People have been engaging in fasts for thousands of years, sometimes for religious reasons and other times to enhance their mental focus, or for other reasons. Fasting parallels the natural lives of many animal species from penguins to grizzly bears. Many animals fatten up during a season of plenty, so that they can survive when food is scarce.
Grizzly bears hibernate during the winter, living off the stored fat they accumulated during the summer and fall. Penguins raise chicks when food is plentiful during the Antarctic summer, with one parent tending the nest for days on end, and fasting, while the other hunts.
Every living thing has only a certain amount of energy. It doesn’t make sense to expend that energy on reproduction and child rearing when food is scarce. If the child starves to death, what have you accomplished? Humans, like other animals, are programmed by internal clocks. When food is plentiful, our bodies switch into a mode where reproduction is an attractive option. Conversely, when it has been days since our last meal, we switch into an energy conserving mode.
The current state of humanity, particularly in the developed nations is very unnatural. People in these countries have plenty of food all the time. In the absence of periodic food deprivation, people’s bodies are constantly in reproductive mode rather than energy conservation mode. This makes humans distinct from much of nature in that we have no seasonally specified breeding season. It’s always breeding season, which is why people have birthdays every month of the year.
Fasting is a way of trying to return our bodies to a more natural state, a state in which sometimes food is available and sometimes it is not. If you are deprived of food, your body changes state. Rather than depending on getting needed energy from food, it starts to burn stored fat, in the same way that a hibernating bear lives off the fat that it built up when food was plentiful. As with the ketogenic diets that I have covered in past articles, the fasting body goes into a state called ketosis.
Fasting is related to the CRAN (Calorie Restriction with Adequate Nutrition) diet in that when you are fasting, you are restricting calories. During the fast, your calorie intake is zero, or close to it. Hibernating bears fast all winter. That would be rather extreme for humans. The object of fasting is to improve your health, not destroy it. Unlike the CRAN diet, an intermittent fasting diet alternates periods of extreme calorie restriction with periods during which you can eat normally. There are several popular intermittent fasting diets that differ in how much time is spent fasting and how much is spent refeeding. Perhaps the easiest of these to follow is the 16/8 intermittent fast.
The 16/8 intermittent fast diet does not say anything about what you should eat, or how much you should eat. It only cares about when you eat. Within any 24-hour day during which you are observing the fast, restrict consumption of all calories to an 8-hour window of your choosing, consuming nothing but zero calorie drinks such as water, black coffee, or tea with no creamer during the remaining sixteen hours. Of course, if you consume healthy foods during your eight-hour dining window, you will gain more benefit than if you eat unhealthy foods. Let your conscience be your guide. The 16/8 intermittent fasting diet sheriff will not be checking on what you eat.
The rationale for this regimen is that during the sixteen hours that you are fasting, your body moves into ketosis. Since you are not eating constantly, your digestive tract gets a rest. You also are less likely to consume as many calories as you would if you were not fasting, because you can only eat so much comfortably during your eight-hour non-fasting window. This can lead to weight loss, unless you compensate by overeating while the widow is open.
A further potential benefit is increased healthy lifespan. During the interval when your digestive tract is not working on food, energy can be expended to maintain your body in better health. That change in the way your body operates will give you some of the advantages that the much more severe and hard to follow CRAN diet provides, but without the sense of privation, or the tendency to backslide.
Set your eight-hour window wherever is most convenient for you. Perhaps 8 am to 4 pm will work for you. Or you might skip breakfast and do all your eating between noon and 8 pm. It doesn’t matter when you do it, just as long as you do it. This is a diet that you can get into the habit of following, and stick to it five, or even seven, days per week. The result might be some weight loss, if that is one of your goals. It might also be more years of good health than are enjoyed by other members of your high school graduating class.
Bio:
Allen G. Taylor is a 30-year veteran of the computer industry and the author of over 30 books, including Develop Microsoft HoloLens Apps Now, Get Fit with Apple Watch, Cruise for Free, SQL For Dummies, 8th Edition, Crystal Reports 2008 For Dummies, Database Development For Dummies, Access Power Programming with VBA, and SQL All-In-One For Dummies, Second Edition. He lectures internationally on astronomy, databases, innovation, and entrepreneurship. He also teaches database development and Crystal Reports through a leading online education provider. For the latest news on Allen’s activities, check out his blog at www.allengtaylor.com or contact him at allen.taylor@ieee.org.