Many people are under the impression that you cannot buy healthy foods at Costco. While there are a lot of less healthy choices there, I buy a majority of my healthy foods there. This is what my list consists of on most trips.
*For the past two years we have bought half of an organic cow, so I only buy beef at Costco if we run out. During spring and summer I have a lot of spinach and mixed lettuce (which is super easy to grow) in my garden, so those are things I depend on Costco for in the winter. If you do not have some of these items in your Costco, ask the manager. They may be able to stock it if there is enough requests. It's couldn't hurt to ask. Hope this list helps!