Intermittent fasting (IF) or time-restricted eating refers to consuming all your calories in a certain window period, followed by a period of fasting.
There are many different variations of fasting but they all boil down to one specific element: allowing your body to enter a fasted state and spend some time there.
Generally, the body requires about 12 hours to completely digest your food intake and enter a fasted state.
Food consumption vs. Fasted State
The body’s response to food consumption is much different than when in a fasted state.
When the body receives food (specifically carbs), it signals a rise in insulin which helps to metabolize it, either using it as energy or storing it into the fat cells. This process halts stored fat burning and utilizes the exogenous energy (food) as fuel instead.
Fasted on the other hand, the body’s need for insulin is low, thus elevation of opposing hormones such as growth hormone and glucagon occurs.
Furthermore, in this state the body begins mobilizing and utilizing stored body fat as fuel.
Note* Even if you are not following an intermittent fasting regimen, you can take advantage of this fat burning process by avoiding carbohydrates immediately after you wake.
When you wake, insulin is low and your body is in a fat burning state. By consuming a low-carb breakfast, your body will continue using fats for fuel, maintaining a more stable blood sugar level.
There are many people who still believe the saying “Breakfast is the most important meal of the day” or “You need a big breakfast (and lots of carbs) to fuel your day”.
Unfortunately this is awful advice and literally the opposite of what generally happens.
Skipping breakfast all together (fasting) or even just avoiding carbohydrates until later in the day will provide great stable energy, mental focus and clarity.
Benefits of IF:
- Protects neurons and promotes autophagy (the process in which your body cleans out damaged cells and generates new ones). (1)
- Reduces risks of various diseases. (2) , (3)
- Promotes fat loss.
- Many mental benefits – lowers anxiety, depression and improves social functioning. (4)
- Improves insulin sensitivity and increases testosterone levels in men.
When in a fasted state, here are the rules to remain there:
- Water is vital and should be consumed in abundance (half your body weight in ounces is a good daily target)
- No canned drinks, pops, shakes or fruit juices. They contain calories – mostly sugars at that.
- Tea or coffee works. (adding 50 calories or under worth of fats – coconut oil in coffee, splash of cream, etc. is fine).
- Alcohol is a hell-nah. Not only is alcohol full of empty calories, it’s a toxic compound forcing your body to place primary focus on metabolizing and eliminating it ASAP. I mean, everything can be passable once in a while, just don’t make it a habit. If you do consume some alcohol, make sure to drink plenty of water afterwards.
Who’s it for and How to do IF
Although there are many different methods to IF, I like to stick to the basics.
Generally, the easiest method to successfully follow through for most, while greatly reap its benefits is the 16/8 IF.
The 16/8 Intermittent Fasting diet refers to eating all your calories within an 8 hour window and fasting the remaining 16 hours daily.
Most men do extremely well with this approach and see great fat loss benefits, increased energy and higher testosterone levels.
You can organize it based on your own lifestyle, but typically most common path is skipping breakfast (they still had energy, mind you) and begin eating at noon or 1:00 pm, finishing last meal at 8:00 or 9:00 pm.
Although may be hard at first (until body and mind adjusts), this method works great for energy, mental focus as well as fat loss.
Women generally tend to do better with a slightly longer eating window – a 14/10 IF works well.
14/10 refers to eating your calories within a 10 hour window, while fasting the rest of the 14 hours.
If you have a bigger amount of weight to lose, starting with the 16/8 IF method would be more suitable. This will give your body more time in a fasted state, thus potentially burn more fat as fuel.
Note* Some women experience increased irritability and mood swings from possible hormonal disruption. (5)
Since we are all slightly different, experiment various methods on your own body and gauge what works best for you.
The longer you keep your body in a fasted state, the better it will become at using fat as a primary fuel source.
Fast and Feast
This method is exactly as the title would imply. Fast for 18 or 20 hours and feast once or twice within 4 or 6 hours span.
This approach is most suitable for people that already have some experience with IF or fasting in general.
I recommend easing yourself into this approach by starting with the standard 16/8 IF and moving up if you feel suited.
The most convenient aspect of following IF is that as long as it’s mostly healthy eating, calorie counting will not be necessary.
“But don’t I need to eat 6-8 small meals per day to keep my metabolism going?”
No, this is yet another myth and inaccurate advice at that.
There is no difference in energy expenditure from eating one or 7 meals per day as long as calories remain the same. (6)
In fact, being in a fasted state allows your body to convert fuel sources from carbohydrates to fats since there is no readily available energy being ingested.
As for the individuals scared to lose muscle mass, it will not happen, relax.
It would take strenuous high intensity workouts and serious malnutrition for that to happen. Even then, there’s the beauty of muscle memory which will help regain the lost lean tissue incredibly fast.
Final Words
Intermittent Fasting can be an effective tool for fat loss, improving insulin sensitivity, mental clarity and increased testosterone.
From my experience as a trainer, it is best suited for those that have a bigger amount of fat to lose and/or poor insulin sensitivity from overeating carbohydrates previously.
However, anyone can reap at least some benefits from incorporating intermittent fasting as part of a healthy diet plan for a leaner and stronger body.
