Why do you need to "burn" any calories and boost your metabolism? If you care about longevity, you need to actually slow down your metabolism and restrict your caloric intake. Walking 30-45 minutes a day in the park is good enough - most geniuses in the past had the evening walk (30-60 minutes) as a common theme. Also, you don't need a fancy desk. Just take breaks and walk.
"Why do you need to "burn" any calories and boost your metabolism? If you care about longevity, you need to actually slow down your metabolism and restrict your caloric intake."
That's why it's called the exercise paradox[1][2], or the athletes paradox. Or whatever. The point is, you are correct - exercise increases your total metabolism and you eat more and burn more. But exercisers live longer and healthier and do not seem to pay the oxidative price for their increased metabolism that it appears they should.
What is the definition of "exercise" though? Running marathons and tens of miles a day? I never said that sedentary lifestyle is good, but more (when it comes to exercise and anything) is not necessarily better. Strength exercise is nice, but my concern with it is increased caloric needs (due to increased basal metabolic rate) and also - growth factors such as IGF-1. When I see people jogging next to cars exhausts for "health" here in Orange County under the skin-burning sun, I really get the feeling that most people are out of their minds nowadays.
There are alternatives. Once you get use to it, it's actually not a problem. The only issue is people who are prone to temptations. I have trained myself to seek pleasures outside of food and food to me is just a necessity, not a source of pleasure, and I don't have any internal struggle anymore and the only problem now is people who don't know me and who keep insisting that I try this or that. And, of course, the wasted time to explain my eating habits to people - 2 meals a day within 8 hours, and so on.
However, many posting here are interested in the weight-management effects of treadmill desks.
If you are doing heavy caloric restriction then you probably don't have a weight management issue. It's worth noting that the longevity-effects of caloric restriction seem to start occurring at very restrictive levels of consumption, and few have the self-control to stay at that level for decades (which seems to be what is needed).
Intermittent Fasting and the 5:2 diets are good compromises. My concern with too much exercise is the tissue wear and the oxidative stress associated with aerobic exercise. There are studies that walking for 2 minutes every 20 minutes negates the negative effect of sitting. I personally tried 25 minute sitting work + walking for 5 minutes (which actually increases productivity when you stop staring at the screen without a break).
