We sit a lot these days. Not everyone, and not all the time, but as more and more of us are going to desk jobs and sitting in front of a computer all day there are health risks associated with that. 

But there's a simple way to fight those sedentary health risks - stand up! That's right, the simple act of working while standing up can promote better ergonomic health as well as, get this, BURN CALORIES. And we all like to burn more calories to try to get to that ideal weight, don't we?
Stand Up Desk Kathy
It's very hard to calculate just how many calories are burned while working at a stand-up desk. We're all built a little bit differently and we all fidget or move about at different levels. But the best estimates are that we can burn up to 50 calories more per hour by standing rather than sitting!
That might not seem like a lot, but even if you stand for half of your work day, four hours, that's 200 extra calories a day you're burning. That's 10% of a 2000 calorie diet and easily an extra bottle of beer, a soda or even a twinkie that you're burning off (those all have very roughly 150 calories each). Just by standing. 
Standing at your desk while you work also leads to more fidgeting movement. There's actually a name for this and it's "non-exercise activity thermogenisis" - aka NEAT. NEAT is basically all those everyday movements like making a gesture, fidgeting, shivering, a nervous leg bouncing up and down, that sort of thing. If you've ever stood at your desk, you might find that you're more prone to move around (especially if you're on a call) or to sort of dance a little bit while you stand. Me personally, I find it much more conducive to walking over to another part of the office and striking up a conversation rather than simply emailing or instant messaging a co-worker. And all of those movements add up and can contribute to hundreds more calories burned each week
Most of us sit enough while at home anyway. Throw in the time spent driving to and from work, especially if you've got a long commute, and we have a lot of sitting time. Another of the advantages of working at an adjustable height desk is that if you stand for most of your work day, you feel much better about sitting at home. It's sort of a reward and you feel justified in relaxing a bit. Not to mention that you've probably burned enough calories to have your favorite calorie-rich drink or snack and not feel guilty about it!
Adjustable Height Desk
And the more we stand the healthier we are - within reason. You don't want to stand all the time, as there are health risks with that as well. As Dad used to say, "everything in moderation"! But there are very serious health risks that come with sitting for 8+ hours a day. Sitting can compress the spine as well as tighten the shoulder, neck and chest. It's compounded when you're sitting in a badly designed chair that has no ergonomic value whatsoever. 
A sedentary lifestyle is just no good for us. As humans we just weren't designed to be put in a sitting position for hours on end. Blame whoever or whatever you want for it, but we are made to walk upright most of the time. Just look at the human body: 4 long limbs that are made to walk, run, throw, jump, etc. Whatever your beliefs are on how humans got to where they are, it's hard to fathom that our bodies are made to to sit in a chair - it's just an awkward-looking position if you think about it.
Even gym-rats who run and workout almost every day still have risks if they spend a large part of their day sitting down. Our increasingly sedentary lifestyles are the largest reason for our growing rate of type 2 diabetes, obesity and cardiovascular disease. It's important to note here that this is mainly for the first world countries like the US, UK and Australia. Third world countries don't have these types of problems anything close to the way we do. The single best solution for your health is a stand-up desk.
So as Bob Marley once said, "Get up, stand up!" - for your health, your waistline, and your overall well being!