I started fasting every Monday for multiple reasons: reduce caloric intake, the recent studies on reduction of cancer growth (family history cancer and heart issues), and optimizing brain functions.
What are some of the downsides to doing this?
What are some of the downsides to doing this?
One potential downside to steady regimented fasting _when combined_ with caloric restriction, is a decrease in your basal metabolic rate (BMR).
Our bodies are very good at adapting to "the new normal" and will optimize itself to function on the fuel you give it. This is true in both directions. If you eat less, your body will learn to live on less, and if you eat more, eventually your body will ramp up to try and burn more energy to try and reach an equilibrium.
When fasting, it's important to keep your caloric intake up during brief eating windows. Otherwise, your body will adjust, and when you stop fasting, the slightly increased caloric intake will cause you to gain weight before your body readjusts to the new normal. Many fasting theorists suggest that fasting at random intervals is the best strategy for weight loss without reducing BMR. If your body is used to burning 3000 calories a day just to keep you alive, it can't ramp down those cells immediately so it needs to instead convert stored fat to energy and burn that instead.
These aren't fasting specific, but oftentimes in the western world, we begin fasting as a means to an end (weight loss) and often combine it with other dietary changes, like eating less/healthier.
The other downside is literal starvation or the development of an eating disorder, but those are pretty obvious.
I saw a low-budget documentary on YouTube[0] a couple of weeks ago talking about "fasting retreats" in Russia and now parts of Europe that are seeing great results with patients water fasting for 2+ weeks. They're treating everything from Diabetes to arthritis and dementia. Pretty cool stuff.
Personally, I definitely have seen the light and will likely continue fasting regularly in some form the rest of my life. Since I just turned 26 last month, that's going to be a while! I'm currently half way through a 72 hour fast and feeling great. Just had a cup of coffee and some electrolyte spiked water this morning. I still have about 50 pounds to lose but I'm hopefully for my future now and I'm a lot healthier.
Check out The Complete Guide to Intermittent Fasting. The research he cites shows that the effect you describe occurs in caloric restriction diets, not fasting. Fasting increases HGH and maintains BMR.
Perhaps what you are describing is the early days of fasting when your body is becoming fat adapted and you feel a bit sluggish, but after a short period your energy levels return to normal (for me it was less than a few weeks, 5 years ago, and my wife just started fasting with me and she is adapted and back to full energy while fasting after two weeks).
Fasting enables us to not have to focus on calorie restrictions to see a reduction in body weight. However, if you only eat 500 calories a day, eventually you will run out of fat and your BMR will go down as you approach a lower BMI.
It's a very slow and gradual process, but it does happen. If you've got plenty of fat to burn, not a huge issue, but as you lose weight it can start to apply more.
Anecdotal evidence also suggests that people who stick with a very strict IF schedule tend to see slower results and bigger plateaus than those who change things up more often.
I agree with your anecdotal evidence. I do 36 hour fasts 2x per week, and otherwise do 20-22 hour fasts. Every now and then I do a longer, 48-72 hour fast. I am in awe of people that get to 5-10 day fasts and hope to work up to this over time, perhaps on a quarterly basis.
Fasting is one of the things that a lot of LCHF practitioners eventually gravitate towards because once your metabolism is used to burning fat, you're not hungry all the time and eating becomes optional. I typically eat two meals a day but sometimes one is more than enough.
I have tried fasting here and there but getting better at it is one of my goals. My main difficulty right now is easy access to food (being stuck working from home most days) and the social pressure of being the only one in the house who has committed to LCHF.
One way I've gotten through this recently is to use a pre-packaged meal delivery service. I order 30 meals at a time for $175 and that lasts me a month or so eating 2 per meal, 4-5 days a week. If I'm hungry, my food options are what's in the freezer, or a bag of popcorn.
I've found one of my biggest motivators for fasting is actually the pride I get from discussing it with friends and family. I'm not a prideful person, but it feels freaking great to boast nonchalantly about not having eaten food in a few days. The results also speak for themself as well.
If you don't have a fasting tracker app, I recommend finding one you like and trying to get some others on board. If you're interested, I have a group from posts on my blog that people hop in and out of [0]. Anyone feel free to join and post updates and I'll keep an extra close eye on it for the next few days.