How long was the ride? If I wasn't on vacation, I would have gone for a 90 minute ride last night. I never drink more than usual or eat anything special before an evening ride on a hot day. I do bring two water bottles with me to drink during the ride, but it's just water. I eat half a sandwich (probably ~350-400 calories, in some cases) about 2 hours before the ride, because it's my usual afternoon snack (I eat 1/2 sandwich for lunch the other 1/2 sandwich for snack).

If I ate dinner an hour before a ride (or any exercise) I'd probably wind up with stomach cramps.