[observer]

I definitely agree that a senior checkup is in order, and a change in food to something healthier than IAMS.

Is she losing weight, or, as you say it, not gaining weight? You don't want her to gain weight if she is lean, active and in good condition.

Lots of info on the premium foods here. You feed LESS of those types of foods, so even if the cost per bag is higher, the cost per meal is the same or less.