If you’re interested in nutrition, it’s likely that you’ll do some off the cuff research in to different dietary strategies. Intermittent fasting is a food timing protocol where you restrict your eating “window” to a shortened period of the day, so for example, instead of eating from 7am-8pm (13 hours) you may eat from 7am-1pm (6 hours). This article will explain the science, application and reality behind using such a method.
Dietary methods: Think logically
In this industry, you MUST have an open mind. If you don’t you may eventually lead to regret it. Just over two years ago I embarked on writing my first nutritional eBook. The book was titled “debunking dietary myths”. In one chapter I went in to detail about how intermittent fasting was all just a fad and contradicted our own physiology. Luckily, this eBook didn’t see the light of day, as otherwise, I’d look rather stupid endorsing the method now.
The reason I’m telling you this is that it’s important to appreciate that nutrition is a very broad spectrum. There are certain (and very basic) laws that won’t change but apart from that many ways to skin a cat. Intermittent fasting may be excellent for one person but terrible for another. What I don’t want you to do is read this article and then suddenly decide to intermittent fast. If you haven’t been able to consistently stick to a diet and see results for more than 3 months, “specialised” diet methods are not for you.
Intermittent fasting: what is it?
Intermittent fasting is when you fast intermittently. Apologies if you expected a little more of a scientific explanation but let’s not over complicate the matter when we don’t need to. It’s basically restricting the hours in which you eat so that your meals are eaten in a shorter space of time.
Most people will start their day by eating breakfast at 7am, they’ll have lunch at 12 and then an evening meal at 6-7pm. This is a total eating “window” of 12 hours. An example of Intermittent fasting may be to skip breakfast, start eating at 12. and then stop eating at 6pm. This halves your window to 6 hours.
So why should I do this?
A recent study by world leading expert in time restricted eating Dr Valter Longo, showed that calorie restriction and intermittent fasting had significant positive affects on cardiovascular health, insulin sensitivity, mitochondrial health, DNA repair and autophagy. This, in non biochemistry language, means heart health, how well you handle carbs, energy levels and your risk of developing cancer, Alzheimers or dementia.
This puts forward a pretty tangible case for using intermittent fasting. Delving in to the mechanisms behind how it works is beyond the scope of this article. However the theory behind it is quite straight forward as it is based around how we evolved and adapted during the “caveman” era. The human body is designed to go without food for prolonged periods of time.
“No it’s not!!! You’ll go catabolic” I hear all you bodybuilders cry whilst spitting out your oats and whey.
Alright calm down. Of course it would. This is where you need to differentiate the ginormous difference between survival, health and hypertrophy.
Everything we do in the fitness industry IS NOT geared towards survival. Putting on lean muscle tissue is not survival, it is an evolutionary luxury born through the development of modern technology and society. Stressors in pre-historic eras would have meant we lived in extremely demanding environments. Food would have been scarce and so without the ability to go long periods of time with no fuel source, the species wouldn’t have survived. We are built to fast.
But is it the fasting or calorie restriction that causes fat loss?
This is a very good question and although I am no expert, I can confidently tell you that there is a distinct difference between the two. Firstly, let me explain this. Health and weight loss are not the same thing. Health is very much endocrine (hormonally) based. Our circadian rhythm (body clock…kind of) is nice and balanced, we sleep well, eat well, digest well and so on. This is health. Weight loss is thermodynamics. You burn more energy than you consume and you lose total body mass.
Intermittent fasting impacts health. Think of it as pressing the re-set button and allowing your body to clear out the crap and regenerate in a positive way. This is actually what “Autophagy” is. Where IF gets a bad rep is when people endorse it as a way of eating whatever you want. You can do this and it is technically intermittent fasting, but if your body is in a regenerative state, it’d be a better idea to feed it with high quality protein and vegetables than McDonalds. Don’t take liberties with the protocol, the foundations of health will always be the same. Take home point: don’t be a dick.
Will Intermittent Fasting help me lose weight?
No, it won’t. Eating less food will help you lose weight. If you’re overweight, the truth is that you’ve probably got a poor relationship with food and have frequent cravings for decadent treats. If this is the case, putting yourself in a situation where you’re more likely to desire bad foods isn’t wise. Most dietary methods are endorsed through their application on lean and healthy individuals. In a nut shell, everything works better on people with better hormonal balance. People who are highly stressed and have a lot of fat to lose are likely to be less sensitive to Insulin, Leptin and Catecholamines. The balance and efficiency of these chemical messengers is essential for IF to work properly. Intermittent fasting will improve Insulin and Leptin sensitivity but this may be at the expense of stress hormone production. Two going up and one going down isn’t hormonal balance.
What does the science say?
This is the part where I get to sound really clever and say stuff you don’t understand so you think I’m much smarter than I am. Jokes aside, I do think it’s very important to do some homework so I’m not just reciting my own personal experiences and opinions on Intermittent Fasting.
From all the papers and abstracts (I love you all but I’m not paying £30 for one reference) I read, there is a lot of evidence that IF in tandem with CR (calorie restriction) works very well for improving both health and weight loss. Health is generally measured by biological markers such as Insulin Sensitivity, Resting Heart Rate and in some funkier studies, Growth Hormone.
I was only interested in studies that were conducted in humans, showed distinct changes in biomarkers and were post 2013. This is a critical thing about research, you can really find anything to prove your argument, but if was conducted in rats back in 1978 it’s not really going to be “cutting edge” in improving your health.
The general consensus from all the papers was the CR trumped IF for weight loss. This is pleasing as it basically confirms that energy in, energy out will always prevail. Interestingly, it’s safe to say that IF does positivity impact Insulin sensitivity BUT this is where common sense must come in.
Real world application
Now this is what I don’t want you to do. If you read this article and think “I know someone overweight or have an overweight client, Intermittent Fasting would be great for them”. Then you need to calm yourself down and look at the big picture. Science and the real world are two greatly different things. There are variables in the real world that are not accounted for in research and a lot of things that are overlooked (not through negligence but probably through funding more than anything else).
Intermittent fasting is great, but only if your stress management is good, your relationship with food is good and you are looking for a method to enhance your already solid foundations. People who are overweight will enjoy food, taking it away from there for prolonged periods of time isn’t wise. It’s likely to create a higher need to binge.
How to do it
Personally, I prefer morning fasting as it gives me a great mental kick and I can crack on with work. The time is currently 9:24am, I’ve done 2 hours of walking and written +2,000 words. I do find Intermittent Fasting improves my mentality clarity and productivity dramatically. I use it on non training days as it gives my digestive system a rest.
However, if you listen to podcasts and study research by Dr Longo, he states that the opposite is true. Eating in the morning and then fasting at night has much more beneficial affects on overall health. I actually agree with this as we “technically” should only eat when it’s light so we don’t throw off our bodies internal body clock. This being said, I like to enjoy a big evening meal with my family and so am happy to negate these benefits. A 16-18 hour fast from 8pm to 12-2pm is my method of choice. If you wanted to optimise the method, research suggests 16 hours from 2pm to 6am is the way to go. Either way, it still works.
One reason I’m a massive fan of Christian Thibaudeau’s work on Neurotyping is that is explains why certain diet protocols work better for some people and not for others. Intermittent fasting is 100% something that falls in to this category and is definitely not a one size fits all method. If you’re a natural worrier or anxious person, these types of personality traits would be a contraindication to prolonged fasting.
So, it is true, can you burn fat and build muscle at the same time?
I’m going to put my balls well and truly on the line here and say…(drum roll please)…Yes, but you have to earn it.
First let me clear a few things up. It is hormonally IMPOSSIBLE to burn fat and build muscle at the same time, but you can burn fat and build muscle at different parts of the day. So same time means a 24 hour window, not simultaneously.
If you weigh 70kg, are around 12% body fat and can’t deadlift one and half times your body weight for 5 solid reps, you need at least another +3 years of consistently doing the basics before considering strategies such as Intermittent Fasting.
On the other hand, if you’re 110kg, 8% body fat, eat over 4,000 calories everyday, intermittent fasting could be a great way of giving your digestive system a rest, improving Insulin sensitivity and maximising the anabolic effects of carbohydrates. As the research suggest, if you’re in a calories surplus on days you intermittent fast, you’ll still grow due to the excess of energy you’ve consumed.
Are there any supplements that will improve the effects of Intermittent Fasting?
**Part two of this article “fat loss supplements: real or fake” will be live next Sunday. Don’t miss out**
Cerqueira, F.M., Chausse, B., Kowaltowskit, A.J.. (2017) Intermittent fasting effects on the central nervous system: how hunger modulates brain function, Handbook of Famine, Starvation and Nutrient Deprivation, pp 1-18
Collier, R. (2013) Intermittent fasting: he science of going without, National Institutes of Health, Vol. 185 (9), E363-E364
Fehime Beni Aksunger, M. et al (2016) Comparison of intermittent fasting versus caloric restrictions in obese subjects: a two year follow-up, The Journal of Nutrition, Health and Aging, Vol. 21(6), pp 681-685
Harcombe, Z. (2012) Intermittent fasting & calorie restriction: can they help me live longer? lose weight? The Harcombe Diet PRO Plan
Harvie, M.N., Howell, T. (2016) Could intermittent energy restriction and intermittent fasting reduce rates of cancer in obese, overweight and normal-weight subjects? a summary of evidence, Advances in Nutrition, Vol. 7 pp – 690 -705
Mattson, M.P., Longo, V.D., Harvie, M., (2017) Impact of intermittent fasting on health and disease processes, Aging Research Reviews, Vol. 39, pp 46-58
Patterson, R.E., Sears, D.D., (2017) Metabolic effects of intermittent fasting, Annual Review of Nutrition, Vol. 37, pp 371-393