The Beginner’s Guide to Intermittent Fasting – 2017 Update


“…But Tony the Tiger tells us that breakfast is the most important meal of the day! Grrrrrreat!”

This rule has become so commonplace throughout the society as a whole – especially in the health and fitness industry – that it’s readily accepted as fact:

“Want to lose weight? Make sure you start off with a healthy breakfast, so you can get that metabolism firing first thing in the morning!  “Eat breakfast like a king, lunch like a prince, and dinner like a pauper.”

“Want to lose more weight? Make sure you eat six small meals throughout the day so your metabolism stays operating at maximum capacity all day long.”

There are even studies that show those that eat earlier in the day lose more weight than those who ate later in the day or skipped a meal.

So, eat breakfast to lose weight and obtain optimal health.  

Case closed…right?

Maybe Not. Maybe there’s way more to the story. As skeptics, we operate from first principles: what if there’s science and research that shows SKIPPING BREAKFAST (the horror! blasphemy!) for optimum efficiency, maximum muscle retention, and body fat loss?

After firmly being on “Team Breakfast” for 28 years of my life, I’ve skipped breakfast for the past 3.5 years and will most likely never go back!

I want to share with you a concept about skipping breakfast (and other meals), and how your health can benefit as a result.

Tony ain’t gonna be happy, but today we’re talking about intermittent fasting. Even Boy George is getting in on the Intermittent Fasting Action (and has read this article!):

This is a topic that is controversial (which is funny – you’re just skipping a meal) as it turns a LOT of conventional wisdom on its head. This is why this article is filled with more sources and citations than the normal Nerd Fitness article. Here we go. 

What is intermittent fasting?

Seal

Intermittent fasting is not a diet, but rather a dieting pattern.  

In simpler terms: it’s making a conscious decision to skip certain meals on purpose.

By fasting and then feasting on purpose, intermittent fasting generally means that you consume your calories during a specific window of the day, and choose not to eat food for a larger window of time.

There are a few different ways to take advantage of intermittent fasting:

  • Regularly eat during a specific time period only.  For example, only eating from noon-8 PM, essentially skipping breakfast.  Some people only eat in a 6-hour window, or even a 4-hour window. AKA “feasting” and “fasting” parts of your days.   
  • Skip two meals one day, taking a full 24-hours off from eating. For example, eating on a normal schedule (finishing dinner at 8PM) and then not eating again until 8PM the following day. So you would eat your normal 3 meals per day, and then occasionally pick a day to skip breakfast and lunch the next day.

Now, you might be thinking: “okay, so by skipping a meal, I just eat less than normally overall, and thus I will lose weight, right?”  

Well, that’s partly true.  

Yes, by cutting out an entire meal each day, you are on average consuming fewer calories per week – even if your two meals per day are slightly bigger than before (which is crucial for losing weight).  

However, as we already know that not all calories are created equal, the timing of meals can also influence how your body reacts.  

How does intermittent fasting work?

Cog

With intermittent fasting, your body operates differently when “feasting” compared to when “fasting”:

When you eat a meal, your body spends a few hours processing that food, burning what it can from what you just consumed.  Because it has all of this readily-available, easy to burn energy (thanks to the food you ate), your body will choose to use that as energy rather than the fat you have stored.  This is especially true if you just consumed carbohydrates/sugar, as your body prefers to burn sugar as energy before any other source.

During the “fasted state,” your body doesn’t have a recently consumed meal to use as energy, so it is more likely to pull from the fat stored in your body as its the only energy source readily available.

Burning fat = win.

The same goes for working out in a “fasted” state.  Without a ready supply of glucose and glycogen to pull from (which has been depleted over the course of your fasted state, and hasn’t yet been replenished with a pre-workout meal), your body is forced to adapt and pull from the only source of energy available to it: the fat stored in your cells.

Why does this work?  Our bodies react to energy consumption (eating food) with insulin production. In addition to this, the more sensitive your body is to insulin, the more likely you’ll be to use the food you consume efficiently, which can help lead to weight loss and muscle creation.

Along with that, your body is most sensitive to insulin following a period of fasting. 

Your glycogen (a starch stored in your muscles and liver that your body can burn as fuel when necessary) is depleted during sleep (and thus during fasting), and will be depleted even further during training, which can further increase insulin sensitivity.

This means that a meal immediately following your workout will be stored most efficiently: mostly as glycogen for muscle stores, burned as energy immediately to help with the recovery process, with minimal amounts stored as fat.

Compare this to a regular day (no intermittent fasting):  With insulin sensitivity at normal levels, the carbs and foods consumed will see full glycogen stores, enough glucose in the blood stream, and thus be more likely to get stored as fat.

Not only that, but growth hormone is increased during fasted states (both during sleep and after a period of fasting). Combine this  increased growth hormone secretion, the decrease in insulin production (and thus increase in insulin sensitivity), and you’re essentially priming your body for muscle growth and fat loss with intermittent fasting.

The less science-y version: Intermittent fasting can help teach your body to use the food it consumes more efficiently, and your body can learn to burn fat as fuel when you deprive it of new calories constantly.  For many different physiological reasons, fasting can help promote weight loss and muscle building when done properly.  

But why does every health book say “6 small meals?”

small plate

There are a few main reasons why diet books recommend six small meals:

1) When you eat a meal, your body does have to burn extra calories just to process that meal.  So, the theory is that if you eat all day long with small meals, your body is constantly burning extra calories and your metabolism is firing at optimal capacity, right? Well, that’s not true.  Whether you eat 2000 calories spread out throughout the day, or 2000 calories in a small window, your body will burn the same number of calories processing the food.  So, the whole “keep your metabolism firing at optimum capacity by always eating” sounds good in principle, but reality tells a different story.

2) When you eat smaller meals, you might be less likely to overeat during your regular meals.  I can definitely see some truth here, especially for people who struggle with portion control or don’t know how much food they should be eating.

However, once you educate yourself and take control of your eating, some might find that eating six times a day is very prohibitive and requires a lot of effort.  Along with that, because you’re eating six small meals, I’d argue that you probably never feel “full,” and you might be MORE likely to eat extra calories during each snack.

Although grounded in seemingly logical principles, the “six meals a day” doesn’t work for the reason you think it would (#1), and really only works for people who struggle with portion control (#2).

If we want to think back to the caveman days, we’d have been in serious trouble as a species if we had to eat every three hours.  Do you think Joe caveman pulled out his pocket sundial six times a day to consume his equally portioned meals in Tupperware containers?  Hell no!  He ate when he could, endured and dealt with long periods of NOT eating (no refrigeration or food storage) and his body adapted to still function optimally enough to still go out and catch new food.

A recent study (highlighted by the New York Times) has done a great job of challenging the “six-meals-a-day” technique for weight loss.  

Martin from LeanGains points out two important quotes from the study:

“…The premise underlying the present study was that increasing meal frequency would lead to better short-term appetite regulation and increased dietary compliance; furthermore, it was hypothesized that these predicted beneficial effects of increased meal frequency could have resulted from more favorable gut peptide profiles, potentially leading to greater weight loss. Under the conditions described in the present study, all three hypotheses were rejected.”

“…We had postulated that increasing meal frequency would enhance the compliance to the energy restricted diet thus leading to greater weight loss, an effect possibly mediated by increased fullness. The present results do not support this hypothesis.”

Remember, the type of food you eat matters. Meal frequency is not nearly as important as the quantity and quality of food consumed.  This study reached similar conclusions.

Why intermittent fasting?

IF fast plate

Because it can work for you. Although we know that not all calories are created equal, caloric restriction plays a central role in weight loss. When you fast (either for 16 hours per day, or 24 hours every few days), you are also making it easier to restrict your caloric intake over the course of the week. This will give your body a chance to lose weight as you’re simply just eating less calories than you were consuming before. Do this consistently, and it can lead to consistent weight loss and maintenance.

Because it simplifies your day. Rather than having to prepare, pack, eat, and time your meals every 2-3 hours, you simply skip a meal or two and only worry about eating food in your eating window. It’s one less decision you have to make every day.

It requires less time (and potentially money). Rather than having to prepare or purchase three to six meals a day, you only need to prepare two meals.  Instead of stopping what you’re doing six times a day to eat, you simply only have to stop to eat twice.  Rather than having to do the dishes six times, you only have to do them twice. Rather than having to purchase six meals a day, you only need to purchase two.

It promotes stronger insulin sensitivity and increased growth hormone secretion, two keys for weight loss and muscle gain.  This was already explained in the previous section with relevant sources, but intermittent fasting helps you create a double whammy for weight loss.

It can level up your brain, including positively counteracting conditions like Parkinson’s, Alzheimer’s, and dementia. As explained here in this TEDx talk by Mark Mattson, Professor at Johns Hopkins University and Chief of the Laboratory of Neurosciences at the National Institute on Aging fasting is grounded in serious research and more studies are coming out showing the benefits: