hour walk at lunch
There used to be a younger woman at work who was very overweight (I'd estimate somewhere around 350 lbs). She'd also wear clothes probably two sizes too small for herself. Guys in the shop would constantly make fun of her (behind her back), etc. I'd feel kind of bad because I'd laugh at the jokes, and at Lunch you'd see her walking laps around the parking lot.
But then of course for the mid morning break, she'd have a frozen hamburger and two corn dogs from the frozen food vending machine, and would always have a non-diet soda two-liter sitting at her work station, so I stopped feeling bad.
So remember... Walking doesn't do sh*t if you still eat crap like that.