Intermittent fasting: fact or fad?>

Posted Fri 1st Feb 2013 8:27 PM by Dan Britchford in Nutrition

If you’re a keen exerciser and/or dieter, or you spend a lot of time around people who are, chances are you’ll have heard about the craze that is intermittent fasting. If you haven’t, don’t worry, you may just be about to be introduced to the best thing they never taught you at school…
(this one runs a little long… but it’s worth it)

So what is it?

Intermittent fasting is the process of suspending eating for long periods, in between periods (or ‘windows’) where you do all your eating.

So basically, you don’t eat for say, 16 hours, and then you eat all your food for the day in an 8 hour time-frame. Sounds ridiculous doesn’t it? why would you ever do that? It flies in the face of conventional meal times, and everything you’ve been taught about nutrition (especially if you have ever subscribed to the 5-6 small meals a day malarkey in the past).

Well, bare with me, because as odd as it seems – there is a lot of science behind this particular ‘fad’ diet, suggesting that it improves any number of things from general health and losing fat, to building muscle.

The research, the benefits, and why you should do it

Fasting has been a topic of research for a long time in the scientific community, and some of the results when you look at them, are truly staggering.

Here’s a short (and by no means complete) list of what fasting has been shown to do in research studies:

  • Extend predicted life in animals
  • Have positive effects on many markers of health
  • Decrease insulin levels
  • Increase insulin sensitivity
  • Decrease blood glucose levels
  • No reduction in metabolic rate
  • No reduction in exercise performance
  • Increase fat burning
  • Increase growth hormone levels
  • No reduction in muscle mass*

*for this last one to be true, you have to be involved in some kind of weight-training.. usually three times a week is a good target

That, is an amazing list.

Why things like increased insulin sensitivity, growth hormone, and decreased blood glucose are good things for your body.. is worth another article in themselves – and I’ll get to that – but the take away things here are that fasting can increase your life expectancy, help you lose weight, and even gain muscle.

The gain muscle one may not be obvious to most, and I’m cheating slightly, because the increased growth hormone levels are actually what backs up the claim that fasting can help you gain more muscle than a standard diet – and I haven’t explained why that is. But for now, just take my word that having more growth hormone is a very good idea for helping the body build more muscle (some people actually inject it to aid in this*…).

*don’t do that

A lot of what you hear on the internet is that fasting will steal all of your muscle mass, and leave you unable to perform well when you exercise – and it’s simply not true.

In one of the experiments researching fasting, soldiers exercising to exhaustion after not eating for three and a half days were compared to those exercising to exhaustion after just eating a meal. The difference in physical performance? none.

Several studies have had both men and women fasting over long periods of time, and every time a weight-training regime of 3 times a week or more has been introduced, the result has been the same – no loss in muscle mass.

In one particular study the participants only consumed 800 calories (thats about 250g dry-weight of pasta) a day for 12 weeks, with only 80g of that being protein – and they all maintained muscle mass whilst losing fat.

There is a long list of studies that back up these claims, and I only want this article to be a summary. So if you don’t believe me (and why should you?), I will be adding another article which will cover the science and research behind intermittent fasting in the near future, so look out for that – or do your own research.

Why shouldn’t I follow other diets?

Nearly every diet is going to work for you in the short-term. As much as the proprietors of such diets may rave about how certain aspects and nutritional ideas are making the real difference in your weight loss while on their diet, it’s always the overall reduction in calories those diets encourage that is causing your weight loss.

Research has shown that the only proven method of weight-loss is caloric restriction

What that basically means, is the only way to lose weight is to take in less calories than your body needs, or to put it in nutritional terms – maintain a caloric deficit.

In any scenario, thats true. Even if you live off a diet of pure sugar, your body has a standard amount of calories it has to burn to function every day (your basal metabolic rate) – and if you aren’t taking in enough calories to meet those energy requirements – you are going to burn some body-fat and lose weight.

Most diets will usually promote low calorie foods, when you think of dieting you think of salads and leaves and all things green, right? All very low calorie foods. In fact some greens are actually negative-calorie! which means they take more energy to digest than they actually give you once digested. (I bet you want a list of those, don’t you?).

The same things are true of promoting whole-grains and the like in your diet – they are going to be lower calorie than say, cupcakes. So you are cutting your total calorie intake by following these diets, and that is what is enhancing or causing your weight loss.

So most diets will work, at least in the short-term, but;

Evidence has shown that many of these diets promote higher short-term weight loss, but when they are examined in the long-term, this weight-loss evens out.

This is because that calorie deficit you are needing to lose weight (caloric restriction) is down to you adhering to that diet 100% of the time, and diets that promote things like no carbs, or no sugar, or that you eat salads 24/7 are very hard to stick to all the time. You want cupcakes, I want cupcakes.

Back to intermittent fasting

Fasting is actually easier to stick to than conventional ideas of dieting

So whats the difference here? Research backs the idea that fasting is easier to adhere to on a long-term basis than other diet types. The truth is that while it’s hard to measure it scientifically, fasting makes you less hungry. I personally never get hungry, even after fasting for nearly a day.

The ‘hunger’ you normally feel is actually not due to your body needing energy at that exact moment, it’s down to a hormone called ghrelin, which basically rears its ugly head at times you are accustomed to eating – and causes you to feel hungry. Fasting will blunt your hunger, and you’ll find it a lot easier to stay away from calorific treats, and to maintain that required caloric deficit. This I can’t prove to you through numbers and figures, you’ll just have to take the leap.

Ok, so how do I use IF?

First things first, you can’t just go around skipping one meal and thinking ‘yay I have all those benefits’.

The shortest period of fasting I would recommend is 16 hours, thats the minimum mark where I think you are getting the majority of the benefits listed above. You can fast for longer if you like – the benefits actually increase significantly all the way up to the 32hr fast mark and from there at a slower rate – and it doesn’t have to be hard. Think about it.

If you had dinner at say 8pm, then you went to bed, got up for work and then ate again at 1pm – you’ve just fasted for 17 hours. So all you had to do was skip breakfast!

And no, breakfast isn’t the most important meal of the day!

Breakfast actually increases hunger in a lot of individuals – we’ve all been that person starving two hours after eating a bowl of cereal – and it is in no way a necessary meal. Personally, I found as soon as I started skipping breakfast I was less hungry throughout the whole day, and there are a multitude of people who agree with me. There are some scientific ideas why breakfast makes you hungry, horribly complicated ideas, which I may try to get across in another article.

The take home lessons

So, if you want to try intermittent fasting – and I really can’t recommend it enough – all you have to do is skip breakfast everyday. It doesn’t actually matter what time you fast at, but skipping breakfast is easiest I find. If you want to fast for longer than 16 hours – you may have to skip lunch too, but I recommend easing yourself in to it first. It may seem daunting not eating for that long, and fly in the face of the well-rehearsed eating routines social convention dictates, but I promise that most of you will find yourself less hungry, more energized, and more satisfied than you were before.

In short:

  • Eat dinner between 7-10pm
  • Don’t eat again for at least 16 hours (11am-2pm)
  • Eat all your food in as many meals as you want for 8 hours or less
  • Do it all again the next day

The only other thing you must do – is not overeat during your eating windows. If you compensate yourself for the fast by eating more than usual during your eating hours – you aren’t going to get anywhere – if your aim is weight-loss. Think it about it this way though, you get to eat the same amount in a shorter time.. so you shouldn’t feel the need to eat more.

Personally, IF was the missing piece of the puzzle for me and I can’t imagine going back to the norm. I’m never hungry and I get to eat big meals during my eating ‘windows’, and I love big meals. So give it a try.

– Dan

There is actually a lot more to say about intermittent fasting, some of which I will cover in the article I’ve mentioned about the science and research behind it. But if you have any questions – give me an email or leave a comment below.

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About the author

Dan Britchford

Dan is the Editor/Designer/Developer, and Main Author of liftingthebar.com. His knowledge is gained through forum haunting and an active intrigue into all things fitness and nutrition based with a scientific grounding. When he isn't working on passion projects, or in the gym - he's selling himself trying to make it as a freelance web developer.

Dan has posted 30 times since 2013-01-31 15:06:30

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