If you're not drinking on a 40 minute "intense" ride it ain't intense. Try harderNothing drinkwise for an hour's riding and nothing to eat unless the ride is getting close to 3hrs or more.
My commute is an intense 10 mile each way trip that takes 40 minutes and never even consider a water bottle for this no matter how hot the weather gets.
A person can only absorb 60-90g of carbs per hour, depending on what those carbs are, so you don't want to eat more than that. The first energy bar I found, SIS, had 26g of carbs in a 40g bar, so theoretically 2-3 of those per hour would keep a rider going if they were riding hard. Most people have different sources of energy though, including sometimes in their drinks bottles, so likely wouldn't eat that many. Little and often is best, so if you only have one energy bar then break it into four and eat a piece every 15 minutes or so.How many energy bars do you take with you? How much food is too much food?