I have another phenomenon for you. I'm software developer, but barely holding up to my current 250lbs. Because:
1. local cafeteria gets worse with each change of servicing company - small portions, unimpressive food and prices higher than a cool diner place nearby.
2. Office located in a middle of... "nowhere". Not much good places to eat in vicinity. Need to walk about a mile in one direction to get to McD - I'm too lazy for that
3. No snacks for staff... only coffee. Pretty much enough to keep programmers fueled up.
4. I'm single and don't like to cook much or visit restaurants after work alone... so not much food around at my home either.
And voila! Your "office jobs" tricks don't work on me