There are some foods that have a caloric deficit, such as celery or super low like pickles.
It’s not a true fast, but you do not lose all the effects of fasting. I am a big proponent of 25-50 calorie fasted days, and do them a lot. On fasted days I’ll often have pickles and fiber like you said, to the tune of about 25-50 calories. Keeps the gut bacteria eatin and the bowels movin. On longer fasts, every 3 days I’ll take a teaspoon of coconut oil along with the pickles, as saturated fat clears you bile duct and helps prevent against gallstones that can form on long fasts.
The proof is in the broscience: A master signaling pathway for your body’s metabolism is mTOR, and suppression of mTOR is how your body knows its fasting. The longer you fast, the further mTOR deregulates. It takes 10g protien or glucose to up-regulate mTOR by amounts significant enough to end fasting metabolism. So long as you keep it to >5g carb/protien per meal, the outcome will be immeasurable. Sidenote, fat does not effect mTOR signaling. So in theory you could eat like 500 calories of lard a day and still be “metabolically fasting” tho I would not recommend that!
No. You don’t eat when fasting. Only things like bone broth or black tea & water. But I wouldn’t even do bone broth tbh. I’ve just heard people consume that on fasts even though they’re quite strict
Well, I personally like the dirty fasting approach. If the food you eat is keto, you will be in a state that is qualitatively like fasting in most aspects, but of course you will be losing less weight since you are consuming calories.
It is better to eat a slice of cheese, which will put you back 100 kcal, which is around one hour of resting metabolic expenditure, and then continue a fast than to fast a few more hours and break with ice cream or pizza.
Also, some foods, like pickles, sauerkraut and kimchi, are very very low in kcal, but will give you a boost in electrolytes because of the salt and will also help with probiotics.
So, in short, if you understand how fasting works, it is ok to tweak it in a way that serves you best and fits your routine. In this case, keeping it to foods with a very low insulin response will be essentially just as good as fasting (except, of course, for the kcal ingested). If you are aiming for things like autophagy, then things get murky and it is hard to tell.