Intermittent fasting has become a thing. Have you tried it or plan to? Or maybe you’ll be fasting for a few days this Lenten season? For whatever reason you fast, the process will teach you about yourself and provide benefits both physiologically and psychologically.
Whether you’re fasting/feasting a regular number of hours/daily (16/8 seems to be common) or doing an occasional long fast (36 hours is pretty convenient to try, eating dinner then fasting the entire next day then eating breakfast the following day), there are a few insights I want to share.
First of all, take a look at Dr. Jason Fung’s website. He has good information, including the science that will help you understand why fasting is so beneficial for those wanting to enhance their metabolism or lose weight.
I’ve tried fasting of many durations. 40 hours is about the limit for me. In fact, unless you’re really looking to lose a lot of weight, you may not want to go beyond this; at 40+ hours cortisol and adrenaline ramp up and that can increase stress to levels that reduce the value.
If this is all new, start with 12/12. Get through several weeks of not eating for 12 hours and eating a day’s food all within the other 12 hours, usually fasting overnight is easiest. Once that’s regular, move to 14/10 or 16/8. When I was a kid back before the dietary food guidelines were developed, 12-hour overnight fasts were normal, because we didn’t snack like we’re encouraged today. It’s terribly difficult to go more than 3-4 hours fasted for many of us because we have learned to be grazers, regularly consuming quick-burning carbohydrate foods. Off the carbs, off the couch.
Fasting Can Be Scary
If you find you’re having trouble going long periods without food, spend some time reflecting on whether it’s a physiological or psychological need pushing you. I remember my first tries at fasting years ago. I felt fear. I was actually feeling afraid as the day went on. I was apprehensive and couldn’t really tie it to rational thoughts. Reflection and meditation helped.
The fear can be the result of a natural sense of need. More likely, it’s because of a relationship with food that gives food too much emotional power. I also remember feeling afraid of myself. I didn’t trust that I could achieve this goal I set out for myself, that I would fail.
Well, I did fail a number of times until I made it. Each failure taught me something about my thoughts and about my body. The one real surprise? I actually gained more energy the longer the fast went on. Most of us assume we’ll get weak and tired, but it is the opposite. The reason: your body increases hormone levels as you fast, presumably to allow you the energy to go get your food! Fasted at 20 hours is often a critical moment for me — often feeling hungry then — but I get through that hour and suddenly I have all kinds of energy…and no hunger for the next 20.
There have been other times when I truly felt weak and shakey. At times I ended my fast. Other times, I held on through it and the unsteadiness went away. Sucking on coarse salt and drinking extra liquids have always helped. In fact, those are secrets I didn’t know when I started. About 20% of your hydration comes from food, so without it, you need to add more. And salt is often the nutrient that is driving hunger, so eating plain salt when fasting reduces cravings.
The one thing I have never felt is that gnawing stomach pain I once associated with hunger. Not since I changed to Paleo/keto have I felt actual “hunger pangs.” I associate that kind of pain with carbohydrate-dominate diets.
What that means is my body is used to converting fat for fuel, so when I don’t eat fat, my body primarily uses my stored fat. On the other hand, if you’re eating high carb/low fat, your body will be searching primarily for carbs to use and push you to provide them, because that’s what your body is used to. In the short term, this means hunger pangs. In the long term, you’ll likely experience fatigue and brain fog as your body ramps up enzymes that will convert the fat. If you ever heard of the “keto flu” or “carb flu,” this is what they mean.
Having a metabolism that primarily burns fat makes fasting easier. I can’t truly imagine trying to fast the way I ate a decade ago, but I’ve met a few people who do. So give it a try. Fasting seems to be beneficial whatever your dietary preference.