In response to:
“Oh but isn’t that processed?” Yep so is beer, wine, bread, pasta…processing isn’t what matters. Number of ingredients and whether you can pronounce them are not important either. What matters is nutritional content. That’s a fact. Not an opinion. Can we as a culture just get over this pseudoscientific food snobbery please? Thanks.
“What matters is nutritional content” perhaps, but I would be sure to add some caveats to that. We don’t have a complete index of nutrients nor their impacts on the body. For example plant polyphenols in berries, we’re just starting to understand1, and there is evidence that eating these nutrients in their “unprocessed” state is more effective than just eating the nutrients directly234. Why would that be? It’s possible that we just don’t know what all the co-nutrients are yet, but it is more likely that there are countless interactions between body and food that we haven’t even scratched the surface of explaining.
A second caveat I would include is that food is a “package deal”. You have to eat something. If you’re eating a lot of processed foods (or a lot of animal foods), the likelihood of you getting the nutrients you are talking about goes down5. Also, the likelihood of getting toxins that you don’t want goes up. For example, potatoes, which are generally fairly healthy when steamed or boiled, create acrylamide when cooked at high heat a la french fries6. So even if we ignore my first caveat for a moment, it can be misleading to tell people that how processed a food is doesn’t matter, because that will most likely lead them to get fewer of the nutrients that we agree are important and more of the bad things.
Given these caveats, if you actually want to eat healthfully, it makes more sense to step back and look at the whole diet, rather than individual nutrients. This means you’re basically stuck with epidemiological studies of populations, and dietary intervention studies, neither of which is capable of establishing a sure-fire causal relationship. However, the evidence from such studies is pretty strong6 in favor of eating more foods of plant origin and in less processed form23478.