minecraft-resource-pack/assets/minecraft/models/item/bread.json

{
  "parent": "minecraft:item/generated",
  "textures": {
    "layer0": "minecraft:item/bread"
  },
  "overrides": [
    {
      "predicate": { "custom_model_data": 1001 },
      "model": "minecraft:item/broodje_doner"
    },
    {
      "predicate": { "custom_model_data": 1003 },
      "model": "minecraft:item/bedorven_doner"
    }
  ]
}