Absolutely nothing. I often make myself an icy Milo when I get home from a long ride. If the kids have not consumed every banana in the house, one goes into the blender with lots of Milo, milk, ice and a dash of honey.
In fact, it might be described as the perfect sports drink.
Common sports drinks such as Gatorade supply those carbs, as well as fluids and electrolytes lost through sweat. However, more recent research suggests that adding protein to the mix may further hasten recovery. Hence the new wave of drinks such as Endurox R4 that include protein as well as higher doses of carbs.
In the study, nine male cyclists rode until their muscles were depleted of energy, then rested four hours and biked again until exhaustion. During the rest period, the cyclists drank low-fat chocolate milk, Gatorade, or Endurox R4. During a second round of exercise, the cyclists who drank the chocolate milk were able to bike about 50% longer than those who drank Endurox, and about as long as those who drank the Gatorade.
Go read the rest at the above link.
This video is well worth watching - just to see how a modern athlete gets enough energy into them to keep moving.