16 Foods You Don't Always Need to Buy Organic. Organic food is growing more popular in the U.S., and for good reason. It's better for the environment and less likely to contain pesticide residue than conventional foods are. While pesticides protect plants from insects and disease, they may pose health risks, particularly if you consume large amounts of them. According to a 2011 Wageningen Journal of Life Sciences report, animal studies show that an organic diet can positively affect weight, growth, fertility and even immune function. But not everyone has access to or can afford to eat a 100% organic diet. Read on to find out which foods are less likely to contain a significant amount of pesticide residue, and are therefore safest to purchase as conventional (i.e. non-organic), if needed.