My daughter & brother both can tolerate berries if they're in the form of a well-blended smoothie, not whole form. Blueberries/strawberries are the least seedy, but they do fine with raspberries too. Blackberries cause some trouble and take a LOT of blending.
We use yogurt or kefir sometimes to make it milky, or dark cherry juice (full of antioxidants & natural anti-inflammatory) to stay on the fruity side.
Use honey for sweetener, maybe throw in coconut flakes &/or flax seed for fiber.
Add bananas, orange juice, oranges/clementines, apple juice, whatever other fruits you're feeling for.
Make one whenever you get the sugar craving. Also a great way to keep your vitamins in check.
ALSO, we keep frozen berries in the freezer & use them as ice cubes to sweeten our water. Better than juice with no sugar, and you can eat the berries at the end for a little fiber & antioxidants.
Your tastebuds will stop craving crummy refined sugar very quickly, and you'll stay full longer from high-fiber berries as well.