“Eat for what you’ve done, and for what you have to do” - Christian Thibaudeau
That’s what I think of when I think about “eating clean.” In my mind, to eat clean means to only eat things that are helping you achieve your goals.
Eating “dirty,” (can we call it “messy” instead? As in “not very well-organized?”) in my mind is choosing food that doesn’t fit with your plan because of convenience, cravings, poor planning, etc. So if you’re on a ketogenic diet (a no/low carb diet) but have a bowl of organic, free-range fair trade non-GMO brown rice for dinner, that’s a “dirty” meal, even though there’s nothing inherently wrong with that food… It’s just wrong for what you’re doing.
Likewise, alot of people would consider eating a block of cheddar cheese melted onto bacon strips to be a “dirty” meal, but for our hypothetical keto buddy, that’s actually right in line with his dietary goals.
For most people, processed foods and simple sugars are not ideal for achieving their body comp/performance goals, so they are widely considered “dirty…” But tell that to a bodybuilder deep-throating his third Snickers bar backstage, and he’ll just shrug.