Fasting for a week:
- Causes significant changes in protein levels across various organs.
- May have health benefits beyond weight loss, but only after 3 days.
- Switches energy source from glucose to fat after 2-3 days.
- Average weight loss of 5.7 kg (fat and muscle), with most fat loss sustained after 3 days of eating.
Implications:
- Provides insights into the molecular basis of fasting's health effects.
- Paves the way for developing alternative treatments based on fasting benefits.
- Confirms historical use of fasting for specific health conditions.
You will drop a bunch of water at the start if you are eating carbs beforehand because of the water holding the glycogen in your muscles. As you use the glycogen the water holding it also goes, so it isn't fat loss, just water weight.
Yes, correct, so a smaller portion is fat loss but not the full 5.7kg average. I should have been clearer, they did lose a meaningful amount of weight and it does seem to be beneficial, but it is not 5.7kg of fat loss per person on average, it is a loss of 5.7kg average mass with a portion of that being actual body fat.
Right, that makes sense.
Wait you mean no water? Don't you die of dehydration? That doesn't sound good.
No no, they are saying that you’ll lose a bunch of water weight. As far as I know you generally regain that quite easily once you start eating again.
Personally I subscribe to the idea of calories in < calories out. Sustainable weight loss requires good habits and a healthy relationship with food.
There's a lot of data that shows that restricting calories causes your metabolism to lower. Fasting basically causes your body to shift to using fat stores, so it still does have adequate fuel # and your metabolism doesn't fall the same way. It also changes your insulin response, and insulin resistance is one of the reasons you put on weight to begin with. If you're interested, Dr. Jason Fung has written a couple good books on.the subject. He's also put out a bunch of YouTube videos on it.
I've beef doing intermittent fasting for a while, and you do drop a good amount of weight very quickly. Most of it does stay off, but the idea is that you continue to fast periodically for weight management, typically limiting food intake to only a few hours daily.
Causes your metabolism to lower while you’re restricting calories, or potentially for good?
I ask because I ended up doing this pretty drastically for a time (long story, not proud of it) but once I started eating “normally” again, could my metabolism speed up again?
I'm certainly not an expert, but my understanding is that the effect from restricting calories can last longer than the restriction. But it can increase again, and there are many other factors that affect the metabolism. Just like slowing if you don't have many calories it can increase if you have more.
Thanks!
My understanding is that severe shifts in calorie intake vs output can lead to lasting metabolic changes. I think the main example people point to is that all "biggest loser" contestants failed to keep their weight down even when they maintained their diets and exercise for a long period.
It's not really metabolic per se, but hormonal. Hunger is hormone driven. If you restrict calories, you recalibrate your hormonal response to fullness and hunger.
No, these studies indicated metabolic changes: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4989512/
Water weight. You still drink water when fasting.