Stop feeding her the turtle food all together. They are generally high in fat and have too much of some things and not enough of others. Turtles may be picky, but if you feed them what they are supposed to eat they will eat once they are hungry. Kind of like a child.
Red eared sliders should have no more than 25% of their diet being comercial foods. I suggest the pellets and sticks, put them into the water. They are made specifically for aquatic turtles and don't decompose in water quite as fast. Also, since it's put into the water it will be softer and easier to eat. They should only be fed as a treat, if at all.
For young turtles, most of their diet should be animal matter. Small live feeder fish, small crickets, earth worms, meal worms, can all be tested out to see what he enjoys most. Feeder fish are harder to catch, but it will give your turtle exercise. Don't feed earthworms from your yard because they could potentially have pesticides or bacteria that your turtle isn't immune to. Buy them from a pet/reptile store, not from a fishing bait store.
For plant matter you can use edible aquatic plants, different fruits like melons, berries, apples, and other fruits are fine too, depending on what he likes. For greens only feed dark healthy greens like collard, mustard, or dandelion.
Feed a young turtle everyday. Usually in the morning when you turn on the lights, or in the middle of the day/early evening. It's best to feed them the same time everyday. Feed more animal matter compared to plant matter. As he gets older, you should be feeding more plant matter than animal matter.
If you have any questions feel free to e-mail me. Mayri5289@yahoo.com
Turtle owner for 6 years.
Zookeeper for 5 years.