Intermittent Fasting: What You Should Know

Intermittent Fasting, Anabolic Fasting, 16:8, Intermittent Feasting, 5:2 (UK)… The names go on and on.  Over the past decade, fasting has become a nutrition lifestyle change for more and more people across the globe.  Many people love it.  Many people are scared to try it.  Here is the scientific research behind it:

The 5:2 Diet

A common trend you are seeing in the nutrition arena is intermittent fasting.  Intermittent fasting is the blanket term, but as you read above, there are a number of different terms used across the board.  This diet originally became popularized by the 5:2 diet which was developed in the UK.  The 5:2 diet is very simple to follow: you eat like you normally would for five days and for two days you eat 25% of the calories you regularly consume.  So let’s say you are eating around 2000 calories a day for 5 days, for two days you would consume around 500 calories.  The positive aspect of the 5:2 diet are that for the two days you are at an extremely low caloric intake you are increasing insulin sensitivity (the basis of a fasted diet protocol) therefore relying on fat stores as energy and thus, burning excess body fat.  The negative aspect is that the manual for the 5:2 diet says you can essentially eat whatever you want, putting no restrictions on what you are consuming– more simply put: you can eat whatever you want, just consider calories rather than nutritional value.  This poses a few issues because although I preach energy balance which is essentially exactly what the 5:2 diet principles rely on, it’s still important to consider quality of calories (remember the gut microbiome post?).  I am in no way disregarding the 5:2 diet as a great diet. It has research to back it up, it’s a great way for beginners to start, and the protocol is very simple.  Again, I can’t stress it enough, you have to figure out where you need to be calorie wise.  This will give you the basis of how the diet itself will succeed or fail.  If you are still struggling to grasp that concept, refer back to the energy balance post!

Intermittent Fasting, 16:8, Intermittent Feasting

The most common form of time restricted eating is termed intermittent fasting and/or 16:8.  This is very simple to follow and has the most relevant scholarly research available to date.  The concept is to fast for 16 hours, allowing for an 8 hour period in which all your calories are consumed.  As an individual, you can really manipulate this in a number of different ways just by using simple math.

  • First meal at 8 a.m.– Last meal at 4 p.m.
  • First meal at 11 a.m.– Last meal at 7 p.m.
  • First meal at 2 p.m.– Last meal at 10 p.m.
  • First meal at 7 p.m.– last meal at 3 a.m.

This diet is great in the sense that it allows the user to decide when their most optimal window for consuming their calories is.  Many people get frustrated though because if they workout in the morning, but follow a 12 pm.-8 p.m. window, they feel like they are dying from their morning workout until lunch. This poses some issues because then you are not only hungry, but you are more likely to overeat when your first meal comes. However, my best suggestion to these individuals is either purchase a BCAA supplement to curb your hunger and continue to synthesize proteins post-exercise– or adjust your eating schedule from 8 a.m.-4 p.m. There isn’t a strict “you have to eat at noon to 8 p.m. or you won’t lose fat.”  The beauty of this protocol is the ability to customize it.  Now in regards to your individual situation, some time frames may work better if you have children you need to feed or when you work.  However, it’s important to understand that physiologically, your body doesn’t start going into “panic mode” until around 84-90 hours of zero calories, so an extra hour or two without snacking probably won’t hurt you too bad. The common misconception of intermittent fasting is that it “has” to be 16:8 fast to feed ratio.  The reality of it is that you can do 14:10, 12:12, or even 22:2 (Intermittent Feasting). The most important part of intermittent fasting is the macronutrients you are consuming when you get to feed.  Don’t irrationally assume that you can now adopt the “see-food” diet (whatever you see, you eat) and not consider proper vitamins, minerals, and adequate macronutrient levels because you are eating a time-restricted diet.

Anabolic Fasting

Anabolic fasting is very similar to intermittent fasting and essentially follows the same “optimal” time restrictions (16:8).  However, with anabolic fasting, you are able to have a little bit more leniency when it comes to what you are consuming.  In fact, the best part about anabolic fasting is that it encompasses both intermittent fasting and 5:2, yet instead of eating rabbit sized meals on your “2” day, you’re able to eat the same amount of macronutrients, just in a “dirtier” fashion. Additionally, anabolic fasting is user friendly to those who may have children and/or a spouse that may not be on the same diet plan– your cheat days can be aligned with “Taco Tuesday” or a Friday night out to your local pub and pizzeria. Before you get too excited, the downside of anabolic fasting is that you must be very disciplined during your clean days and really make sure to track your macronutrients.  As I’ve mentioned a number of times before, it’s all about energy balance.  Once you know how many calories you should be taking in, the rest of your planning is pretty easy.

Here’s how it works: During your 5 days of clean eating, your macro breakdown will be 40% protein, 60% fat, with a little less than 25 total grams of carbohydrates per day.  These carbohydrates should be from the fat and protein sources, excluding dairy and grains.  Your 2 “cheat” days should be 15% protein, 25% fat, and 60% carbohydrates.  Now before you order a stuffed crust meat lovers pizza from your local Pizza Hut, these carbohydrates should be somewhat clean.  Not to say you can indulge in a few pieces of pizza or even a double cheeseburger, but lets refer back to the gut microbiome post.  Your nutrients should be useable fuel for your body not just simply calories for the sake of calories– don’t put gas into a diesel or you won’t be driving down the highway too long.  That being said, as I’ve mentioned before, you have to live your life and enjoy the foods you enjoy.  If you understand energy balance, you can still fit your favorite foods in and not completely fall off the rails about it.  I appreciate these rules because it’s a great reinforcer to say, “okay, I’ve got Sunday through Thursday that are going to be sparkling clean and at the end of the week on Friday and Saturday, I can enjoy a few beers with friends and enjoy a nice burger and be fine.”  All in all, anabolic fasting is an approach that is user friendly, easy to implement, and can provide leniency when it comes to a fat loss or muscle gain diet.


I want to emphasize that none of these diets are a magic pill.  You have to put some effort and discipline into them to have a positive effect.  Again, I know it’s getting old to hear it, but the biggest point to drive home is energy balance.  If you don’t understand it yet, refer back to the energy balance post– all of this information is on for free.  Regardless of timing, what you eat, and how much of it you eat, if you’re energy balance is in a positive state consistently, you’ll gain weight.  That’s just the science of it.  But if you are disciplined enough to consider energy balance, stick to one or more of these protocols, and be consistent with your DAILY actions, you’ll find the results you are looking for.

If you have questions or want to discuss what Arete can do for your performance, nutrition, or lifestyle, please feel free to email or text at any time! Follow us on all our social pages below! Have a great weekend!




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