You are in Member Communities . It has a lot to do with texture. Make sure it is smooth. If possible try to add a little distilled water to make the texture really smooth.
Desserts have a lot of additives like cornstarch and sugars as do other foods.
Try him on home made apple sauce at the tip of each spoonful of meat, veggies and he may take it and get use to it. Again, the texture is the key- a good blender to really puree it. All rights reserved.