> Processed foods are much cheaper per calorie than "healthy" options.
> Instead of $0.50 worth of Doritos as a snack, I'm eating $1.50 worth of Greek yogurt and $1.50 worth of fruit.
I won't bother with currency conversion because we're comparing ratios.
50 cents here gets a third of a 200g bag of generic brand potato chips, so 360 calories. Doritos are probably at least twice that expensive but whatever. (The generic-brand sandwich cookies that are my personal vice, are cheaper yet. There's so much variation within these vaguely-defined food categories that I can't take the comparison across categories seriously.)
$1.50 gets probably a half dozen bananas here, at around a hundred calories per. Never mind the yogurt. (If you're buying fresh cut fruit you're simply doing it wrong.)
So if you're purely comparing calorie counts and finding yourself on less-calorie-dense options then yeah there's a ratio but it's still not as bad as people think. But this is still fundamentally committing a fallacy equating "less calorie-dense" with "healthy".
The same 360 calories from white rice cost me perhaps 15 or 20 cents (plus the time and energy to cook). I'm not big on brown rice but I'm sure I don't have to pay several times as much for it unless it's some fancy boutique thing. 360 calories from dried split legumes (packed with protein and fibre), similarly, are in the ballpark of 30 cents. Perhaps you don't "snack" on those things, but you get the point.