Studies show that raw, local, fresh, organic fruits and vegetables retain the highest levels of nutrients, followed by fresh non-organic produce. If fresh fruits and vegetables are not available, fresh frozen is the next best choice, with canned or boxed coming in last. In general, fresh is optimal and processing minimizes nutrients. The greater the shelf life of a product, the less live nutrients it contains. Consider replacing canned or boxed foods with fresh foods to increase nutrient content.