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7-day OMAD protocol

I Tried the One Meal a Day (OMAD) Diet – Here’s My Experience

If you have ever looked into intermittent fasting then you have likely come across the most extreme version, called the One Meal a Day diet, or OMAD for short.

The protocol is really simple in theory but is on the extreme end of the different intermittent fasting protocols you can follow. The idea is to eat within a one-hour time window and fast for the remaining 23-hours each day.

In principle, it’s straight forward but for most of us in practice certainly not easy.

I can see the appeal to some hardcore intermittent fasting fanatics, I was keen to understand if the science supports the protocol and whether I could do it for 7-days, and importantly would it work for me.

With staying at home more now my energy requirement is lower than usual so I was concerned about weight gain as a wander around my condo. So, I thought why not give the OMAD diet a try for the next 7-days.

This post is a bit longer than usual. Stick with it though and discover my experience of following the OMAD diet protocol for 7-days straight. I reveal my daily measurements for my weight (kg), sleep (hours), activity levels (steps), food and beverage intake, and how I felt each day.

Fasting eating protocol

Are you crazy? OMAD during lock-down!

This is probably the number one question I have been asked this week.

Surely staying at home and trying a restrictive eating pattern is the last thing you want to do.

I disagree, let me tell you why.

The thing is, within just a few days of being in lock-down in Malaysia due to the Coronavirus, I was finding it way too easy to eat more than I am used to. In fact, within the first few days, I could feel, and see on my scales, that I was putting on weight.

Considering the prospect of then 2-weeks, but now it’s a minimum of 4-weeks staying at home and likely over-consuming, I didn’t want to be back at 70 kilograms and 28% body fat, like I was in July 2019!

So, this is why I thought why not spin this around and turn this is to a challenge.

That is exactly what I did.

What’s my purpose of following a 7-day OMAD?

I wanted to prefix this challenge with what I am aiming to get out of this.

  • Some weight loss – Reducing a few KGs would be nice
  • Focus & productivity – What impact does OMAD have on work
  • Mental challenge – Simply put, can I do it in these challenging times!

I am not intending to follow OMAD indefinitely, instead, I am keen to see how physically and mentally how I respond to it.

It would be great to reduce body fat over the next 7 days of course, but this is only part of the aim.

With this in mind, I know that I will be in a calorie deficit this week. I won’t be counting calories, I won’t be doing any exercise (but will note my daily step count).

A secondary benefit will be to experience the impact of focus and productivity, or at least to see how this plays out.

My Interest in the OMAD fasting protocol

I have been experimenting with the Intermittent Fasting (IF) protocol for the best part of the last 6 months. My fascination first started from wanting a healthy eating program that didn’t involve counting each morsel of food or liquid I consumed.

This led me to try the 18/6 fasting protocol back in July 2019 for the first time in what I coined my fat belly challenge (you can check it out here). I ended up easily losing 5 kilos in 3 months, a little shy of my goal of 6 kilos, but importantly I discovered that the Intermittent fasting protocol suited me.

Since the fat belly challenge, I have continued with this protocol. Most weeks I do a 24-hour fast typically from Sunday night to Monday, and each month I try to do a 40-hour fast (if you haven’t tried this I really recommend giving it a go, it’s really not as bad as it sounds).

My Intermittent Fasting Schedule

Benefits of eating just once a day?

Most of us are so used to eating what and when we like that the prospect of eating just one meal per day is daunting.

There are many benefits to skipping meals and restricting the time in the day that you eat. I know, because of last year when I gave intermittent fasting a try for the first time I experienced weight loss (fat loss too) and better clarity (at times).

last year when I gave intermittent fasting a try for the first time I experienced weight loss (fat loss too) and better clarity (at times)

A side benefit that is less talked about is the easier your life becomes.

When I wake up I am not thinking of what to eat, preparing breakfast, and then tidying it up.

I just drink water and grab a black coffee and I am ready to go.

Main benefits of OMAD

  • Weight loss – It goes without saying that consuming just one meal per day means that you’re most likely in a calorie deficit for the day. Extended periods of following the OMAD protocol may have trade-offs with reduced metabolism, I talk about this later on. However, in the short-term, it’s inevitable that you will lose some weight, both water, and fat.
  • Increased focus – The tiredness and brain fog that follows most lunchtime meals is a thing of the past simply because you’re not consuming a lunchtime meal. When I fasted for 40-hours I was super focused and productive on the second day.
  • No food restriction and calorie counting – Most diet protocols consist of fairly rigid food selection and typically counting all your calories. With the OMAD protocol there is no calorie counting or having to hit percentages of each macro.

What does the science say about fasting?

Now fasting helps with weight management and improving focus is through a couple of ways.

Firstly by keeping insulin levels in a better range and avoiding the spikes seen when eating multiple times a day, especially when consuming high sugary foods. Lower levels of insulin during the day means you can burn more fat.

Secondly, a process that’s called autophagy, which is when the body cleans our damaged cells to help in regenerating newer cells.

The process of autophagy is encouraged as it removes toxic proteins, recycling other useful cellular material for other processes,

Autophagy is receiving a lot of attention for the role it may play in preventing or treating cancer, too.Healthline

Basically, do it the right way, fasting can be healthy for you!

What are the “rules” of the OMAD protocol?

Recently, I have discussed the OMAD protocol with a few friends I have noticed there are some different interpretations of how this works.

Basically what’s allowed, and what isn’t.

Keen to get it right, I delved into a few great articles that give a breakdown of how to successfully complete an OMAD diet.

The common questions around OMAD that I was looking for answers too.

Are you really meant to get ALL your calories from one meal?

This is the main question most people ask when discussing OMAD, one I had with a few of my friends too!

I for one would really struggle to try to consume ALL my calories in one meal.

From what I have read on Diet Doctor you’re not necessarily trying to consume all your calories in the one-meal. Instead, you try and consume most of them.

DietDoctor suggests looking to consume a daily calorie intake of 1,800 kcal per day when on OMAD.

Based on their research, DietDoctor suggests looking to consume a daily calorie intake of 1,800 kcal per day when on OMAD. I was most likely going to be consuming less than this for three reasons.

  1. My body weight is 67 kg and so basal metabolic rate (BMR) is lower
  2. This week I will be more sedentary due to being in lockdown
  3. I am looking to lose a little body weight

That said, during OMAD you don’t necessarily have to count calories.

I look into the number of calories to consume during OMAD next.

How many calories should I eat on OMAD?

I couldn’t find a resource that gives hard and fast rules on the exact number of calories to consume, of course, this will vary will body weight.

I am between 65-70kg most times and so my calorie intake will significantly differ from a guy weighing 100kg.

According to the Harris-Benedict Formula that’s commonly used by nutritionists, this helps work out how many calories above your basal metabolic rate you need each day.

First you need your BMI, I used this calculator to get my BMI of 1532.

Next, I used the Harris-Benedict Formula with the sedentary (or no exercise) metric of 1.2 to arrive at my daily intake of 1838.

If I wanted to consume ALL my daily calories then I would need to consume 1838 Kcal during my one-hour eating window.

Out of interest, I checked the “total burn” data on my Oura ring to see how many calories in real life I used. Flicking through the data over the last few weeks I can see that my readings vary from 2,000 to 2,500 kcals per day, depending on the number of steps.

This correlates approximately with what the Harris-Benedict Formula came back with within a 10% margin of error.

..one of my goals is some weight loss this week. The healthy recommendation is to consume 500 per day less calories, which means my aim is to eat a minimum of 1300Kcal per day.

However, I am wanting to be in some calorie deficit as one of my goals is some weight loss this week. The healthy recommendation is to consume 500 per day fewer calories, which means my aim is to eat a minimum of 1300 Kcal per day.

How much to eat on OMAD

Can I drink coffee on OMAD?

In short yes, In fact, you can drink any calorie-free beverages such as water, and black coffee or tea at any time. It makes sense to avoid drinks that contain caffeine too close to bedtime though for obvious reasons.

I have been drinking 2-3 iced black coffees during the day, no later than 5 pm.

Can I drink zero calorie soft drinks?

No.

I struggled to find evidence to support no, but it’s thought that the sweet taste in such soft drinks could release some response from the pancreas in the form of insulin. If this happens the insulin could linger for a long time in the body trying to grab sugar that’s not there.

To follow a proper fasting protocol it makes sense to err on the side of caution and stick to water, black coffee or tea.

Will OMAD slow my metabolism?

If you’re following the protocol primarily for weight loss then a slowing metabolism is not what you want.

When you first start a calorie-restricted diet everyone experiences initial weight loss, mostly from less water retention.

However, experiencing chronic caloric restriction will start to lower your resting metabolic rate, which then makes longer-term weight loss tricky.

This is a concern for anyone trying OMAD for weight loss a big concern is whether OMAD will make you fat.

Consistent clinical experience shows that widening the fasting window can help improve these metabolic conditions.DietDoctor

Longer-term slowing of metabolism is the reason why intermittent fasting is preferred to just following very-low-calorie diets.

It’s also why alternate days fasting, the 5:2 diet (fasting for just 2 days each week), or doing the 16/8 (or 18/6) intermittent fasting approach is recommended (Healthline).

Possible side effects of OMAD

It’s VERY likely that you’re going to experience low energy levels and hunger pains at some point. The side effects we are talking about here, are the ones to be really concerned about and you need to watch out for.

Side effects like feeling unwell, extremely fatigued, dizzy, and nausea are not normal experiences when following OMAD.

If you experience any of these then stop and seek medical advice to check you are fine.

In most cases simply stopping the protocol will help, but if it’s still recommended to seek a medical opinion.

Crashed out asleep on the sofa - fatigued

Can OMAD be a healthy lifestyle choice?

This is the ultimate question really.

Past the practicalities of sustaining an OMAD diet, the question I think is more, should you?

Long periods following an OMAD diet is not considered the best approach. In fact, following any restricted calorie intake diet long-term is not recommended.

Instead, the advice is to switch up OMAD alongside either you’re normally eating pattern or even better to alternate with a less restrictive intermittent fasting protocol, like the 16/8.

This is the approach I am looking to adopt, as it will keep my metabolism on its toes making sure I don’t overeat and still enjoy many of the benefits of following an intermittent fasting protocol.

In my experience of doing OMAD for one-week, I found this okay but a bit too long, even though I got used to it by day 6.

Which is better OMAD or Intermittent fasting?

Intermittent fasting is without a doubt much easier than OMAD. I found following an intermittent fasting routine helped with trying OMAD, and so if you want to try OMAD I would try intermittent fasting first.

To answer this question it comes down to your goal.

If you’re looking for faster weight loss then OMAD did correctly can work better than intermittent fasting.

Otherwise, for health-benefits there is not much difference between the two meal protocols. Following a 16/8 intermittent schedule is easier and has similar health benefits.

I came across this excellent article of a guy who compared both of these meal timing protocols, check out Ryans OMAD vs Intermittent fasting article.

My Experience and OMAD Results for 7-days

Every day last week I measured my weight using my PICOOC Bluetooth weighing scales (you can find this on Amazon here) first thing in the morning after peeing.

I noted body weight and body fat percentage.

I tracked my total sleep time and activity level using the Oura ring (check out my review of it here) that I wear every day, this also tracks my activity level in terms of step count.

I took pictures of everything I ate during the feeding window that I kept between 6-7 pm each day so that I could eat with my family.

The other benefit was that I could enjoy my wife’s cooking too 😉

My assessment of hunger was purely subjective and noted during the day whenever I noticed any significant change.


Day One

  • Body Weight: 67kg
  • Fat Percentage: 26%
  • Total Sleep Time: 6 hours 30 minutes
  • Daily Steps: 4,973
  • Meals: 4 sausages, mash potato, vegetables (double the portion shown in the picture below)
  • Drinks: 2.4l water, 2 x black coffees, 1 x black tea, 1 x purple minoa drink, 1 x SuperGreen TONIK greens drink

OMAD Day 1

SUMMARY: My first day on OMAD and boy was I looking forward to my first and only meal of the day. The day went okay and mentally was set for this week’s challenge.

Day Two

  • Body Weight: 66.3kg
  • Fat Percentage: 24.9%
  • Total Sleep Time: 4 hours
  • Daily Steps: 4,750
  • Meals: 1/3 salmon, rice, egg, baked beans, cauliflower, spinach
  • Drinks: 2.4l water, 2 x black coffees, 2 x black tea, 1 x purple minoa drink, 1 x SuperGreen TONIK greens drink

OMAD Day 2

SUMMARY: I woke up already hungry, which is not a great start. In hindsight, I have to admit that my food choice the day before wasn’t the best. I should have eaten a little more protein and consume a bit more food. The main issue was the lack of sleep last night. I worked late on day one, which meant I struggled to get to sleep before 3 am. Lesson learnt, don’t work in the evenings!

Day Three

  • Body Weight: 65.9kg
  • Fat Percentage: 25.8%
  • Total Sleep Time: 7 hours 30 minutes
  • Daily Steps: 5,050
  • Meals: pasta, chicken, carots, spinach, yoghurt with berries, nuts and berries
  • Drinks: 3l water, 2 x black coffees, 2 x black tea, 1 x purple minoa drink, 1 x SuperGreen TONIK greens drink

OMAD Day 3

SUMMARY: Felt good today, no hunger when waking. I did feel hungry the afternoon though and really enjoyed my meal at 6pm. This didn’t affect my working schedule at all.

Day Four

  • Body Weight: 65.6kg
  • Fat Percentage: 25.7%
  • Total Sleep Time: 7 hours
  • Daily Steps: 6,167
  • Meals: chicken, rice, beans, carots, egg, tomato, fish
  • Drinks: 3l water, 3 x black coffees, 1 x black tea, 1 x purple minoa drink, 1 x SuperGreen TONIK greens drink

OMAD Day 4

SUMMARY: Morning I was fine but the afternoon I struggled with hunger a bit. The hungriest I have felt since starting OMAD. After eating I was fine though.

Day Five

  • Body Weight: 65.2kg
  • Fat Percentage: 25.6%
  • Total Sleep Time: 7 hours 47 minutes
  • Daily Steps: 6,167
  • Meals: salmon croquette, rice, vegetables, chicken soup, yoghurt and honey, nuts
  • Drinks: 2.4l water, 2 x black coffees, 1 x black tea, 1 x purple minoa drink, 1 x SuperGreen TONIK greens drink

OMAD Day 5

SUMMARY: Awful day today as I woke up feeling unwell (not coronavirus). My body was aching and had a sore throat, very tired. I spent the day in bed until I resurfaced at 5 pm in time for my meal of the day.

Day Six

  • Body Weight: 65.4kg
  • Fat Percentage: 25.7%
  • Total Sleep Time: 7 hours 1 minute
  • Daily Steps: 6,167
  • Meals: 1/2 salmon, pasta, sun-dried tomotoes, carots, cauliflower, yoghurt with honey, nuts and berries
  • Drinks: 2.4l water, 2 x black coffees, 2 x black tea, 1 x purple minoa drink, 1 x SuperGreen TONIK greens drink

OMAD Day 6

SUMMARY: Felt much better today and back to 90% health. Little hunger today and had a productive day doing a little work and spending time with the family.

Day Seven

  • Body Weight: 65kg
  • Fat Percentage: 25.5%
  • Total Sleep Time: 7 hours 46 minutes
  • Daily Steps: 6,720
  • Meals: fish and chips, lots of roasted vegetables, 4 slices of pizza, yoghurt with honey
  • Drinks: 3l water, 3 x black coffees, 1 x black tea, 1 x SuperGreen TONIK greens drink

OMAD Day 7

SUMMARY: Felt amazing today, very little hunger and enjoyed spending time with the family. Gave myself a treat on my last meal in having 4 slices of pizza (tasted super good).

What I learnt and results from doing OMAD for one-week

I am not going to lie to you, following OMAD on consecutive days is not easy. Depending on your consumption pattern you may find OMAD very hard to follow.

But, it does get easier thanks mostly to training your hunger hormones (Leptin and Ghrelin) to fire less often.

This week was far easier than when I first tried a fasting eating pattern many years ago, when I lived as a monk during my stay in a monastery in Thailand, trying to cleanse my body and soul of too much partying.

Spoiler alert, it didn’t work!

Let’s focus on mentally how I found last week. All in all pretty good.

I was pleased that my willpower and discipline was strong enough to complete the task. I have written how being too comfortable is a productivity killer before, so I like to mix it up and challenge myself now and then.

One thing is for sure when you haven’t eaten for 23 hours you really do savor your first mouthful. My wife commented that this way I would find all her meals super tasty! She doesn’t have to worry there, her cooking is really nice and much more inspiring than my pasta sauces.

…when you haven’t eaten for 23 hours you really do savour your first mouthful.

This was my longest period of time eating just once a day.

I found it physically easier to handle after the first 2-3 days. Days that I felt tired were related to the previous night’s sleep, so on day two I found difficult staying awake in the evening and was noticeably tired during the morning.

My 5 hacks to surviving OMAD

Anyone keen to give OMAD a try should first ensure they are healthy enough too firstly. If you’re unsure then have a chat with your medical doctor to be sure.

If you’re good to go through, this is how to make following OMAD easier:

  1. Don’t jump straight into OMAD. I would recommend trying a less strict intermittent fasting protocol, like the 16/8, and see how you get on.
  2. Make your one meal really count. Don’t reach for the fast-food that’s unhealthy for you. When you haven’t eaten for 23 hours most food is going to taste great, so ensure you get a healthy selection of macros and micronutrients
  3. Drink plenty of water. This has two benefits, of course, there is the much-needed hydration but also drinking water can make you feel fuller.
  4. Drink a greens drink. Seriously, I am not just plugging my SuperGreen TONIK here (well okay a little bit), having a greens powder supplement means you can get all, or most, of your micronutrients in one easy drink.
  5. It’s not a big deal. OMAD is a mental challenge, quite a big one for some people who really enjoy their food. Speaking to people about doing this and most people are amazed, believing it’s such a challenge. Believe me, it’s not with the right mindset.

Is The OMAD Diet for me?

After 7 days of OMADFollowing the OMAD diet on consecutive days for a week was initially challenging, I am not going to lie to you. Even when your energy expenditure is low, it still takes a degree of mental toughness to stick too.

But, if you can stick to it (and why not?) then you start to experience the benefits after a few days. For me, I felt good after 6 days.

My OMAD physical results included a flatter stomach, check out the side profile!

I just need a six-pack and pecks, I know!

Mentally I experienced better focus and productivity, it was hard to ignore that I felt great.

Only on day five when I was completely out of action, I could work well, and actually, it made each day really easy. No stopping for lunch breaks and feeling tired in the afternoons.

I never intended to follow the OMAD intermittent protocol indefinitely, mostly from a practical viewpoint as you can get the benefits of fasting following a less restrictive protocol.

I already incorporate one-day on OMAD each week, well most weeks. It’s perfect when you want to counteract periods of overconsumption, which is the main reason I do it on Sunday evening to Monday.

Familiarity with intermittent fasting certainly helps you to get into the pattern quicker. So, I would certainly not recommend jumping straight into OMAD on consecutive days, but follow the 16/8 or 18/6 first.

The benefits of OMAD are very appealing, for the reasons outlined above. But doing back to back OMAD days is not needed to enjoy the benefits. So, why put yourself through it!

From today I will be following the Intermittent Fasting scheduled outlined by DietDoctor. Tuesday and Thursday will be OMAD protocol days, with the rest of the week following an 18/6 intermittent fasting protocol. Sometimes though, I will grab a hearty breakfast, as, after all, I am only human!

It hopefully goes without saying but the information on this page is not a substitute for direct, individual medical treatment or advice. It is the responsibility of you and your healthcare providers to make all decisions regarding your health.
Adam Author

About the LifeHacker Guy

Hi, I'm Adam the founder of the LifeHacker Guy.

I have a First Class Honours degree in Sports Science from Brighton University, specialising in exercise physiology and nutrition. In my youth I was a competitive Triathlete and long-distance runner placing top 10 in most triathlon races I completed.

Since suffering from Chronic Fatigue Syndrome, I moved into web development, after a couple of years I then moved onto developing a number of online businesses. I've recently taken a sabbatical and I'm now looking to make big changes in my life, hopefully this may resonate with you - join me in my journey!

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