'); 9 Differences - 16:8 Intermittent fasting vs OMAD

9 Differences – 16:8 Intermittent fasting vs OMAD


Intermittent fasting has made a buzz in the market because of its capability to deliver impressive body transformations without hustling at the gym.

OMAD (One Meal A Day) is just an extreme case of intermittent fasting that is quite intense and difficult. As the name suggests, you are allowed to have only one meal while the OMAD diet pattern.

The difference between the intermittent fasting and OMAD resides within the fasting window. While most common intermittent fasting happens to be 16:8 style fasting when a person fasts for 16 hours and eat within the 8-hours window. On the other hand, OMAD is an extreme version of intermittent fasting when you are allowed to rely on a single big meal. You eat only one meal in a day that comprises all the caloric and nutritional requirements. 

Apart from the difference in the fasting window, there are differences like the effects on production of Growth, weight loss, mental clarity, etc.

Let’s get to understand the 9 differences between conventional 16:8 intermittent fasting and OMAD. 

16:8 Intermittent fasting vs OMAD

Fasting has been scientifically proven to be highly beneficial for the body, but all types of fasting are not equal. There are different styles of fasting available and we are going to discuss the two most common fasting styles. let’s get the discussion started.

1# Duration: 

It’s the most obvious and a key difference between conventional intermittent fasting and OMAD. 

OMAD is the extreme case of intermittent fasting when you feed your body only a single meal a day. Frankly, it can be quite difficult to deal with the food craving. 

We usually don’t recomend newbies to hop directly on one meal a day diet patter, here is how the progression works:

  • Start with 16:8 intermittent fasting for a few weeks 
  • Progress towards 20:4 intermittent fasting, that means you fast for 20 hours and eat within the 4 hours of the window. 
  • After a few weeks of getting comfortable with the 20:4 fasting, its time to switch yourself to One Meal A Day.

The transition period of OMAD can be quite challenging Most people to take at least 2 weeks to get their bodies to adapt to the OMAD lifestyle. 

2# Testosterone levels

Testosterone is a powerful male hormone, which is responsible for major functions in the male body, like sex drive, muscle building capacity, bone density, mood swings, etc.

But as you age, your body’s natural ability to produce testosterone depletes which results in weak bones, stress, low energy levels, low libidos. 

Fasting has been proven very effective in maintaining healthy levels of testosterone levels. 

16:8 intermittent fasting and OMAD (one meal a day) influence testosterone levels in a different manner. 

16:8 intermittent fasting on testosterone levels: 

A study conducted on the effects of short term fasting with a group of non-obese men. It found some promising results, the study stated LH (luteinizing hormone – a testosterone precursor hormone) rises up to 67% and overall testosterone increased by 180%.

So basically, a simple 16 hours fasting can help you retain your muscle mass and keep your body healthy. 

OMAD on testosterone levels: 

If you are impressed with the changed on testosterone levels by 16:8 intermittent fasting then slow down and check what changed OMAD brought to the testosterone levels. 

Study conducted at the Department of Internal Medicine, University of Virginia Medical School, Charlottesville found breathtaking improvement in GH production. 

Another research found, just a 24-hour fast can elevate your growth hormone levels by up to 800% in men.

OMAD pushes your body into fight mode that results in high testosterone levels and energy levels. This huge boost in testosterone levels helps in preserving muscle mass and utilizing stored fat as a primary fuel source. 


3# Mental clarity

You can experience dizziness and jittery at the beginning of fasting but soon your body will adapt to the new diet pattern. 

Superior mental clarity is one of the biggest benefits of any kind of fasting. But why do you experience superior mental performance in the absence of food? The answer lies in the evolution of mankind. 

Primal humans were primarily dependent on the hunting and in case of no-hunt, they had to stay hungry. So, the body developed itself to perform better when it’s hungry, brain signals the production of performance-enhancing growth hormones that helped in pushing the body for superior performance by having more energy, better concentration and improved cognitive function while hunting. 

So you can say, fasting awakens the body’s killer instinct which improves mental clarity and performance. 

There is another reason why you experience better energy levels while fasting, its because of the production of ketones. Ketones are chemicals made in your liver. You produce them when you don’t have enough insulin in your body to turn sugar (or glucose) into energy. You need another source, so your body uses fat instead. Your liver turns this fat into ketones, a type of acid, and sends them into your bloodstream.  

Mental performance while 16:8 intermittent fasting

After 16-hours of fasting, you definitely get to see better mental clarity and allows you to perform better in the peak working hours. 

Higher testosterone levels also allow you to feel more energized. 

Breaking your fast during lunch period might make you feel sluggish and sleepy because of the sudden spike in insulin levels. You should always break your fast with the combination of complex carbohydrates, fats, and protein. 

Mental performance while OMAD

OMAD can take your mental clarity to another level. I had been a big fan of 16:8 fasting for a long time but when I first experienced the benefits of OMAD then I never went back to 8 hours of eating window. 

After a week of OMAD I was able to experience an Extreme boost in testosterone levels and mental clarity. There was no chance of being sluggish after lunch period and I was able to deliver the best performance for the whole day.  

OMAD also incorporates the utilization of stored body fat as a primary source of fuel which allows the production of “Ketones”, these ketones act as a fuel to your brain cells and make you feel energetic. 


4# Difficulty

No doubt, fasting is difficult. But what’s more difficult? 

16:8 intermittent fasting is considerably easier than OMAD. 

Midnight – 4amSLEEP
4am – 8amSLEEP
8am – NoonFASTING
8pm – MidnightFASTING

This is a typical eating window of 16:8 intermittent fasting.

While the 16-hours of the fasting period, a person sleeps for 8-hours and just skipping a regular breakfast can help you rip the benefits of fasting. 

OMAD is the extreme case of intermittent fasting and its fairly difficult to incorporate as well. But, good things come to those who are willing to pay for it. 

5# Weight loss

We all know about the weight loss effects of intermittent fasting, but how exactly it happens? 

Eating 3-5 meals a day keeps your blood sugar level up and your body glycogen levels are always full.

Intermittent fasting breaks the continuous supply of energy through glycogen, hence it forces the body to use stored fat into energy which leads to fat loss

Fat loss with 16:8 fasting

Most of the food is digested and its energy is utilized within 12 hours of consuming it. Fasting for 16-hours allows you those extra 4 hours when your body uses fats as a source of fuel. Additionally, the boost in testosterone levels also elevates the metabolic stress which burns calories at a faster pace

Consuming healthy meals within that 8 hours of feeding window is found to have many positive effects on the overall body composition. 

Fat loss while OMAD

OMAD take your fat loss journey to another level, here is how it cut down your fat. 

  • Its highly unlikely that you will be able to eat a 3-4 regular meal within that one meal plan, this results in a reduction in calorie consumption. 
  • Spike in testosterone levels also leads to the preservation of precious muscle mass and also keeps the metabolism high. 
  • OMAD triggers the production of ketones which guide the body to use stored fat as a source of energy. 

In short OMAD works much better for fat loss. 


6# Calorie calculation

Intermittent fasting is good but you still need to stay within a caloric deficit to experience a healthy fat loss. 

On the other hand, One meal a day gives you a free hand to eat any number of calories. Still, it’s recommended to take those calories through healthy food sources. 

OMAD is proven to be a true diet for people who believe in a minimalistic lifestyle. 


7# Discipline and willpower

Are you someone who is looking to improve the discipline and willpower? Triumph over hunger should be your first target then. 

Fasting is the best way to improve self-discipline and setting yourself up for the spiritual path. 

Discipline and willpower for 16:8 intermittent fasting

Skipping breakfast for a 16-hour fast doest really challenges your willpower and you will be able to do it quite easily. 

Don’t really expect to develop superior willpower with the conventional 16:8 fasting. 

Discipline and willpower for OMAD

One meal al day is something the majority of the yogi and holy saints follow. No doubt it will seriously challenge your willpower in an initial 3-4 weeks. 

If you’re interested in challenging your willpower and getting out of your comfort zone, eating one meal a day will provide for some good practice.

8# Strength training

Best overall exercise equipment for home

“will I lose muscle?”, “Can I workout while fasting?” “can I lift heavy while fasting?”, This is one of the most common questions that many people ask before following any kind of fasting. Let’s find out the answer in both types of fasting. 

Strength training while 16:8 intermittent fasting

Its totally recommended to strength train while doing 16-hours fasting. There are many different ways to train while fasting. 

You can either strength train at the end of the fasting window and break your fast with a healthy protein-rich diet. 

Or, you can just adjust your strength training session within that 8-hours of the feeding window. Training within the feeding window will help in feeding optimum pre-workout and post-workout nutrition. 

Strength training while OMAD

In the initial days of OMAD, it’s highly recommended to avoid any kind of regressive training until your body adapts to the new diet regime. 

Once you get yourself comfortable then it’s suggested starting with moderate workout sessions. 


9# Money and time

Looking to save money? OMAD can be the best solution, at the end of the month I was able to save more than 1000 bucks. 

Eating all day is unhealthy and expensive too. Following One meal a day is an inexpensive way to stay lean all season. 


Intermittent fasting isn’t a ‘starvation’ diet, it’s a healthy lifestyle.

OMAD is a clear winner in comparison to 16:8 fasting but beginners should start with low-intensity 16-hours fast before advancing towards the one meal a day plan. 

Eating one meal can be quite difficult in the initial days but don’t worry, the body will adapt to it within a few weeks.

OMAD & Intermittent Fasting FAQ

Does OMAD slow down your metabolism?

Several studies have shown no negative effect on metabolism, but if you are still concerned about the slowing down metabolic rate then its better to do OMAD 5 days a week and take a break of 2 days for re-feeding just to allow your body some break.
You should never allow yourself to eat crappy food even in re-feeding days. Eat a highly nutritious diet with proper macro nutrition for optimum results.

Why am I gaining weight on intermittent fasting?

Intermittent fasting is not a magic solution to weight loss, you are gaining weight because you are eating more calories than you burn.
Many people have been using fasting as a solution to crappy food, which leads to negative effects on body composition.
Track your calories and eat 200-300 fewer calories than the calories you burn.

What intermittent fasting is best for weight loss?

The longer you fast, they faster you shred that stored fat. From my point of view, OMAD is the best way to lose weight.
Follow this for faster results:
– Increase the low-intensity cardio duration while in a fasted state by simply walking more or cycling at low intensity.
– Eat optimum protein and moderate carbs.
– Don’t skip Fats, they play a vital role in regulating many hormones.

How long should you do OMAD?

There is not specific study on the optimum duration of OMAD. I suggest you to follow OMAD as long as you see some positive results.
After every 8 weeks, give your body a break for 2 weeks by following only 16-hours fast.

How To Start OMAD Diet?

One should never jump directly to the One Meal A Day diet pattern, instead its always recommended to start with 16 hours fast, then progress to the 18 hours and slowly progress towards 23 hours fast and 1 hour feeding. A average guy will take 2 months to comfortably progress into OMAD.
What if you directly direct on OMAD? Your body might react negatively because of sudden shock.

Thanks for reading. Questions welcomed in the comments as always. 

This site contains affiliate links as well as general health and fitness information. Please read my Medical Disclaimer and Writing Disclaimer for more information.     

Harsh Chauhan

Hi there, I'm Harsh, personal trainer and chief editor at Alphamale.co. I started this blog with the intention to tap on every question that has been unanswered for many years. With an experience of more than a decade, my goal is to transform the lives of millions of our readers by offering authentic fitness knowledge.

Recent Posts