CW: Discussions of Food, Diet, weight, body changes, and gender dysphoria
Disclaimer: I'm not a doctor, and this isn't intended to be an explainer on what intermittent fasting is, or how to do it safely, this is just me talking about my experience with it. You can find links to some good beginner explainers on my shaarli instance https://whereis.whirling.top/index.php/?searchterm=&searchtags=IntermittentFasting and it's good practice to talk with a doctor before starting any significant dietary change.
I've been experimenting with Intermittent Fasting for about two months or so at this point (April 2024) so I figured I'd write about it and talk about what I've experienced.
I decided to try intermittent fasting after a youtuber I like went on about it for some time, and explained that one of the theories about it is that essentially, for those who do, living with constant food availability means that we don't practice going into and out of ketosis. This is part of why many of us get hangry and other similar things when our bodies first start feeling like they're running low on carbohydrates to shift into fuel. They're unused to having to pull from fat stores, so they yell about it. I'm paraphrasing immensely, but that's the gist. So, occasionally going without food for long enough to at least begin to engage that system helps your system practice. That's the theory.
Now, I haven't been looking to diet. I know that I use the calories I take in to do cool acrobatic things, and I'm not actively looking to restrict them particularly. I spent some time clearing sugar out of my diet, and I minimize 'highly processed' foods, (I make a bit of an exception for fake meat products, as a vegetarian who's still learning to like beans) and I'm very confident that what I use to fuel my body is good for me. So I'd not really considered fasting to be something with any real benefit to me. But something I have experienced pretty consistently is that I'll "run out of calories" and go into what I describe as "power save mode" when dinner is delayed by much of any time at all. I become relatively non-responsive and I'm extremely lucky that I have a caring family with people in it that like to make food, otherwise I'm not sure what I'd do in that state. I think I used to just space out for a while and then eventually realize I should have food and then find something pre-made to eat, as I wouldn't have the energy to actually make something tasty or healthy. So I dove in and did some more research. At the time I was researching, the general consensus scientifically seemed to be that it works as a diet, just like any other form of calorie restriction. It seems to work better than many forms of calorie restriction in that it doesn't seem to cause a loss in muscle tone/strength, it doesn't trigger 'starvation mode'- i.e. the body storing more calories as fat in response to a perceived lack of available food, and it doesn't seem to have any significant negative effects on most people after going through an initial adjustment period. There are a few health conditions one can have that will make a doctor strongly recommend against trying it, but I do not happen to have any of those, so that was irrelevant for me.
Now, there are many methods of "Intermittent Fasting", I have chosen something frequently called "Modified 5:2". That means that five days during the week I eat like normal. Then two days of the week, non-consecutively, are my fasting days. It's considered 'modified' because I do eat one small meal on those fasting days. I join my family for dinner, which tends to work out for me with essentially making it so that each fasting day is a sequence of one ~ 19 hr fast, followed by a ~ 14 hour one. In my case, as I work out on M-W-F, I have scheduled myself Tuesday and Thursday as my fasting days, so I can make sure I'm fueled appropriately for my work outs and relax about food with my family over the weekend.
I expected this process to be really difficult. I respond so poorly to not having food on time. I had read in multiple places that it takes about a month of adjusting to it before it becomes easy. So naturally I was very surprised when my first fasting day was a breeze. The only thing I craved at all were the snack bars I regularly ate. ..which were also the last consistent source of (admittedly a small amount of) refined sugar in my diet. In light of that realization, I decided that though I wasn't trying to drastically change my food intake, I was going to find a different substitute for those bars. I did, and have finally become the pubescent boy who will eat all the leftovers in the fridge, cold, right out of the tupperware. But the cravings for snack bars on fasting days stopped. Now, despite how easy my first fasting day was, some fasting days are still harder than others. It's easier for me if I'm invested in a task, harder if I'm around a lot of food smells. I tend to spend a lot of time in the kitchen as a habit, and that's shifted somewhat during fasting days.
I have experienced a big reduction in 'power save mode' moments, which is exactly what I was hoping for. I reached a point where I realized I was not eating enough to keep up with my exercise and muscle development, so I increased how much I'm taking in on my 'normal' eating days. It's not drastic, and I'm not pushing myself to do anything other than eat when I'm hungry and stop eating when I feel full. I try to space out my food intake on 'normal' days so that I can really check in with how hungry I am or am not, so I don't find myself binging in response to the restrictions on my fasting days.
So, I'm getting what I was hoping for from it, in other effects:
All in all, it's been a really good practice for me. I'm still honing in on making sure that I'm eating enough, and figuring out how large of a meal on fasting days works best for me. Currently I've been sticking to a rough estimate of "single portion of whatever we're having for dinner, don't get up for seconds", but I may reevaluate that if I'm still losing weight after increasing my intake on non-fasting days.
Update July 2024: In trying to make sure I'm consuming enough to work out safely, I've updated the fasting day single meal to "eat until full". This has been an improvement. I now actually have a scale to keep an eye on my weight, I don't want it getting too low. I'm still feeling very healthy and happy, strong and alert.