The Health Benefits of Intermittent Fasting


For those of you who’ve not heard about the concept of fasting for health benefits, the idea of starving yourself for a prolonged period might not be your idea of fun!

It is widely recommended that we should eat lots of small meals throughout the day for optimal health, so what benefits could possibly come from fasting?

Well first of all, we humans are genetically engineered to survive prolonged periods without eating. During the ‘hunter gatherer’ period it was a case of ‘feast’ or ‘famine’ with regard to eating. Our clever little bodies stored essential fat and nutrients during the good times (such as, after feasting on a juicy wooly mammoth), and draw upon these stores when food was scarce.

What Is Intermittent Fasting?

So fasting isn’t a new concept to us, we’ve been un-intentionally fasting for centuries.

Intermittent fasting is a dedicated period of time, (usually 24 hours, once or twice a week) where you only drink water and non-calorific drinks. No food whatsoever.

My reaction when I first heard about this, and yours might be too, was; ‘what’s the point?’ Sure we can survive extended periods without food, but why should we if food isn’t scarce anymore?

Intermittent Fasting and Weight Loss

One of the major benefits to IF, is the effect it has on the way our body allocates fat and how are metabolism is designed.

Our metabolism works on a long term outlook. Forget about what you ate for dinner last night – think about what you ate and what calories you consumed over the last 30 days.

It is this long-term view which affects your metabolism and how fast you burn fat for fuel or store it for energy.

Losing weight is more of a marathon than a sprint, and you need to look at long-term eating habits rather than a quick fix.

So How Does Fasting Work for Weight Loss?

The concept of losing weight and IF is simple and makes perfect sense. For any activity we perform that requires some degree of energy, the body uses an immediate supply of fuel that usually sits in our stomach. If there is no food there to use, the body will draw upon the fat we store in our cells. This fat is used for energy/fuel and we naturally become leaner. Simples!

Another result of not eating for 24 hours, once or twice a week, is you will burn more calories than you consume. Remember we are talking a long-term process. You don’t need to worry about maintaining a calorie deficit every single day, but rather an average deficit over time.

Fact: More calories burned than consumed = calorie deficit & weight loss!

According to Brad Pilon from Eat Stop Eat, the biological process of fasting for weight loss is very similar to that of exercising.

Here’s a short video of Brad explaining the concept:

Other Health Benefits to Intermittent Fasting

Although there still needs to be more research and independent studies, IF might benefit us in a number of other ways.

A study published in the American Society for Clinical Nutrition in 2007 provides an excellent breakdown of specific benefits, including reducing cardiovascular disease, lowering blood pressure, reduction in oxidative damage (meaning greater longevity and less prone to chronic diseases such as cancer), improvement in insulin sensitivity and glucose uptake, as well as decreases in fat mass (weight loss).

More studies need to be conducted with greater control measures, to accurately pinpoint biological changes as a result of IF. However there seems to be gaining momentum for its effectiveness in online forums and blogs, so I expect more positive findings in the near future.

How to Start Intermittent Fasting

Going without food for 24 hours sounds horrific! But in reality it’s not nearly as bad. But if you don’t try it, you’ll never know!

If you are really concerned about how you’re going to feel, start by skipping breakfast only. If you can get through that, try skipping breakfast and lunch – until you can go a whole 24 hours without food.

The easiest way to fast for 24 hours is to have a meal in the evening and then don’t eat again until the following evening. That way you are only missing breakfast and lunch.

Obviously anyone with specific medical conditions such as diabetics and pregnant women should not try IF without consulting a medical professional.

The 5:2 Method (Fasting – But Not!)

If you are still unsure about the benefits or possible risks to intermittent fasting, you could try the 5:2 diet. This means you eat normally for 5 days a week and then a greatly restricted intake of just 500 calories for women and 600 calories for men, for the remaining 2 days.

A recent ‘live study’ conducted by Michael Mosley, for the BBC’s Horizon documentary entitled ‘Eat Fast, Live Longer‘, did just that. His results were impressive.

Mosley states: “I stuck to this diet for 5 weeks, during which time I lost nearly a stone and my blood markers, like IGF-1, glucose and cholesterol, improved. If I can sustain that, it will greatly reduce my risk of contracting age-related diseases like cancer and diabetes.”

He believes the reason for these health benefits occur “when our bodies no longer have access to food, they switch from “growth mode” to “repair mode”.

An article from the LA Times: Mark P. Mattson, chief of the laboratory of neurosciences at the National Institute on Aging, and leading researcher on how calorie restriction effects the brain:

“In normal health subjects, moderate fasting — maybe one day a week or cutting back on calories a couple of days a week – will have health benefits for most anybody.”


Will I lose muscle mass when intermittent fasting and weight training?

This was my biggest concern, and thankfully the answer is ‘No’. Amino acids from protein, needed to build muscle are released slowly into the bloodstream and can take 24 hours or more. In fact it is possible to gain muscle whist IF. (Read Craig Ballantyne’s article: Fasting and Gaining Mass NOT Losing Muscle for a more comprehensive answer).

Will I eat twice as much food after fasting, and end up consuming even more calories?

My experience is that you will want to eat more after a fasting period, but not a significant amount that will shoot your calorie levels through the roof.

Will I become tired through lack of food?

No. Remember your body thinks long-term, not short-term. You will have plenty of fat and nutrient stores to keep you alert.

Will IF cause me to lose weight, even though I don’t want, or need to?

If you are carrying too much weight then the natural result will be a reduction in your body weight. However, once you reach your ideal weight, IF will maintain it.

My Take on Intermittent Fasting

I haven’t yet tried it.. but I will. Although I’m more inclined to go for the 5:2 method at first. I enjoy my food but there are times when I really can’t be bothered to cook. So at least now I can actually forgo eating for quite some time, knowing it will actually benefit me!

Have you tried IF? What were/are your thoughts?


Resources and Further Reading:

Top 10 Fasting Myths Debunked

Is Intermittent Fasting Healthy?

Alternate-day fasting and chronic disease prevention: a review of human and animal trials

Running on Empty: The Pros and Cons of Fasting


Eat Stop Eat

Fasting and Eating for Health: A Medical Doctor’s Program for Conquering Disease

Top Image by Flickr/Nandini Gupta

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