#139 The Best Intermittent Fasting Window For You

Siim Land (0:01)

You might think that intermittent fasting is simple, which it to a certain extent it is. If you just stop eating for a while, you're definitely fasting, and you're getting some of the benefits like autophagy, ketosis, fat loss, and mental clarity. However, whether or not it's aligned with your goals depends on how you fast, why you're doing it for, and what are your other life conditions in that particular moment.

There are many reasons to fast and there are many ways to fast. Some may say that too many of them, but I think that everything should be taken contextually, and it should be approached with based on the particular situation. It's the same as trying to go chop wood with a butcher's cleaver or a knife. I mean, you could do it, but it's just pretty stupid and unproductive.

In this episode of the Body Mind Empowerment Podcast, I'm going to talk about what's the ideal intermittent fasting window for you and your goals. I can't give you an exact template specifically tailored to you because I don't know you, but I can still give you the main principles and guidelines for structuring your fasting and eating routines. We're going to talk about the different types of fasting, what's time restricted eating, when you should eat, how to fast for fat loss, how to fast when working out, how to fast when doing shift work, how to fast on keto versus carbs, and how often to have extended fasts. So put aside your butchered cleaver because we're not going to need it right now. And let's start to chisel some optimal fasting protocols.

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You think that there isn't a lot of room for creativity or freedom when it comes to intermittent fasting. You fast for a certain period of time and just don't eat. However, there are a lot of different fasting windows out there. Here are the most common types of intermittent fasting. The 16 and 8 IF lean gains method. You fast for 16 hours and eat about 2 to 3 meals within 8 hours. It was popularized by Martin Birken, who combined it with bodybuilding and fat loss.

The Warrior diet. You fast for 20 hours and eat within 4 hours. Created by Ori Hoffmeckler, who tried to mimic the eating patterns of Roman warriors and legionnaires.

Oh, man. One meal a day. That's it. You just eat once a day, whenever it may be.

36 to 48 hour fasting. Shorter, extended fasts. I myself categorize them as moderate length fasts, because it's just two days and everyone can do it with no worries.

Extended fasts, two to five days and beyond. These are the longer fasts that most people do only every once in a while for primarily therapeutic reasons.

Alternative fasting. These are the every other day fasts, such as the fasting mimicking diet, 5-2 diet and I would even categorize Dr. Mercola's keto fast in here.

As you can see, there are many ways to fast and they can all work. What fasting routine is ideal for you depends on many things, such as your physical activity, metabolic condition, how much fat you have to lose, your lifestyle and your personal preference. There is no single eating window that suits everyone and it all has to be based on the individual, what they're trying to achieve and where they're at.

So in the rest of this episode, I'm going to help you find the ideal intermittent fasting window for you.

First of all, we have to cover what's the best time to eat. Although people tend to have their meals at different times, some time gaps are still healthier and better than others. Time restricted eating refers to confining your daily caloric intake within certain hours as to coincide with the circadian rhythms and light cycles of the sun. Daily intermittent fasting like OMAD or 16 and 8 should be actually categorized as time restricted eating because that's what you're essentially doing. You're restricting your feeding time. Intermittent fasting itself is just the act of intermittently cycling between eating and not eating, which can apply to both extended fasts as well as short term fasts. However, people have been doing intermittent fasting way before time restricted eating became a thing.

So the chronobiologists, they're just picking up on the trend and they're kind of stealing the term.

Research has shown that there are no significant differences between eating slightly earlier versus later in a day, as long as calories and the hours of fasting are matched. There are studies showing that eating breakfast and skipping dinner is healthier than the standard three meals a day. But comparing two meals a day, either breakfast and lunch or lunch and dinner shows no difference. One study in May 2019 found that eating from 8 a.m. to 2 p.m. versus eating from 8 a.m. to 8 p.m. improved blood glucose control, lipid profile and autophagy genes. However, that's compared to a non fasting group eating between 8 a.m. and 8 p.m. Of course, early time restricted eating is better because it's actually going into a fasted state versus someone who is eating between the hours of 8 a.m. and 8 p.m. Is it never actually going into a fully fasted state? Furthermore, this study was done on 11 overweight individuals over the course of just four days. An 8 hour time restricted eating window between 8 10 a.m. to 6 p.m. has also been shown to reduce blood pressure, lower body fatness and improve cholesterol profile. Another study in April 2019, a few months earlier, found that a 9 hour eating window from 8 a.m. to 5 p.m. versus 12 to 9 p.m. both of them had the same results in terms of health and body composition. So the most important variable is eating less often and within a shorter time frame wherein you activate autophagy and suppress insulin. You can eat whenever you like during the day as long as you stick to a few of these guidelines. First, wait a few hours after waking up before eating. Cortisol the stress hormone is the highest early in the morning. Usually people say that cortisol is bad, which is true to a certain extent. Too much cortisol throughout the day can be problematic, but that morning spike in cortisol is actually very beneficial. It increases your alertness, kickstarts this circadian rhythm, promotes fat mobilization, promotes ketosis and sets you off for the day. You don't really want to be eating with elevated cortisol because it makes it easier to store the food as fat. Instead, it would be always better to wait at least until 10 or 11 am before eating your first meal. The thing with eating immediately after waking up with cortisol is also that you're going to shut down that cortisol response to a certain extent by eating, and that may just cause more lethargy and tiredness for the rest of the day. So you shouldn't be afraid of the spiking cortisol in the morning as long as you don't overdo it and as long as you don't combine it with other cortisol-inducing activities like overtraining and not sleeping enough.