Intermittent Fasting is very popular right now. Most people do this in hopes of losing weight, improving body composition, and/or getting healthier. I hope the research I found on this diet can give you an educated opinion on whether or not this is actually something you’re willing/wanting to do. One of the many aspects of Intermittent Fasting that I learned from my research is that there are different types. Before we dive into the various types, let’s discuss what this fad diet is exactly. Intermittent fasting is considered to be a period of food abstinence alternated with a period of eating. It could include alternate day fasting or fasting once or twice per week.
The first type is called “Full Day Fasting.” This type recommends 2 days of fasting each week. You fast for 23+ hours, so if you eat dinner on Monday night you won’t eat again until dinner on Tuesday night. Many research studies found that on the days where subjects eat, they eat as much as they want which typically results in a caloric surplus. If your goal with fasting is to lose weight, then this doesn’t seem to do the trick if you’re eating far more than you’re supposed to during the time frame when you do eat.
Another type is “Partial Day Fasting” with an evening eating window. This is also known as the “Fast 5.” During this one, people consume their required calories for the day in a 5 hour time frame and fast the other 19 hours. This one is similar to the “Warrior Diet”, but differs in that the Warrior Diet consists of under eating or fasting for 20 hours of the day, then overeating for 4 hours in the evening.
The final type of Intermittent Fasting is the “Partial Day Fast” with an eating window that’s based around training, if possible. With this one, you eat around the time that you workout or exercise. So, if you do a workout at 9 am, then you eat during the morning. If you don’t workout until 5:30 pm, then you eat during the late afternoon/evening.
Let’s break down the fasting process. Once your body uses up it’s immediate fuel sources, it turns to stored fuel for energy. Since the body has a limited ability to store carbs, it increasingly draws energy from protein. When you don’t have any carbohydrates coming into your body, insulin secretion is depressed.
The creator of Precision Nutrition (which is the most prestigious nutrition program), gave some great insight on Intermittent Fasting. One of the facts he mentioned is that if you’re going to keep your typical North American diet and refuse to make healthier food choices, then calorie restriction might be for you. However, the problem with this is that you most likely won’t be getting good, quality nutrients. By just eating well, supplementing intelligently, and committing to a life-long exercise program, you won’t have to suffer the restriction, deprivation, and scrawniness associated with the Intermittent Fasting approach. Eating well, supplementing, and exercising also proves more powerful than calorie restriction.
Much of the weight loss noticed with a short-term fast is from glycogen, water, and doesn’t seem to substantially impact fat mass. If you’re fasting for spiritual reasons, then that’s great and a completely different story. But if you’re looking to improve body composition and health then don’t jump on board just yet.