One doesn't have to look to far in the history and mythology of human beings to find that the quest for immortality seems to be a universal one. It can be easy to laugh at the naivete of Ponce de Leon looking for the fountain of youth (or for some of us it is), but what about when we start hearing about how our food (i.e. something right in front of us, if you have the means) could actually help us live longer. Such was the question raised by a journalist named Michael Mosely in a BBC special. Sadly, the full special is no longer easily available, but alert reader Jane sent in this article which provides a summary of the points he was exploring. Is there anything to calorie restriction and helping us live longer?
Looks like we are out of luck again folks. The "evidence that was mounting" in Rhesus Monkeys turned out to not be mounting so much. Michael over at Skeptical Raptor has already covered how, even with the use of a primate proxy, there was no evidence that the restriction helped the primate proxies live long. (Also, Michael's blog has a cute picture of a monkey with a bib, and Primate Proxy is my next band name).
But what about other markers that people look at for health? This quote from the author indicates he was able to improve some other parts of his life as well: " I stuck to this diet for 5 weeks, during which time I lost nearly a stone and my blood markers, like IGF-1, glucose and cholesterol, improved. If I can sustain that, it will greatly reduce my risk of contracting age-related diseases like cancer and diabetes."
In short, he reduced his intake (of everything most likely), and his health markers improved. Nothing news worthy here. But the key is that he found a plan that was SUSTAINABLE for him. (Yes, I am shouting in order to make my point). As I have said before, the sustainable, or lack there of is usually what gets people when it comes to losing weight. How many of us have gone on some type of diet, whether it was changing to veganism, going low carb, etc and annoyed the hell out of our friends on social media or in the work place (you know who you are) with your new found religion, um, diet only to be sheepishly sneaking the donuts in later? Why? Because you a) had no long term game plan for how to avoid the donuts (or whatever), b) were doing something completely un-necessary (like avoiding gluten when you don't have celiac disease or some other type of bowel condition), c) were neglecting some important nutrient, like fat, and threw your satiety regulation out of whack, or d) some combination of all the above. Looks like in this experiment on himself Mr. Mosely, a) knew his limits and came up with a long term plan, b) didn't completely cut everything out forever, c) kept all the macronutrients, just ate less of them, and d) well, some combination of the above.
He was also right to point out that no, we don't have good human studies for this, and that you better let your doc know what you are doing if you decide to try this. Permit me to get a little anecdotal on you for a moment; I have more patients than I care to count right now who are on high doses of insulin because they are 1) obese and have a family history of insulin resistance, and 2) their diets contain way more carbohydrate than they should eat for good glucose control. Sometimes they decided "Gee, maybe my CDE is right in that I should stop eating 4 slices of bread at each meal, and I should do better." So on their own, without telling anybody, they cut their carbohydrate way down--without telling me or their provider about it. Soon their blood glucose levels are dropping into a dangerously low range (below 70 mg/dL) and they start having to take tons of glucose tablets to regain normal blood glucose levels, and some of them just give up. Had they let me or their provider know, we could have come up with a schedule of insulin decreases to support them in their new endeavor. (Some people are ok to do this on their own, and they do tell me about it, but at least we are communicating!)
The other part of this that makes me uncomfortable is the association between fasting and religion, and I will be the first to admit that this discomfort is not fully rational. I grew up Mennonite and we did not engage in most of the "High Church" rituals that involve fasting. Fasting was usually reserved for what I could best decribe as times of crisis; for example, when Gulf War I imminent we were to engage in a day of prayer and fasting to appeal to God to stop this (no, it doesn't make sense). Fasting was also employed as a way of purifying yourself in some way (young men who had "lustful" thoughts were encouraged to fast periodically in some churches), and reminding you that there was Something outside of you sustaining you. Quite frankly, as an atheist, when I hear about fasting, particularly when people talk about "cleansing" themselves, not only do I get twitchy because of the bad science, I get upset because are looking at their bodies as something impure. (Hopefully the rest of you are "over" all of this).
Take home message--Intermittent fasting most likely won't help you live longer. Intermittent fasting might help you achieve a sustainable plan for losing weight--but ask your doctor first, particularly if you have existing medical problems.