High Performance Energy Sources

I've had several endurance athlete-clients lately looking for an appropriate energy source to use during competition that won't cause bloating and gas. During long events, a large FODMAPS load can be consumed, especially if the product used contains more fructose than glucose. Watching the Olympic games tonight, I was inspired to search for a product to recommend, and I found one: Raspberry PowerBar Gel Blasts energy chews. The web site for the product states that the ratio of glucose to fructose is 2:1--very favorable. Even so, each person has a maximum threshold for fructose absorption, so it's still possible to overdo--too much of a good thing. Do you have a favorite high-energy competition product that doesn't aggravate your IBS?