Pushing 40, I have a different philosophy on keeping fit. I try to aim only for things I know I can sustain long-term. Body building is not one of those. Neither is triathlons, or adventure racing, or whatever else that requires more than a minimal commitment of time.
Nope. I just run 30 minutes, three days a week, and then participate in a "Hash House Harriers" run every weekend, which is like a longer and more strenuous run., followed by beer drinking. You can substitute "play basketball, soccer" whatever for that. Just something that's fun and physical, and serves as the motivation to stay fit. Once in a while I ride my bike, too, but it's getting harder to find the time for that now that I have kids.
I know the value of weight training for losing weight, but I can't sustain going to the gym either, so I do crunches, push-ups and pull-ups almost every morning to help lose weight and maintain a modicum of upper body and back strength. I hardly ever have back problems as long as I keep up with the 20-minute morning workouts.
As far as food goes, I am actively trying to eat less, and eat more vegetables and avoid fatty stuff. My diet sucked for years and I'll probably pay dearly for that. I have a deal with our housekeeper right now (one of the perks of living in America's own banana republic) that if I can drop below 180 lbs (from 190) by Christmas, she gets a big bonus. She's from the Philippines and is always skinny, because she eats practically nothing but vegetables, rice, and tiny strips of meat. And then she cooks pizza or fried chicken for the rest of us. Well, not anymore - I'm eating like she does now, and so far I'm at 184 after only 3 weeks of it.
Supplements? I'm kind of fond of barley. And hops. :beerchug