This is getting a little deeper than this simpleton mom can understand. LOL No, my kids aren't going to be professional athletes. They just want to do well in the activities they have now (and they are at a slightly higher level than average at this point with some expectations placed on them from coaches and teams) and nutrition can impact that. We have obstacles such as an ultra picky, sensitive to texture in foods kid, school hours that make after school competitions harder to hydrate for and eat properly for (you have to have a note to have a water bottle at school from a doctor. My kids have the note but they go from class to class carrying their chrome book, school books and materials and aren't allowed to use any type of bag for this per school rules, major pain--- one son will still drag his water bottle with him and the other won't often). I'll take this all into consideration. Still like a good old fashioned banana before working out myself. :>)
Hi, is there a reason they can't sip some fast carbs in small amounts throughout? Nausea would most likely be caused by large amounts of food and by fats.
Sucrose might be best for energy replenishment between high intensity events with rest periods (like CrossFit), because it's more insulinogenic than glucose/starch. If sucrose is a problem, or if there are no rest periods, there's maltodextrin or dextrose. If taking in too much water is a problem (bathroom breaks) then there are glucose tablets like diabetics use.
In the small window, they can drink some slower-burning uncooked oatmeal with water in a shaker which would give more caloric density and be more filling. There was also a very trendy slow burning starch from corn (I forget the name) a few years ago, which led to VERY high priced drinks that are marketed to pro athletes and the like, and also for medical uses. But corn starch or even canned creamed corn would be similar.
Boy, what a pickle! In my day lunch was at noon. We ate as quickly as possible, then hit the school play area and played sports until class started again. In those days, the organizes sports activities were after school and I can't remember being hungry or having a hard time of it -- the young can do anything! I guess the question depends on how old your kids are and how intense their participation is -- whether they are serious athletes or just like to play. I grew up in Southern California where the weather was good all year round, and we played all year round, and I can't ever remember anyone needing to eat in order to do it. I also don't remember being hungry because I was too anxious to get to playing. I do know we ate a big breakfast, there was a snack period, and lunch wasn't that much food. But times have changed so much, there is so much more organized play now than an old guy like me had unless you were a really good athlete and made the school team, which wasn't until high school. In junior high, again, we played after school but I still can't remember anyone caring about food at that age and we just waited until dinner. But soccer and running are both aerobic sports, and if you eat too much right before you will risk a stomach ache. With resistance training, heck, you can eat while you're doing it. Also, both of those activities need carbs, not protein so much, as they require the expenditure of a lot of energy but don't require a lot of muscle building. I guess I'm coming down on the side of hydration and electrolytes being more important in those activities than food provided they ate well at breakfast and lunch. So how serious of athletes are they? Do they have coaches who played seriously and therefore would have been coached up by nutritionists (all serious athletes have nutritionists nowadays)? I know what older athletes would do -- take supplements and drugs that speed them up. Not so good for kids.