Beemerboy (& Scottwax)- I just knew we'd hear from Scottwax when I saw your post! I bet your locale is great for a biking enthusiast.
chet31- A few thoughts (and again, I hope I don't come across as argumentative):
First, let met me say that if somebody can cut out a bunch of calories without depriving himself of some needed nutrients, then sure, oughta do that! Empty/excess calories just don't make sense any more than running an engine on an overly rich fuel mixture. So I don't think you and I are actually in disagreement at all. That said..
When a friend of mine claimed that "it's easy for you to be in shape, you're retired...", I thought of how I now exercise *FAR* less than I did when I was teaching, maybe one-third as much if even that. (Heh heh, I also thought how it's nice to not have to do a workout at 4AM any more!) To prove my point, I decided to keep track for a month and it turned out that I average just under 20 minutes/day over the course of a few of my ten-day cycles.
OK, that's just me- I have my routine all figured out and I have all my exercise facilities here at home. Guess that last part is a wildcard, huh?
But IMO you can get an effective workout done in far less than one hour or else you're not working out very hard- I mean, how long can you do max-effort 90-second Time Under Load sets with weights; how long can you run windsprints?
I'd hate for somebody to use my friend's excuse and think there's no point that that exercise stuff if there aren't hours available. If every sedentary person did five minutes of Burpees every other day the world would be a fitter place. Push ups, chins, body-weight squats (too easy? use one leg), there are a lot of effective exercises that can be done with virtually zero equipment.
My weight workouts don't take an hour any more, and I'm making better gains than when they did, and the most effective cardio workout ever studied (the Tabata Protocol, which is what I basically do on my "AirDyne day"), involves 3 minutes of both warmup and cooldown with only 4 minutes of actual "workout" in between them. At the end of that brief workout I absolutely couldn't do any more if my life depended on it. And yes, in the studies that workout resulted in better fat loss than longer, less intense, workouts.
IMO it's not about exercise *time*, but rather its *intensity*.
I guess I just kneejerk about even the slightest hint that somebody can get away with not exercising; as we age the body loses muscle unless it's worked pretty hard, and that leads to all sorts of, uhm...negative outcomes. I've known a lot of elderly people, and the "healthy but weak" folks weren't able to do a lot of things and seemed to suffer a lot more accidents. OTOH, I've known octogenarians who exercised that basically lived the same lifestyle as when they were younger.
Again, I think I'm not disagreeing with you so much as using your post as a springboard for discussing the "necessary time" topic.