The answer is very simple: I stand at my desk at work. I eat standing at the bar in the cafeteria. I am on my tummy when I use the computer at home. Today I am visiting the p-doc and will be standing in public transit for more than 1 hr each way. I only sit in meetings, when visiting someone, or when eating out somewhere where there are only tables, no bar. I do not have many meetings, so on most days at work I just stand. It was difficult in the beginning but later became second nature. Of course, I sit on my bike for about an hour a day. But that is still not what is called "prolonged sitting" (=>3hrs a day)

When I was still sitting at my desk, I had intermittent piercing back pain below the left shoulder, at 7. When I started standing, the pain level went down to 1-2. Now, I have no pain - zero pain, without medication, massage, or physical therapy.

Many companies in the Bay Area have ergonomics departments that offer standing desks. In the rest of the country, it is still not common. But you can use your laptop lying down and that would cut down on the amount of sitting. It is not that standing per se is so great - what helps is NOT SITTING. Sitting is really bad for us and causes obesity among other things, plus shortens our lifespan by 2 years.

If you are allergic to milk (and other dairy - cheese, too?), I would take Calcium + vit D supplement. You do not want to risk brittle bones. Now that you mentioned that I also realize that standing works against gravity and thus helps prevent osteoporosis.