OMAD Diet: Eat One Meal A Day On This Extreme Form Of Intermittent Fasting

Functional Medicine Practitioner By William Cole, D.C., IFMCP
Functional Medicine Practitioner
Dr. Will Cole, D.C., IFMCP, is a leading functional medicine expert who specializes in clinically investigating underlying factors of chronic disease and customizing a functional medicine approach for thyroid issues, autoimmune conditions, hormonal imbalances, digestive disorders, and brain problems. Cole is also the bestselling author of Ketotarian and The Inflammation Spectrum.
OMAD Is The Biggest New Diet Trend For Decreasing Inflammation & Increasing Longevity

Image by Cameron Whitman / Stocksy

Saturated by a culture of excess food, overeating, and more of everything, people are exploring the concept that less can be more on many different levels. From Marie Kondo's method for helping us to get rid of all the clutter in our living spaces to the growing fascination with tiny homes, there is no doubt we are looking to simplify our lives.

Similarly, different time-restricted feeding (TRF) and intermittent fasting (IF) protocols are on trend. People are exploring different windows of time when they abstain from food or fast to improve their health—a sort of KonMari method for our body. While having its moment in pop culture right now, fasting is anything but new. Fasting has been used throughout human history for health and spiritual purposes. From an ancestral health perspective, always eating three meals a day (and snacking in between) wasn't what humans would have done throughout almost all of human history since they wouldn't have had constant access to the same amounts of food and would have regularly have had to endure periods of feast and famine. Fasting is part of our DNA. As a functional medicine practitioner, I have implemented intermittent fasting methods for years.

There are many ways to do intermittent fasting or time-restricted feeding, from the simple 8-6 plan (have your meals between 8 a.m. and 6 p.m.) to fasting-mimicking protocols like the modified two-day plan. This is where you eat normal clean meals for five days of the week (which days are up to you), and on the remaining two days, your intake will be restricted to no more than 700 calories. For more types of intermittent fasting, check out my article on the subject.

One special way to do time-restricted feeding (or intermittent fast) is something called OMAD. OMAD sounds super exotic, but it just stands for "one meal a day" (we love acronyms in wellness). An OMAD plan is what we call a 23:1 fasting-to-eating window, which means if you're following it, you'll fast for 23 hours and eat your food (and get all your calories) in one hour. Normally this involves waiting until dinner to break your OMAD fast, but ultimately it could be any meal with a 23:1 fast (it can technically be a 22:2 plan as well, if you eat your one meal's worth of food slowly). People typically do OMAD to improve their health, lose weight, or both.

So is OMAD something worth trying or better to avoid at all costs? Let's look at some things to consider.

The benefits of OMAD.

Deeper fasting benefits

Because OMAD is a more advanced way to intermittent fast, it is a chance to get in on all the research-backed benefits like:

Another key benefit of fasting techniques like OMAD is that it enhances nutritional ketosis, which has its own anti-inflammatory, fat-burning, and autophagy benefits. Because OMAD is a longer fast, it tends to maximize these benefits. Longer fasting windows give the body longer periods of time to enhance all the benefits of fasting—breaking the fast earlier slows those mechanisms.

For a full list of all the health benefits of fasting (with all the research hyperlinks for my fellow science nerds), read my article on the subject.

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Simplicity and convenience

OMAD super fans also love how there is very little planning involved with this way of fasting (because there is only one meal to plan for!). The only real meal planning involved with OMAD is when to break your fast, to make sure the meal you eat is enough calories and nutrients for the day.

Potential drawbacks of OMAD, and how to mitigate them.

You might not get enough food.

Because you going 23 hours without eating, it is important to get enough calories and nutrients in a day, particularly if someone is doing OMAD long term. The solution? Make sure you're eating enough calories and nutrients for your age, weight, and activity level. Also make sure your one big meal of the day is healthy, real food. Fasting protocols like OMAD are best paired with healthy foods. Don't try to fast your way out of a poor diet.

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It can contribute to an unhealthy relationship with food.

When you are talking about fasting, it inherently involves not eating food. For people who struggle with unhealthy relationships with foods, such as people who are or have in the past struggled with eating disorders like anorexia, orthorexia, or bulimia, OMAD can exacerbate pre-existing negative thoughts and habits. Many times, ways of eating or fasting can be an eating disorder disguised as a wellness practice. This is the antithesis of the intent of intermittent fasting. Fasting techniques like OMAD should be used as a way to love your body enough to take care of it, not a way to punish yourself by restricting food. You can't heal a body you hate. If OMAD or any other way of fasting is turning into an unhealthy obsession, if it is out of balance, causing a fear of food, stop. It is not right for you.

It can be trickier for women.

When it comes to intermittent fasting, women are usually more sensitive than men. This is, at least in part, due to the fact that women have more kisspeptin, which can create a greater sensitivity to fasting. If a woman's fasting is done too excessively for her body, it can cause her to throw off her cycle and shift her hormones. While more research needs to be done, it would make sense to logically conclude that this hormonal shift could affect metabolism and fertility too. The key here is to find a fasting amount that works for your body, and that amount looks different for different people. Check in with your body and how you feel when you try any type of fasting. For a full guide on how intermittent fasting can affect hormones, read my article on the subject.

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The way I OMAD.

I love doing OMAD some days, especially days I am traveling. Leveraging the benefits of fasting (such as increased ketones for your brain), OMAD is an easy way to mitigate the effects of flying (like airport food, jet lag, and air pressure changes, which can be hard on your digestion). I stay hydrated with lots of water, and I love to sip on Earl Grey tea during my OMAD fast because it enhances autophagy. I feel great on those days and enjoy it. Crazy, huh? I have seen countless patients over the years do well with OMAD days peppered throughout their life.

Do I OMAD every day? No. I do it when I feel like it. I do other intermittent fasting windows other days and eat three regular meals other days. There is a grace and lightness to my fasting, and there should be for anyone who wants to do fasting healthily and sustainably. OMAD or any other fasting shouldn't be stressful or miserable. The right way to fast is the type of fast that works for you and your body. Don't force something if it's not making you feel great.

If you are new to fasting, I suggest starting with more beginner variations of intermittent fasting. If you don't eat healthily, I suggest focusing on real foods and eating until you're satiated from those healthy foods for a while before you explore fasting. Get a good foundation first. Lower your sugar intake and focus on healthy fats, clean protein, and vegetables. This will be a great natural transition to fasting (here are some meal ideas). To this point, the more stable your blood sugar is and more you are fat-adapted, the more times fasting will happen naturally. When you are well-fed, nourished, and no longer hangry, OMAD (and other fasting windows) will happen effortlessly.

William Cole, D.C., IFMCP
William Cole, D.C., IFMCP
Will Cole, D.C., IFMCP, is a leading functional-medicine expert and a Doctor of Chiropractic. He...
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William Cole, D.C., IFMCP
William Cole, D.C., IFMCP
Will Cole, D.C., IFMCP, is a leading functional-medicine expert and a...
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