Re:Jason Fung explains why intermittent fasting diets work
by toss1 on Friday October 12, 2018 @01:54PM
(#18203273)
Nope, it doesn't wreck your body, not even close.
This is because of homeostasis. You normally have close to, iirc, 2000Kcal floating in your blood, intracellular fluid, & cells. If you get too much more, then the pancreas will produce insulin to stimulate your body to store the excess as fat.
But when you are temporarily under-fed as with Intermittent Fasting or Time Restricted diet, the insulin simply doesn't arrive to force it out of the bloodstream so it can maintain the levels; levels can also be restored by converting fat stores to maintain the appropriate blood sugar level.
So, you've always got something like that ~2000Kcal store ready to go, and you don't need to worry about 'bonking' on any normal workout with any normal IF or TR diet.
I personally did once manage to do something like you worry about, during off-season training one year in my career in international-level alpine ski racing. I did a 3-day fast, with a solid weight workout (including big muscle groups) on Day#1. No problem. Then, at the end of fasting Day#3, I felt really energetic, so broke the plan and did another really heavy leg weight workout, which went great. However, about an hour+ afterwards, I felt really wobbly/shaky from low blood sugar. This was fixed with a single big orange juice smoothie. It was really cool to feel it take effect -- within minutes. And, there was no break in the training routine after these events, just continued on as usual.
Admittedly it's a single test, but it shows that it can take a lot more than one workout on a TR or IF day to even get to an out-of-the-ordinary state, and it's easily fixed when you do. Not really anything to worry about.
This is because of homeostasis. You normally have close to, iirc, 2000Kcal floating in your blood, intracellular fluid, & cells. If you get too much more, then the pancreas will produce insulin to stimulate your body to store the excess as fat.
But when you are temporarily under-fed as with Intermittent Fasting or Time Restricted diet, the insulin simply doesn't arrive to force it out of the bloodstream so it can maintain the levels; levels can also be restored by converting fat stores to maintain the appropriate blood sugar level.
So, you've always got something like that ~2000Kcal store ready to go, and you don't need to worry about 'bonking' on any normal workout with any normal IF or TR diet.
I personally did once manage to do something like you worry about, during off-season training one year in my career in international-level alpine ski racing. I did a 3-day fast, with a solid weight workout (including big muscle groups) on Day#1. No problem. Then, at the end of fasting Day#3, I felt really energetic, so broke the plan and did another really heavy leg weight workout, which went great. However, about an hour+ afterwards, I felt really wobbly/shaky from low blood sugar. This was fixed with a single big orange juice smoothie. It was really cool to feel it take effect -- within minutes. And, there was no break in the training routine after these events, just continued on as usual.
Admittedly it's a single test, but it shows that it can take a lot more than one workout on a TR or IF day to even get to an out-of-the-ordinary state, and it's easily fixed when you do. Not really anything to worry about.
[Edits - clarity, commas]