I've been doing time trials once a week since May and I didn't have any GI issues until the hot weather hit. The last 3 time trials the outdoor temp has been around 28c. The TT area does not have any shade and the heat radiates off the pavement so it's probably a bit hotter there than forecasted. The last 3x I've had issues. First time I'm thinking I bonked. Not a pleasant experience but a cliff bar and H2O and 20 minutes later was feeling not so bad. The last two times half way during the time trial I got nauseated. I tried eating 3 hrs before the TT last time and that didn't sit well either but if I don't eat I'll bonk for sure. I'm thinking I must be doing something wrong. What and when do you eat in warmer/hot temperatures outside prior to TT?.