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Intermittent Fasting Part 2: 2 Fast 2 Furious

Speaking of TOO furious:

Sorry not sorry.

Anyway, hi there! If this is your first time visiting the blog, welcome and thank you for stopping by. I can tell that this is gonna work out between us, because chances are that deep down you know you're a geek like me OR you're just bored out of your mind and need something to help you fall asleep. Either way, I like it.

Today's post is a follow up from last week's intermittent fasting (IF) intro. If you are unfamiliar with IF, click HERE so that you can prep your noggin for today.

I'll wait.

Okay now that you know what IF is, let's talk about some myths surrounding it.

Myth #1: IF will destroy your metabolism. You need to eat 6 small meals a day in order to keep your metabolism rev'd up.

First of all, your metabolism is an amazing and incredible thing. It's like a rubber band that can be pulled and pushed during times, but it always finds a way back to homeostasis (leveling out). For example, when you eat a meal, energy (in the form of calories) is required to digest that meal. We call this the "Thermic Effect of Eating", or TEF. If you don't know what the components of your metabolism are, I know where you can find a pretty graph that someone made that breaks it all down for you. So, if eating produces a thermic effect (burns calories), then eating more, smaller meals throughout the day means I burn more calories than someone who eats 2 big meals per day, right?


Whether participants ate 6 small meals or 2 big meals (same calories, just distributed differently throughout the day) did not result in a difference in calorie burn because everything balanced out. You cannot alter or try to trick your body into doing "X" or "Y". It's hardwired for survival. If you try to burn more fat by doing one thing, it may work initially, but your body will figure out how to increase fat storage by other methods because it wants to ultimately keep you alive. If you're a dieter, there's a reason why the last 10 pounds are the hardest to lose. That's your body balancing things out. So no, just like eating 6 small meals a day won't ignite your metabolism to be the world's hottest most blazing furnace, IF isn't going to take that furnace and plunge it into the Atlantic Ocean like in Titanic where Jack freezes to death. You'll be fine.

Oh, she let go alright.


Myth #2: You will lose fat on an IF diet without having to create a calorie deficit

All diets use the exact same strategy that ultimately leads to fat loss. All diets work because they manage to put you into a calorie deficit. Many do this by having you replace a meal or two a day with a low calorie shake or removing a food group completely. Removing all carbs for example, which essentially removes foods that you may have trouble controlling, is an easy way to remove a lot of calories from your diet. And this works well for fat loss, as long as you're not replacing calories you were eating from carbs with calories from extra protein and fat sources.

Then why so much confusion about an IF diet and fat burning wizardry? I think it circles around 2 facts that we know regarding IF.

1) During the first few hours of a fast, the carbohydrate stores in your liver and muscles start getting used up for energy. Once those carbohydrates are gone, your body turns to the next available fuel source to break down for energy - fat.

2) Fasting also increases your sensitivity to insulin. Increased insulin sensitivity generally results in less fat storage in cells. Now this could potentially be very relevant in aiding in improving insulin sensitivity in pathological situations such as type II diabetes. In fact, a study published in the International Journal of Obesity demonstrated that IF was slightly better than a simple reduced calorie diet for reducing insulin resistance. However, granted that IF research is an underfunded and small field of science, there's still additional validation studies that are needed.

Because of these 2 facts, I can certainly understand how it would be easy to believe that the reason anyone loses pounds of fat on an IF diet is because he/she is burning tons of fat and that the reason the process works is due to "making the body turn on its fat burning mechanisms". Well of course you'll burn fat if you fast long enough. That's the biology of how we were designed to survive in times of food shortages.

Weight loss from an IF diet comes from decreasing calories versus the actual fast. Let me explain.

You're on day 1 of your IF diet. You have determined that in order to lose fat, you need to eat 1500 calories a day. You fast for 16 hours and your body burns 60 grams of fat during the fast.

It's finally time to eat and you consume your 1500 calories during your 8 hour feeding window. Since 1500 calories is less than your body needs in order to maintain its current weight, you lose fat because you're in a deficit, i.e. you burned 60g of fat during the day and you only ate enough to put back in oh let's say 40g for the day. So you're -20g of fat in the bank for the day. That's a deficit, and with time and consistency, that leads to a loss of fat that can be reflected on the scale in pounds.

On the other hand, if you burn 60g of body fat during your 16 hour fast, you'll add it right back during your feeding window if you're eating the same amount of calories that you were before you began using IF as a way to lose fat (meaning you weren’t cutting calories before IF). The take home message here is that there is no valid evidence to suggest that IF will lead to fat loss unless you are expending more calories than you consume at the same time. The IF diet works for fat loss as long as you're simultaneously in a calorie deficit.

Myth #3: You can't work out while you're fasting.

Sure you can. You guys have probably done it, you just don't know it. If you've ever worked out in the morning on an empty stomach, you've totally worked out while you're fasting. Unless you're an athlete who has to have his/her nutrition on point for performance reasons OR you're just a person who feels better working out after breakfast, it's not the end of the world to not eat before an early A.M. workout if you had a good dinner at 7 p.m. the night before.

However, the longer you go without eating, the more it will impact your workout. For example, it's probably not a good idea to run sprints 15 hours into a 16 hour fast (remember, your body loves carbohydrates for workouts, and granted that fasting for a long period of time will deplete carbohydrate stores, your workouts could feel pretty crummy). Pay close attention to how you FEEL, and if you know your workouts could be better if you ate something beforehand, for the love DO IT. No two people are alike, so it's okay to tweak things and make your own rules.

Take home message:

At least for now, MOST evidence shows that when you eat isn't important. There are studies that suggest otherwise, but the problem right now is that there aren't enough of these studies being conducted, and much of the existing evidence suggesting that meal timing for fat loss is relevant are terribly flawed. That doesn't rule it out in my book, it just means we need more carefully designed studies to address IF and all of its potential advantages.

If IF is helping you gain more control over your diet and is something that makes life easier for you (mentally, energy wise, socially), go for it. You're not wrong for it. If you like to eat once an hour, you're not wrong for that either. But it IS important to point out that NEITHER way of life is the "best". There is no "best" diet. If you try IF and hate it, there's nothing wrong with you. If you love IF and it's working well for you, there's nothing wrong with you either. And while we're on it, there is no "best" workout. No "best" method. Having a plan that you can stick to that helps you become more healthy is ultimately what our hope is for everyone. Heaven knows navigating all of this isn't easy, so if you find a plan that makes your quality of life BETTER, good on you.

Jolly. Out.


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