Intermittent fasting is exactly as the name suggests it is fasting for intermittent periods of the day. It is very definitely not starvation. Starvation is going for a significant period of time, usually several days without any food at all. While this will definitely result in weight loss there is a significant risk of an individual doing long term harm.
Firstly, it will deny you essential elements which the body needs on a regular basis such as protein and micronutrients in the form of vitamins and minerals. Secondly it will do exactly what calorie-restricted diets do and that is to drop your BMR down to fairly low levels making you tired, cold and miserable. Lastly there’s a risk of losing muscle bulk. So, whilst it is definitely not desirable the good thing is it is not actually necessary for the purposes of weight loss. It is only necessary to fast for a certain period of the day.
To understand the science behind intermittent fasting and how it works effectively for weight loss, it is firstly important to have an understanding of the way that the body utilises the various macronutrients that are in food, and also the hormonal mechanisms that are in place that control what happens to that potential source of energy at a cellular level. It is therefore imperative that you look at the presentations entitled Macronutrients and Micronutrients, the metabolism of the three macronutrients, namely carbohydrate, protein and fat, as well as what causes obesity and the presentation entitled Insulin.
In the Nysteia formula the 24-hours day is divided into an 18-hour fasting window and a 6-hour feeding window. This has been done for a very good reason – an 18 hour fast is eminently achievable for most people and importantly it allows the body to invoke its normal homeostatic mechanism of burning fat as an energy substrate when glucose is in limited supply. The 6-hour feeding window is similarly an adequate period of time for most individuals to get their requisite daily calories-in i.e. 2,500 calories for men and 2,000 calories for women on average without them feeling compelled to do so within a shorter period of time.
Most individuals will stop eating at approximately 8pm and then will fast as a matter of routine while sleeping until the following morning. It is then simply a matter of continuing with the fast for a further 6 – 8 hours and for practical purposes this equates to forgoing the normal breakfast and to delay lunch by an hour or so. During this period, it is inevitable that you will get some sensations of hunger and these can be largely relieved by regular intakes of black coffee, green tea or simply tap water none of which contain any calories.
It takes a relatively short period of time for the body to completely deplete its storage of glycogen in the liver. This can be assisted dramatically by taking 30 minutes of cardiovascular exercise and this is the rational of Point 2 of the Nysteia formula. Ideally this is best done immediately upon rising. Once this has been achieved, the body is then fully into utilising its reserve energy source as its primary energy source namely fatty acids which it derives from stored adipose tissue. This will lead to a kilogram of weight loss per week on average.
The other important aspect of intermittent fasting is its regularity. Because humans are creatures of habit once you are into a routine of the 18-hour fasting window and 6 hour feeding window it becomes much easier to tolerate and achieve. And in fact, after a couple of weeks it becomes so routine that you just treat it as a normal way of life.