Intermittent Fasting: A Simple Guide to Fasting on Keto and Its Benefits

Intermittent fasting (IF) has quickly become one of the hottest health and fitness trends and for good reason. People are losing weight and improving their health significantly by incorporating it into their lives.

Because we are big proponents of the keto diet we have huge interest in intermittent fasting as it can help your body enter a state of ketosis much quicker.

A number of studies have shown that intermittent fasting can have very powerful (positive) effects on your body and brain. Some believe it may also help you to live longer.

This guide is meant to help you understand intermittent fasting, its benefits, and how you can incorporate it into your life.


What Is Intermittent Fasting?

Okay, not to sound all stodgy but I want to use the right words here.

Intermittent fasting is an eating pattern that cycles between fasting (not eating) and eating.

Didn’t that sound stodgy? Bleh.

Intermittent fasting is not about which foods that you eat. That is dependent on the diet (or no diet) that you are following.

Intermittent fasting isn’t a diet, it’s an eating pattern.

There are several different intermittent fasting methods and they all split the day or week into different eating and fasting periods.

Unless you’re the one person on the planet that eats while they sleep, then you put yourself through a fasting period already.

Intermittent fasting can be as simple as extending the period of time you don’t eat. Maybe you decide to skip breakfast and wait until lunch before having your first set of calories.

That is intermittent fasting.

If you decided to skip breakfast, ate lunch at Noon and the last time you ate prior to that was 8 pm the night before, then you’ve fasted for 16 hours.

Great job!

See, intermittent fasting, technically, isn’t that hard to do. What gets people caught up is a routine. Lots of people are used to waking up and eating breakfast.

Knocking yourself out of that routine can be tough, especially if you cave in at the first sign of hunger. However, hunger isn’t usually an issue with basic intermittent fasting.

Once your body gets used to your eating pattern then you’ll find that intermittent fasting is a walk in the park.

What Can You Consume During the Fasting Period?

This is a good question to ask. No food is allowed during the fasting period, but you can drink water, coffee, tea and other non-caloric beverages. There are arguments on whether or not you can drink bulletproof coffee while fasting so I’ll leave that up to you.

Some people like to take a tablespoon of Apple Cider Vinegar to curb any hunger. I like to drink flavored seltzer water since it tricks my mind into thinking I’m filling up with a sweet drink.

There are some forms of fasting that allow small amounts of low-calories foods but for the purpose of this article, we’ll continue to talk about the ones that don’t allow you to eat until the eating period begins.

Intermittent Fasting Benefits

You probably know that humans have already been fasting for thousands of years. There wasn’t always a grocery store on every corner where you could grab some food.

You had to hunt or gather your food and if you couldn’t do either, then you just didn’t eat.

Many religions also incorporate fasting in their practices.

Do you like to eat when you’re sick? Probably not. Humans and animals alike tend not to eat when they are sick (this is fasting).

There is absolutely nothing unnatural about fasting and our bodies are designed to handle extended periods of not eating.

This all sounds great but what are the benefits of fasting? While there are many, let’s cover the major ones.

Reduction in Blood Sugar and Insulin Levels

Studies show that when you fast, you can begin to see a drastic reduction in blood sugar and insulin levels. This is one of the big pluses of the keto diet.

When your body doesn’t have glucose to use as fuel it must begin to turn to other sources of energy. In the case of the ketogenic diet, this fuel source is ketones.

When you aren’t constantly pumping your body full of carbs then your body has no need to produce insulin so your insulin levels drop. When there is less sugar in your body then your blood sugar levels become more controlled.

Weight Loss

Many people that look into IF do so to lose weight.

Intermittent fasting is a very simple way to restrict your calories and burn fat. This is why people that want to get into ketosis quickly, do some form of intermittent fasting to speed up the process.

The faster you can enter ketosis, the fast your body can start burning fat for fuel.

Live Longer

This one is hard to gauge but there are studies showing that rats live longer on an IF routine.

This suggests that you can live longer just as easily as you can lose weight with intermittent fasting. Even if it isn’t the case where you live longer, the benefits are all great signs of a healthy life.

Simplifies Life

Instead of having to eat 4+ times a day you can condense your meals into 1-3. This means less worrying about what you’re going to eat and when.

When you don’t have to focus on what your next meal is going to be you can focus more on other things.

I guess you can call intermittent fasting a life hack.

I want to dive a bit deeper into intermittent fasting and weight loss so let’s do that.

Intermittent Fasting & Weight Loss

As mentioned before, weight loss is the most common reason that people try IF.

By eating fewer meals, intermittent fasting can lead to a lower daily calorie intake but that’s assuming you eat less and not try to cram what you usually eat into an 8-hour session.

The basis of any weight loss program is that you burn more calories than you consume so if you burn 1500 calories a day just by sitting and an intermittent fasting routine leads you to only eat 1200 calories in a day, then you’ll lose some weight.

But the greater effect that intermittent fasting has is one your hormones. IF lowers insulin levels and increases human growth hormone levels. More importantly, it increases the release of the fat burning hormone norepinephrine (noradrenaline).

Because of these small changes in hormones, IF can lead to an increase in metabolic rates.

Eat less and burn more. That flips the calorie equation on its head.

All of this sounds great so what are the different types of IF and which one should you choose?

Types of Intermittent Fasting

There are several different methods of IF and to cover all of them would take more words than you want to read. Instead, let’s take a look at the more popular ones.

  • The 16:8 Method: You fast for 16 hours and eat during an 8-hour period (not 8 hours straight). For example, you eat from 10am – 6pm and fast until 10am the next day.
  • Eat-Stop-Eat: 2x a week you do a 24-hour fast. Usually this means that you don’t eat anything for dinner one day until the next day when dinner time arrives.
  • The 5:2 Diet: Pick 2 days of the week and only consume 500-600 calories on those days.

The most popular method is the the 16:8 method popularized by Martin Berkhan. I prefer this method because it’s the easiest to stick with and requires no thinking. I know I can eat at 11 am and I need to finish eating by 7 pm every day.


After a couple of days, it just becomes a natural way of eating. Often I’ll look at the clock and see that it’s 2 pm and I haven’t eaten anything yet!

Sometimes I’ll eat at 3 pm and then just not be hungry anymore so I’ll skip dinner and just wait until 11 am the next day so, in reality, I’m fasting for 20+ hours sometimes without even a second thought of eating.

Should You Try Intermittent Fasting?

Unfortunately, intermittent fasting isn’t for everyone.

If you are underweight or have a history of eating disorder then you shouldn’t try intermittent fasting without consulting a health professional first. It can even be harmful if this is the case with you.

Intermittent fasting isn’t something that you need to do to lose weight. It is simply a lifestyle choice that people make that can improve their health.

Clean eating, physical activity and plenty of sleep are still the staples of living a healthy life.

There is no nutrition solution that will work for everybody. The best method of eating is the one that you can stick with forever.

Should Women Do Intermittent Fasting?

There is evidence that intermittent fasting doesn’t work for some women. In fact, it does the complete opposite and makes things worse!

There is a study that shows that intermittent fasting can improve insulin sensitivity in men, but made blood sugar control worse in women.

There are also plenty of stories of women who’ve had their periods stop completely when they started with IF and things went back to normal when they stopped.

Because of these reasons, women should be careful with IF. Ease yourself into it and if you experience any problems then stop doing it.

Intermittent Fasting Side Effects

The main side effect of IF is hunger. You are probably used to eating any time that you are hungry so holding off until a certain time will be weird initially.

If you’re familiar with the side effects of keto, then you’ll know about the additional side effects of intermittent fasting like feeling lethargic and a foggy brain.

These pass over time.

If you have a medical condition then it’s important that you consult with your doctor before trying IF. This especially holds true if you:

  • Have diabetes
  • Have problems with blood sugar regulation
  • Take medications
  • Have a history of eating disorders
  • Have low blood pressure
  • Are a female that is trying to conceive
  • Are pregnant or breastfeeding

With all of that being said there is nothing dangerous about not eating for a bit of time if you are healthy overall.