I like your thinking, MP! My stepmom's always been tall and thin and I've always wanted to look like her. But a few years ago, I found out she's got higher cholesterol than my dad does- and daddy's pretty big. The stuff she eats is so rich, creamy and laden in fat that it's just clogged her arteries.
I may be 30 pounds heavier than her and five inches shorter, but my cholesterol is perfect. So is my blood pressure, whole blood count, blood sugar, etc.
So yes, unhealthy eating does catch up with you eventually. You might not necessarily be overweight or obese, but the inside will tell a whole different story.