can consume. While only having an hour to eat isn’t great for eating a surplus for muscle growth, it does help in eating less food. Not much of a secret but not allowing yourself to eat all day will result in fewer calories consumed. Boom…weight loss.
What Are The Benefits Of OMAD?
To be honest, we don’t see any one benefit that OMAD offers that can’t be found on other diets. Further, the other diets, even other forms of fasting, seem to be much more realistic and plausible. That being said, we’ll go over some of the more commonly reported benefits of OMAD and why we don’t feel they apply to gaining muscle mass.
1. OMAD Can Save You Time
One of the more commonly reported benefits of OMAD is that it saves you time because you’re not bogged down with that annoying task of eating. Seriously. We suppose that you would save time, but we would also argue that if you’re too busy to eat, you probably have some serious issues with time management. While skipping breakfast makes sense to us in this aspect, a diet is about health, not saving time. Sure, no one wants to spend needless hours cooking, but there are plenty of time-efficient ways to prepare healthy meals. Regardless, time saved by OMAD has little to do with muscle gain.
2. OMAD Lets You Eat Whatever You Want
We touched on this above, but again, “eating whatever you want” does not seem like it’s setting you up with healthy eating habits unless you plan on eating once a day for the rest of your life. Still, there’s no way to eat sufficient calories and protein to optimize muscle growth which ruins the point of doing OMAD for muscle growth (obviously). Maybe that is a benefit for others but not for those wanting to gain muscle. In fact, one short-term study found that eating once a day led to higher blood pressure, likely due to eating unprocessed foods as they were allowed to eat whatever they wanted. To be fair, they also saw fat reduction and a decrease in cortisol.
3. OMAD Can Fix Hormonal Issues
One of the most significant benefits of OMAD is its effect on hormone issues, specifically its improvement to insulin sensitivity. However, this benefit isn’t specific to OMAD, as studies have shown improved insulin sensitivity can occur in many forms of fasting. Still, that’s definitely a plus, especially in the modern world where diabetes is through the roof.
However, as the above study showed a decrease in cortisol levels, most studies show that fasting causes an increase in cortisol due to the elevated stress put on the body. In fact, a recent meta-analysis found that a long-term low calorie diet is less stressful on the body when compared to short-term fasting by way of measuring cortisol levels.
4. OMAD Promotes Autophagy
One of the loudest claims of proponents of OMAD is that it promotes a process known as autophagy. To keep things simple, autophagy is a process by which your body identifies old cells and disposes of them; basically a recycling system. Heightened levels of autophagy are reported to keep us feeling and looking young and can also mitigate disorders such as Alzheimer’s, cancer, and Parkinsons’. And to be fair, fasting does do this really well.
However, fasting isn’t the only way we can induce autophagy. In fact, there are two extremely powerful catalysts related to this article; regular exercise and intense exercise. Studies have shown that being consistent with activity long-term can elevate autophagy levels significantly.
In the same vein, a positive relationship between autophagy and exercise intensity has also been discovered. However, it’s more than that and quite interesting. This study took well-trained athletes and created groups that differed in exercise intensity and in feeding and fasted states. They found that the most significant factor for inducing autophagy was exercise intensity, stating that exercise intensity seems to be “the most effective strategy to activate autophagy”.
That being said, admittedly, this is a much more nuanced subject that is way beyond the scope of this article. In addition, there do seem to be some genuine benefits connected to fasting, OMAD, and longevity that should be explored further in its own right. Therefore, if you are interested in these benefits, we strongly recommend you to check out other resources.
OMAD’s Greatest Downfall
Unfortunately, when it comes to OMAD, we can’t really see any reason you would want to do it if you are into bodybuilding. Sure, only allowing yourself to eat one hour per day might help you lose weight, but cutting your feeding time down to 30 minutes would help you lose even more weight. And you can see where this leads. Greatly restricting your time to eat isn’t really fixing any poor diet habits. In fact, OMAD says nothing about fixing your diet, as it what types of foods you are consuming. Amazingly, most blogs that promote OMAD actually use the fact that you can eat whatever you want as a benefit of OMAD. That's not healthy.
In contrast, we feel that this is OMAD’s greatest failure as it’s not addressing the root issue of many people’s failure with diets. To be clear, we do not feel this way about all forms of intermittent fasting. Also, if you are using fasting for other health benefits, we understand that (even if we may disagree a bit). However, we do not feel that greatly limiting the time to eat is a healthy way to solve overeating and poor food choices; let alone it could lead to more significant eating disorders.
OMAD And Weightlifting: The Bottom Line
When it comes to OMAD and weightlifting, our opinion is simple. No.
While OMAD might be able to help with weight loss, it is definitely not a diet made for weightlifting and muscle gain. If you read pro-OMAD articles, you will notice that they try really hard to explain why it’s possible not to lose muscle on OMAD. However, this is not gaining muscle, nor is it optimal to gain muscle. However, this isn’t new. Many new diets hit the scene and pretend to be a cure-all:
- You can gain muscle!
- You can lose weight!
- You can have more energy!
- You can save time!
- You can cure cancer!
Unfortunately, the vast majority of these are incredibly misleading. Many diets may have some genuine benefits, but they then decide to go overboard with their claims and act as if they are optimal for everything. They aren’t.
Unfortunately, with OMAD, we personally can not identify one benefit that makes it optimal for putting on muscle. While it may work for some lifestyles or individuals, try something else if you want to put on mass and build strength.
Related: Everything To Know About Intermittent Fasting For Women
Garett Reid
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