Intermittent Fasting: Your Ultimate Guide

Some Background

IF, as it’s colloquially known, is a healthy alternative to the age-old and ill-fated diet. The fasting method has recently gained popularity amongst celebrities, athletes, and fitness enthusiasts alike.

While close to 99% of dieters regain the fat they lose on their health sabbatical, intermittent fasting provides a long term balanced and sustainable alternative.

Jimmy Kimmel attributed his 25-pound loss to the alternative diet plan, while Terry Crews swears by the regimen’s efficacy in helping him attain low body fat, and maintain muscle mass.

If you’re aiming for a lean physique while enjoying some of your favorite foods along the way, intermittent fasting may be for you.

Today, we will give you the tools you need to decide if intermittent fasting is worth a try. By providing you with background information, science, and personal experience that will help you make the right choice.

What is Intermittent Fasting?

Simply put intermittent fasting works by restricting the hours during which you can consume calories. The only exceptions to the restriction are coffee, tea, and water.

Although diet drinks have zero calories, I wouldn’t advise them since they may cause an insulin spike and stall your progress.

Even though there is no hard line for how many hours, or during which hours, you can restrict your “feeding window,” most people follow the 16/8 Method popularized by Lean Gains’ Martin Berkham.

The method advocates an eight hour feeding window, leaving you in a fasted state the other 16. Personally, I set my feeding window from noon to 8PM. I’ll explain my experience with that later on.

There are various other intermittent fasting methods; the 5:2 Diet, which restricts you to about 500 calories twice a week, and the Eat-Stop-Eat Method, during which you don’t eat anything from lunch or dinner one day, until the same meal the following day. It’s basically a 24 hour fast.

Setting a feeding window will help you stick to your dietary and fitness goals. Restricting yourself to certain hours gives you a clear set of directions.

This may eliminate any ambiguity that would usually lead to a disciplinary lapse. But it’s also important to actually understand the science behind intermittent fasting. Specifically, how it helps you achieve your goals.

On a Deeper Level

Fasting is not new or unnatural; humans have been doing it for millennia. We fast in a variety of situations; we do it instinctively when we’re sick, and wholeheartedly when observing religious holidays.

Our long fasting traditions show that our bodies are perfectly capable of handling prolonged periods without calories.

On a micro level, intermittent fasting works by triggering processes that operate when the body experiences prolonged starvation.

Simply put, when performing a task, your body uses more calories as a fuel source in a fasted state than in a fed state. This process can help you achieve fat loss and even muscle retention more rapidly.

Specifically, your body ensures proper function in a fasted state by adjusting hormone, gene, and other important cellular functions.

The key mechanism lies in increasing the activity of genes. As a result, this increases the number of calories the body uses and the amount of fat ultimately burned.

Effects of Intermittent Fasting on the Metabolism

A 2014 study1 from Universidade de São Paulo examining the impact of intermittent fasting on different parts of the metabolism found that other “recent experimental studies have elucidated some of the metabolic mechanisms involved with intermittent fasting.”

Specifically, “positive results have been reported on the impact of intermittent fasting for human health. Intermittent fasting is reported to improve the lipid profile; to decrease inflammatory responses, effectuated by changes in serum adipokine levels; and to change gene expressions related to inflammatory responses and other factors.”

Moreover, these studies show that intermittent fasting has a higher compliance rate amongst obese people than any other fat loss method. Intermittent fasting was also found to be associated with low oxidative stress.

The higher success rate amongst obese subjects reflects intermittent fasting’s efficacy as a fat loss mechanism. Since it’s easy to integrate and straightforward to follow, it’s no wonder that many shred the fat and reach their goals.

The simple schedule leaves people feeling less restricted and ensures not only follow through, but ultimate success.   

These observations have a scientific basis. Recently, a 22-day study2 of eight male and eight female subjects by the Pennington Biomedical Research Center in Baton Rouge, Louisiana, found that the alternate day fasting method of intermittent fasting led to a “2.5 ± 0.5% of their initial body and 4 ± 1% of their initial fat mass.” The study concluded that “alternate day fasting was feasible and led to increased fat oxidation.”

Muscle Gains

It’s worth noting that intermittent fasting has benefits besides fat loss. In fact, many bodybuilders have enjoyed muscle retention, and in some instances even muscle gain.

Their results are unsurprising as prolonged starvation has been found to lead to significant reductions in blood sugar. Insulin levels and as drastic increase in human growth hormone is also commonplace.

A study3 conducted by the Department of Internal Medicine at University of Virginia Medical School found “significant increases in discrete GH pulse frequency” following a five day fast.

Although I intended to concentrate on intermittent fasting’s effect on fat loss, muscle retention and even gain, it’s worth mentioning that there is some research linking the alternative eating pattern with longevity, improved metabolic health benefits, cancer prevention, and protection from Alzheimer’s disease.

Personal Experience

Speaking from personal experience, late night meals are often the worst, as they test your willpower the most. As the sun sets, so does my discipline. The later it gets, the more likely I am to eat unhealthy, too much, or in some decadent combination of the two. Something about eating when it’s dark out makes it harder to control myself in front of the fridge.

But when I restricted my last meal to 8PM, I no longer had a reason to be in front of the fridge or at the drive through. I prevented myself from making the wrong choices because I didn’t put them in front of me.

As anyone who has ever tried eating healthy and achieving the right lifestyle knows, it’s more of a mental struggle than a physical battle. Taking away any reason to have an unhealthy meal, small or big, is the surest way to overcome the struggle.

I set my eight-hour window between noon and 8PM as it was the easiest to start and stick with. A couple days in I realized that the 16/8 method was a reflection of how I already ate. After an early morning cup of coffee I don’t feel hungry well into noon. Plus my daily tasks conveniently keep my mind off of food.

Since I got off work around 6PM, I’d end up eating my dinner sometime between then and 8PM, a normal time to eat dinner, if there’s such a thing.

In my experience, the best part of intermittent fasting is its ease of adaptability and maintenance. Intermittent fasting is easy to start, worthwhile to maintain, and as the science suggests, rewarding of your efforts.




  1. When you say the only exceptions to the fast are coffee, tea, and water, can you add cream, butter or MCT oil to your coffee? These are all fats and therefore would not spike insulin. So can you have a “bullet coffee” which is coffee with butter and MCT oil in the AM (6-12) AM if your eating window is from 12-8 PM?

    1. Author

      Hey there, dietary fats influence insulin levels as well. Just not as much as carbs do.

      The benefits go beyond insulin resistance and sensitivity, however, and since butter and MCT oil are calorie dense, it’s best not to interfere with the fasting process in any way.

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