What Is Intermittent Fasting
A practice that has gained popularity recently is intermittent fasting (IF). Satchin Panda, who is well-known for his research on the topic, prefers to call it time-restricted eating (TRE). That describes exactly what it is: restricting the feeding window to certain hours.
The specific mode is usually called X/(24 – X), with X being the fasting time in hours. So if someone says they do 14/10 IF, that means they fast for 14 hours and eat in a 10-hour window, say only eat between the hours of 10 AM and 8 PM. A 14-hour fast is considered to be the minimum amount of time when IF is effective, with the most recommended split being 16/8. Obviously the longer the fasting window the more beneficial. 14 hours also happens to be the point when it is agreed autophagy takes place in earnest.
The first benefit of IF seems to be that it increases insulin sensitivity. This in turn translates into a better-functioning metabolism. Another benefit is weight loss: given iso-caloric diets, meaning two diets with the same amount of calories, many people report being able to lose weight when adhering to IF, where they had previously hit a plateau. Finally IF tends to increased levels of human growth hormone, or HGH. Studies have shown that increased levels of HGH are associated with higher rates of fat burning and with lean muscle mass gains.
But is it fasting?
A common question is, what constitutes fasting? A general definition could mean no ingestion of any food or drink with a caloric content. This is why most recommendations permit drinking tea or coffee during the fasting window. A minority argues that it can’t be ruled out that the chemical compounds in any drinks other than water – even tea and coffee – interact with our metabolic biochemistry. Hence water is the only drink that should be allowed. We are skeptical of that view as EGCG, one of the main active ingredients in green tea, and coffee have both been shown to be associated with increases in autophagy, a process that is triggered by fasting.
What About Fat?
Many people have questions regarding the interaction of fasting and the consumption of fat. While there is no definitive answer regarding all aspects of that interaction, but there are two things we can be fairly certain of:
- Consuming fat has very little impact on blood sugar levels, and will cause a minimal insulin response. While the exact metabolic pathway that triggers autophagy hasn’t been determined yet, it’s a safe bet to assume that glucose metabolism is involved and even a small insulin release will interfere with it.
- It lowers HGH levels. Consuming fat triggers a release of somatostatin, which is a HGH inhibiting hormone.
There is much more to be said about intermittent fasting. If you are interested in learning more, a good starting point is P.D. Mangan’s website. You can then expand from there based on your interests.