We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
For morning exercisers, a banana before HIIT will not be much help because it takes a while for fruit sugars and carbs to be digested and available. Hours. The banana will just sit in your stomach. Sugar, on the other hand, is quickly available.
When I was younger, even in my 50's, I could eat a huge meal and then in an hour or two run a 10k or half marathon. My meal didn't just "sit in my stomach". Now that I'm much older and less active, yes, if I eat a large meal I stay full for hours even skip the next meal. My guess is that a daily regimen of vigorous exercise speeds up your metabolism and along with that your digestion system. I'm not talking about yoga or other mild forms of exercise but rather vigorous exercise. It would seem to me that this (working hard and eating large meals) is what our bodies were designed to do and our current lifestyle with cars and machines to save us from hard work is contrary to that design.
Yes, and that makes sense. I believe it is true that exercise will slow or probably more accurately interfere with digestion. However I can tell you with absolute certainty that when I was in my 20's I could eat a breakfast that neither of us could eat today given the entire day and then go out and run a 10K or work at manual labor and be 100% hungry at lunchtime. My meal got digested and so far down my GI that I was famished. Now you can tell me it didn't happen but it did. Today, at age 76, if I eat a large meal, breakfast for instance, I dare not work or bend over much even and when lunch time rolls around I will be happy to pass up the meal. So here is my thought: For those who have never expended 1800 calories in 3-4 hours exercise slows your digestion. But for those of us who have done it I can assure you that the food gets digested and moves along and the good stuff gets absorbed and put to use. I know this for certain. So I don't know where the disconnect is, that is why a working man can digest his food in record time even while working hard vs what the doctors know or believe. But I know it to be true. I think the clue to the answer was when I said "For those who have never expended 1800 calories in 3-4 hours". I think it comes down to "we do not know, that which we do not know".
Having said all that, in 48 days my wife and I will once again go on or bi-annual camping trip for a month and we will hike 8-10-12 miles a day. Not much by my 20 something standard and certainly not 1800 calories. I will eat enough for any growing teen boy and I will lose about 8-10 lbs. I will eat a huge breakfast and then climb from 6000' to 8500' over a 8 mile trail and when I get to the top (about four hours) I will be hungry and my stomach will be empty. I know this to be true, we do it twice a year for a month. I literally eat twice as much as I do when I'm sitting at home and work twice as much too.