I’m basically in the same boat as OP except opposite job direction (went from labor to desk). Over a decade of manual labor with no scheduled lunch breaks has left me with poor eating habits. I tried meal prepping but ended up doing what your friend was doing, loading up on fruits and vegetables with some protein. Wouldn’t eating stuff like buttered potatoes and drinking a couple glasses of milk everyday lead to heart problems? Or would cardio and being underweight basically cancel that out?