There's been a lot of discussion about the advantages of intermittent fasting (IF) in the community lately. Paul Jaminet mentions its role in the function of the metabolism as well as it's role in boosting the immune system. In his novel, Health Diet, he discusses how IF may be helpful for those attempting to shed weight, among other benefits.
Intermittent fasting is an eating pattern where you cycle between times of fasting and eating. It does not state anything about which foods to eat, but instead when they should be eaten by you. There are numerous different fasting methods, all of that which split the days and weeks to eating intervals and fasting intervals.
Most people fast; daily, while they sleep. Fasting is often as easy as stretching that. You can drink water, coffee, tea and other non-caloric drinks, although no food is permitted during the fasting period. Some forms of intermittent fasting allow small amounts of low-calorie foods . Taking supplements is generally allowed while fasting, as long as there are no calories in them.
From an evolutionary perspective, intermittent fasting has been likely the ordinary state of affairs. There were no restaurants, no grocery stores or convenience stores, and food was not nearly as readily accessible or easy to come by as it is today. Nor were there watches, lunch breaks, programs or the sort of construction and routine we have in today's world. This means it is very likely that our paleo ancestors had days when they ate lightly or did not eat, and possibly did move 12-16 hours between meals on a regular basis.
Therefore, while intermittent fasting is a part of our legacy, and that it can be useful in certain situations, Its not believed to be a suitable strategy for everyone. Why? Because cortisol levels can be elevated due to fasting. One of cortisol's effects is that it raises blood glucose. In someone with blood glucose regulation difficulties, fasting can make them worse.
This has been seen again and again with many patients. Many patients have blood sugar imbalances. And it is usually not as straightforward as "high blood sugar" or "low blood sugar". They frequently have a combination of both (reactive hypoglycemia), or strange blood sugar patterns which, on the outside, do not make much sense. These folks are not currently eating a Standard American Diet. Most of them are on a paleo-type or low-carb dietplan. Yet they have blood sugar issues.
In these cases, cortisol dysregulation is almost always the culprit. Whenever these patients try fasting, their blood sugar management gets worse. Its been frequently observed that blood sugar readings in the 90s and even low 100s are recorded from fasting, in spite of the fact that they are eating a low-carb, paleo-type diet.
That's why intermittent fasting is often not recommended for those who have blood sugar regulation issues. Instead, its suggested that they eat every 2-3 hours. This helps to maintain stable blood sugar during the day and prevents cortisol and other stress hormones like epinephrine and norepinephrine from becoming involved. When patients that have been fasting and experiencing high blood sugar readings switch to eating this way, their blood sugar numbers almost always hastens.
There's a controversial standpoint about how eating every 2-3 hours is "normal" in the evolutionary view. But neither is driving in traffic or staying up till 2:00am on Facebook. It's not a set of rules, although the paleo template is there to direct us. This should also be a reminder that there's no "one size fits all" approach when it comes to healthcare. Successful therapy depends on addressing them and identifying the underlying mechanisms.