Personal Science Week - 231123 Fasting
Fasting
The United States celebrates its annual feast day this week, when most of us will indulge in heavier-than-normal eating.
In this week’s newsletter, we’ll discuss the exact opposite: fasting.
Fasting is more than going without food
In PS Week 230504 we mentioned fasting as one of our favorite non-standard treatments: something to try if you’re trying to experiment your way around an issue where other treatments have failed. Despite how easy it is — you literally just stop eating — I’m surprised how few people ever go more than a few hours without food.
Your body was not designed for a world of 24/7 food availability, and I’m convinced this is a key reason why many people suffer too long with health issues. I’ve heard too many anecdotes from people who unexpectedly found themselves without food – on a trip, during a holiday when stores were closed, or for other reasons – only to find that just that one little break was enough to restart their body into a more healthy state.
A zillion years worth of tradition knows this well. Virtually every religion includes food rules: the Roman Catholic tradition includes a Lenten fast, for example; other Christians (like the Greek Orthodox) fast even more regularly. Islam has Ramadan, Judaism has Yom Kippur. It’s hard to dismiss all of these as mere superstition.
But full-blown fasting is tough, and for that reason I’m interested in the “fasting mimicking diet” popularized by the Italian-born USC longevity scientist Valter Longo and now available in an easy-to-use kit for about $150 from Prolon.
Longo’s research claims to have found a balance that gives most of the benefits of a complete eat-nothing-at-all fast while limiting the hunger pains and other side effects. The diet is carefully selected to minimize hunger while keeping the body in the state that takes maximum advantage of going without food.
Try it on Thanksgiving Weekend
The day after Thanksgiving is the perfect time to start the fast, which is exactly what I did a couple of Thanksgivings ago. Most of us get the day off on Friday anyway, so “five days” really only matters on one work day.
I used the official version which comes with everything you need, including detailed instructions. There’s nothing special or even proprietary about the kit ingredients: Quantified Bob Troia gives instructions for how to do it yourself. Aging Advice even gives recipes. But unless you’re already accustomed to long fasts, I don’t recommend the DIY approach on your first try. Five days without food is doable, but it requires some discipline and a tolerance for discomfort.
Bottom line: It was painful, but I highly recommend it, not just for people trying to lose weight, but even for people who are generally healthy (like me). It’s not easy, at least not for me the first time, but now that I’m used to it I find it helpful to repeat regularly.
Although the diet is promoted as five days, it’s really a bit longer. My last meal was finished at 7pm on Thanksgiving Day and my first non-diet meal was at 6am the following Tuesday, a total of 131 hours, or about 5 1/2 days. After that you’re supposed to give yourself a followup recovery day after that for “refeeding”. If you are in a social situation that requires eating, you’ll need to plan accordingly. This is not the kind of diet where you can “cheat” – you must be prepared to follow the instructions perfectly.
Unlike a “real” fast, where literally the only thing you can imbibe is water, the FMD allows some eating. But don’t get excited: the portions are so measly you’ll hardly notice. A couple of olives, for example. A cup of thin pea soup. While this is supposed to help minimize hunger pains, you definitely won’t feel full.
I track my glucose and ketone levels throughout each of my fasts, and sure enough: my body easily drops into full-on ketosis the first day and stays that way the whole time. On the morning of the sixth day, my ketones clocked in at 1.5 mmol/L and blood glucose at 84 mg/DL, for a total GKI of 3.11. I wasn’t hungry at all, but that first cup of bone broth really tasted good!
It’s hard to describe quantitatively the rush of energy and fitness I feel after each fast. Since I’m not concerned about weight, I didn’t bother noting the few pounds I lost. But the real benefits, I bet, are long term — and difficult to quantify. By subjecting your body to a temporary and reversible shock, your immune system gets a stimulating reminder to remain alert. Whether I can measure that or not, my personal experience is that it’s well worth the few days of trouble.
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Yes, I've also read elsewhere that fasting, even of the intermittent variety, can be very beneficial, particularly for those who are insulin-resistant or who have Type 2 diabetes.
I'm not willing/able to go days without eating but often skip meals. The idea that one needs to eat three regular meals a day is misguided and is not particularly helpful in terms of maintaining good health.
Many of the people I work with "graze" throughout the day. While most are younger than I am, practically all of them are heavier and some of those are likely headed for diet-related health issues as they get older. A number already have some, and a few are no longer alive due to the extremely poor quality of their diets.