Not all veggies are created equally some are higher in carbs and sugars than others. And it is the dose that makes the poison. The further down on the list of ingredients then smaller the amount in the food. So if apple is almost the last thing listed then there is very little of it used in making the food. If it's the first, second or third ingredient on the list than that can be a red flag.
Like when as humans we go on a diet, peas because they are high in natural sugars we have to measure them into a certain portion size, but green beans you can stuff yourself on. Even veggies from the same family aren't created equally...Iceberg lettuce is basically like eating air, it is filling but is empty of nutritional value but the flip side is Romain lettuce just as filling but chocked full of vitamins and nutrients. A rabbit will starve to death eating nothing but Iceberg but thrive on Romaine.
Mel and The Fur Gang