Occasional fasting probably isn’t the end of the world, humans had to endure it pretty regularly so it’s not something we’re totally unprepared for, however being perpetually malnourished can lead to problems.
However, I do think it’s worth mentioning that while there have been some cursory studies suggesting caloric restriction may extend life expectancy I don’t believe any evidence has shown that fasting is required to reap any such benefits (just eating a low amount of calories.)
Further, any claims that fasting is good because it “purifies” or “cleans” or “detoxifies” is woo. The human body is designed to rip everything it can use out of whatever you put in its mouth and get rid of the rest without it tearing you up. Regular food doesn’t cause your body to enter a state where it needs to have a “toxin flush.” If you did have a build up of something toxic it’d probably be the result of something like eating lots of fish every single day that are high in mercury and in that case a single day’s fast here in there isn’t going to get the job done.
Also I’m really sad that I still see people talking about daily weigh ins and gaining after meals as if that is relevant to fat loss at all. One of the worst things that ever happened to people trying to lose weight is they came to the conclusion that well, they need to lose weight.
I’m not looking at anyone in this thread but just speaking generally, about something that is so commonly said so casually but just contributes to gross misunderstanding.
You need to lose fat, and weight is only a very rough measure of fat. If you’re 20 pounds lighter you’ve definitely lost some fat, if you’re 5-6 pounds lighter you may have lost some fat. Or maybe your ate more sodium the previous weigh in than normal and your body is now retaining less water as you went to a normal amount of sodium intake. A large bulk of the food you put in your mouth comes back out, also, so depending on whats in your digestive system that also will impact it.
Even on a pretty good diet losing 2-3 pounds a week many times the amount of fat you’re burning in a single day moves through your body in the form of undigestable matter and water. For these reasons weight just isn’t a good measure by itself of fat loss.
I can’t tell you how many times I get annoyed when I hear someone saying “wow, I can’t believe I gained 9 pounds after that party.” To actually gain 9 pounds of fat you’d have to eat over 30,000 calories. That’s like 15 large pizzas. Now, if you ate a bunch of food at a party and weigh in a lot heavier it just means you may have gained at most a pound of fat and your body is retaining a lot of water because you ate a shit ton of salty food and didn’t properly hydrate, and you still have a good chunk of food inside your digestive tract.
Likewise I think it’s funny how every time someone starts a diet they get excited because they lose 8 pounds in their first week. Again, if it takes something like 15 large pizzas in a single day to gain 9 pounds, how much caloric deficit do you wager you’d need to lose 8 pounds of fat in your first week of dieting? Well, to put it in terms of activity (for my guesstimation of an average overweight person), 8 pounds of fat loss means you’ve created an energy deficit equal to the energy expended by:
45 hours of shoveling snow
31 hours of vigorous use of a rowing machine
28 hours of vigorous swimming
15 hours of running at 10 mph (that’s over 5 marathons worth of running)
You did not lose that much weight.