There are many different approaches to Intermittent Fasting (IF), which includes multiple books around application and conflicting research studies. I will start out by stating that Intermittent Fasting is not really a diet, it is more so a pattern of eating. In fact, some refer to it as time restricted feeding. It is a way of scheduling your meals so that you get the most out of them. As such, it is flexible and adjustable based on each person’s unique lifestyle. IF doesn’t change what you eat, it simply changes when you eat.
A couple different applications of fasting are:
· 16/8 method
Lean Gains system designed by Martin Berkhan. Fast for 16 hours, eat for 8 hours. For example, stop eating at 8pm and start eating at noon the next day. This lends well to those who train later in the evening. It also helps with adherence to hit a calorie deficit, or to eat less, due to cutting out an entire window of eating (breakfast).
· 24-hour fast
Performed once a week, on a non-training day. Can be an easy way to create a “weekly deficit” without having to create a daily deficit to push towards fat loss goals. If we cut out a whole day of eating, we can eat more the rest of the week. Again, this helps with adherence as you reduce the caloric reduction required per meal to make progress.
As with many other dietary regimens, the secret of success on IF is that it provides another way to create a caloric deficit. In my opinion it shouldn’t be sought after due to the belief it is more efficient at eliciting fat loss, but rather to encourage adherence. Consistency is the biggest factor in success with any nutritional regimen. In some cases, IF lends itself to increased adherence and consistently maintaining a caloric deficit.
Fasting is a natural process and one that our bodies are equipped to handle. When fasted, we get significant reductions in blood sugar and insulin levels, as well as a drastic increase in human growth hormone.
Some of the potential benefits include:
· Improved mental clarity and concentration
· Weight and body fat loss
· Lowered blood insulin and sugar levels
· Reversal of type 2 diabetes
· Increased energy
· Improved fat burning
· Increased growth hormone
· Lowered blood cholesterol
· Reduced Inflammation
· Potential Prevention of Alzheimer’s disease
· Potential Increased lifespan
The reason it says potential benefits is because most of the research to date on IF has been done using animal models. Animals are not perfect models for predicting the human response. Although the research around IF is strong, it must be taken as potential benefits for humans for this reason.
Furthermore, IF could potentially be used to reduce the risk of chronic disease and increase lifespan. Decreased insulin sensitivity, increased fat mobilization, and decreased blood lipid levels are all factors of chronic disease. Improvements in each of these areas are noted as a possible benefit of IF. Another topic, related to longer periods of fasting 24 – 36 hours and beyond, have promise in the process of autophagy (clearing of damaged cells and creation of new ones) and is linked to increased longevity.
IF and Lean Mass Gain
It is not recommended for some athletes or those seeking to build muscle. To encourage lean mass gain and preservation, you want constant feedings and energy coming into your body. Most importantly you need frequent protein feedings. Studies have shown that MPS (Muscle Protein Synthesis) is one of the biggest pre-cursors of building / maintaining muscle. The two ways to spike this process:
2. Eating Protein
Going 16+ hours without eating limits these spikes and the MPS process. Therefore, IF is not recommended for this purpose. If training fasted, make sure to time training appropriately. Ideally, have protein 2 hours post-workout. This could be difficult based on your eating / fasting window in relation to training schedule flexibility.
Be careful with use of supplements and medications while fasting. If you use a multi-vitamin make sure to take it with food, as it can make you nauseous. Some vitamins are fat-soluble. This means they require fats to transport and be utilized within the body. Fat-soluble vitamins are absorbed along with fats in the diet and can be stored in the body’s fatty tissue. They come from plant and animal foods or dietary supplements. Vitamins A, D, E, and K are fat-soluble. Additionally, many prescribed medications require you to take them with food (read the labels).
Considerations for Females
Make sure your doctor is aware, have professional guidance, or have hormones checked during following of this regimen. IF can potentially lead to amenorrhea (loss of the menstrual cycle) which is very unhealthy. This can also occur from an extremely low carbohydrate regimen.
Personally, I have commonly utilized IF to make adherence to my overall weekly caloric goals more readily achieved. As an example, I have used it for managing calories during the holidays or attending an event where I want more flexibility to indulge. I simply start my fast at 9 pm the night before the event and fast 12 – 16 hours with my first meal being at the event. In addition, I have fasted once a week (typically on a weekend) to give my digestive system a break and to improve at handling hunger symptoms. There may also be some benefit to keeping insulin sensitivity in check by using the once a week fasting strategy (as noted in multiple studies). I have found that by going through the fasting process I am more attuned to eating intuitively and have a higher tolerance for hunger pangs when following a fat loss phase (cutting).
Intermittent Fasting is not the pinnacle of dietary strategies. It is a good tool in the nutritional toolbox for those who are “healthy” and looking to get lean without using a conventional diet. It can also be useful for someone who is trying to learn how to manage a healthy relationship with food (sticking to a routine / schedule). It has not been proven to be any better than other methods of fat loss or weight reduction. And in comparison, to standard dieting practices, overall results achieved by those using fasting are near identical. I am rather interested on the application of IF in relation to longevity and look forward to additional research and studies in this area.