A “Fast” Way to Lose Weight

With Intermittent Fasting

March 23, 2016

Intermittent fasting is “trending” with endorsements from celebrities like Jimmy Kimmel, Benedict Cumberbatch and Hugh Jackman. It is more of a pattern of eating than a diet and it is easier than a “diet”. In addition, not only does it help you lose weight as well or better than a low calorie diet, but it also has been shown to help with many other health issues, such as type 2 diabetes, cancer and heart disease.

However, the main motivation to try intermittent fasting is to lose weight. And the simplest, but certainly not the only, reason that it works is due to eating fewer meals. Unless you compensate by eating much more during the remaining meals, you will consume fewer calories.

A “Fast” History of Intermittent Fasting

Until very recently in human history, sporadic or seasonal access to food was the norm. This fits in nicely with the fact that our livers and muscles store carbohydrates in the form of glycogen for quick access, and we can also sustain ourselves for weeks at a time by drawing from our long term reserves – fat.

Fasting, in one form or another has been around for as long as humans, sometimes as a consequence of having limited access to food and sometimes due to religious or spiritual beliefs. It is easy to see that we evolved to be able to function without food for extended periods of time, and it is not hard to argue that fasting may in fact be more “natural” than eating three meals a day “on a schedule”.

What is Intermittent Fasting?

Intermittent fasting is a term used to describe various diets that cycle between a period of fasting and non-fasting.

The three most common ways to practice intermittent fasting are:

  • The 5:2 method where you fast for two days per week and eat normally during the remaining five days.
  • Alternate-day fasting where you eat normally on one day and restrict yourself to 500 calories on the alternate day.
  • The 16:8 method where you restrict your meals on a daily basis to eight hours per day by skipping either breakfast or dinner.Intermittent Fasting vs Calorie Restriction Diets

For a more detailed explanation of intermittent fasting you can go to INTERMITTENT FASTING: IS IT FOR YOU?

It has been shown that intermittent fasting is easier to follow than calorie restriction diets.(1) This is important since most diets fail because they are not followed over the long term. Fortunately, more people are willing to stick with intermittent fasting and adapt more easily to it than a traditional calorie restriction diet.(2) A 2012 study of 16 obese individuals found a high degree of compliance and significant weight loss with intermittent fasting.(3)

Part of the reason that people tend to stick with intermittent fasting has to do with the fact that most experience significant weight loss, and nothing breeds compliance like success.

A large part of that success can be attributed to the fact that our body produces ghrelin and other metabolic hormones which determine blood sugar levels and do so based on our eating patterns. Therefore, if you regularly skip breakfast or dinner your body will stop telling you that you are hungry at that time. This explains why people can adapt to regular periods of fasting.(4)

What the Science Tells us About Intermittent Fasting

Studies have shown that intermittent fasting enhances hormone function, which helps with weight loss. For example, a 2013 randomized study involving 112 overweight women showed that intermittent fasting substantially improves insulin sensitivity and weight loss.(5) Another study showed that two days of fasting can quintuple human growth hormone levels.(6) These hormones are important for breaking down body fat and facilitating the use of fat for energy. As a result, intermittent fasting increases your metabolic rate by up to 3.6% which helps you burn more calories.(7)

Because intermittent fasting causes an increase in human growth hormone, it plays an important part in the maintenance of lean body mass and the decrease of body fat.(8) Raising human growth hormone levels while improving insulin sensitivity results in healthy weight loss. A 2011 review study concluded that intermittent fasting helps with weight loss, but just as importantly, results in less muscle loss than a standard calorie restriction diet.(9)

A 2012 study of 50 healthy Ramadan observers found significant improvement in body fat percentage. Another important finding was that, even though the participants had regained the weight lost during the Ramadan fast six weeks later, they did not gain any additional weight as often happens with many types of calorie-restrictive diets.(10)


Intermittent fasting works both by boosting your metabolic rate – calories out – and by generally reducing the amount of food you eat – calories in.

Intermittent fasting is a powerful weight loss tool that works better than conventional calorie restriction diets because it is easier to stick with and gives superior results.

(5) http://www.ncbi.nlm.nih.gov/pubmed/23591120
(6) http://www.ncbi.nlm.nih.gov/pubmed/1548337
(8) http://www.ncbi.nlm.nih.gov/pubmed/2355952