Be very wary in the U.S. the term "natural" as it has no meaning whatsoever. You can put "natural" on a jar of Cheese Whiz if you like.
Frankly, I avoid brands that use "natural" because it tells me they want to lie to me about their product and I'm not playing their silly marketing game.
"Organic" actually does have a meaning. Certified Organic (look for the green oval) is even better.
I can tell you this -- I feel much better the more organic food I eat and it is tastier too. My liver is already on overload -- the last thing I need is to give it *anything* more to detox.
Odds are my little hospital episode a couple of weeks ago was due to eating non-organic food at my Mom's for several weeks. Funny, but I have most of my episodes when I'm at her house, even though I'm not getting anything I'm allergic to.
Some caveats, though. It's still important the stuff be fresh. You've probably seen organic areas where the food looks iffy? Well, it's lost many nutrients by then.
Also, buying local is better. The food is fresher and will have more nutrients, even if it isn't organic.
Also, I don't care for GMOs. I don't care if they are "safe" for us -- environmental studies have pointed out that many of them are not safe for the native wildlife, especially some beneficial insect populations.
As for fruits and vegs, some things are more important to have organic than others. I don't eat conventional strawberries, ever. Aside from the fact that almost all of them are GMO these days, they should be thought of as "pesticide sponges." I am less concerned about melons.
The time of growth when pesticides are sprayed and the ability of the plant to absorb the pesticide is everything. If it's sprayed when flowering, then the fruit will contain the pesticide. It isn't just a surface thing where you can wash off much of it.
If the rind or outside is fairly impermeable (like melons) and it's sprayed after flowering, it's less of an issue.