Living on dried food like beans and rice is a recipe for malnutrition.
You've heard of scurvy, right? Among other things.
http://www.pbs.org/newshour/bb/widespread-childhood-malnutri...
"I'm able to avoid presevatives because I cook a lot of good myself, from scratch."
Yeah, well, not everyone has a Whole Foods down the block, or could afford to shop there even if there was.
I don't think the food scarcity in Guatemala is relevant. Kale and carrots and dairy products can be obtained for pennies a day, and meat is subsidized and readily available in raw form.
If you want to see the other side of that, which is abundance of low quality, toxic food, check out the various odd Heath problems that are on the rise in the US such as childhood obesity, diabetes, unexplained hyperactivity and so on.
Manufacturers can choose less harmful presevatives such as vitamin E vs bha/bht, but choose not to for their own economic reasons.
I'm able to avoid presevatives because I cook a lot of good myself, from scratch. This involves cooking vs say, watching tv and is actually cheaper than processed or fast foods. Cooking rice and beans from scratch is not first world privelege - eating synthetic compounded beans from Taco Bell is, actually.