Interesting because I've been experimenting lately with reducing the fructose in my diet - based on the premise that it's preferentially stored and utilized by the liver (as opposed to muscle tissue) and easily converted to fat......and the jury is still out. Not sure if the trade off (losing out on the fibre, vitamins, taste, etc.,) will be worth it.
In any case, the tuna/apple combo is no post-workout meal to sneeze at. See how it goes and my only advice would be: if you feel tired during your workout, switch to a carb source more conducive to the production of muscle glycogen (e.g., oats, yams, etc.,).