Home grown and organic, or at least natural, fruit and veggies are the best. You can be allergic to chemicals used in the growing of produce, even if you are not allergic to the product itself. If you can't grow any fruit or vegetables then visiting a local farmer's market works great, or even a health and natural food store in your area. If produce is grown within a hundred miles of your home, then so much the better. Long transport reduces nutrient value of vegetables and fruit.
I am trying one of those "grow your own vegetables upside down" container gardens, because I want to have it handy on the patio right outside my door. And, it's much easier to maintain that way as well. After visiting a famous theme park area in Florida many times, I was inspired by their huge hydroponic and misting and other unusual agricultural methods of growing produce, greenhouse. While I started my hanging upside down garden with a kit, I soon found that growing the seedlings from seeds does work very well, so I purchased one tomato plant as a starter. All you need to do is make sure that there is about a one inch hole in the bottom of a container and that you have a hook to hang the pot on, a few feet off the ground.
Use some of that coconut fiber and after popping the seedling plant in through the bottom, place a few pieces of the fiber over the roots, then potting soil. Hang it up, keep it misted watered, and feed sometimes. Supposedly, the tomatoes won't mind being upside down and will grow like weeds. You can also try this with cucumbers and a few other plants. Plants that grow off of a single stem then branch out, or vegetables or fruits that vine, should work great. We'll see what grows in the Summer. Make sure that the plants get appropriate, but not too much, sun.
There are dwarf fruit trees that can be grown in a small space and if you have a climate that is suitable for citrus or apples, then these plants should do well. It would be more difficult to grow bananas but many varieties of citrus such as oranges and lemons and limes and tangerines and even kumquats could be grown full sized, on a dwarf tree. If you are lucky enough to have a large garden then the regular method of growing your own fruits and vegetables will work great. It is some work, but a benefit is that you can get good exercise while you are at it. And again, if you have no space at all for growing healthy fruits and vegetables, then going to the local heath food store or market, will work out just fine.