As I write this, I am walking. Sometimes I drink coffee too, though that's pushing the multi-tasking envelope. My walking desk is equipped with two cup holders. I've never used both. I have been writing at this desk for a year and a half now.

So what is a walking desk? A treadmill, with a platform for your computer.

The first time I heard of the walking desk trend, from Susan Orlean in The New Yorker, it struck me as pretty radical, challenging our traditional division of labor. When we work our brains, we rest our bodies. Flaubert said, "A writer can only work seated." (Of course, he said it in French, and it sounded even more authoritative.) On the other hand, Hemingway banged away at his typewriter standing up.

The problem with sitting is that it's too restful. The latest medical research says that in a chair your metabolism is almost as slow as if you were in a coma. Even if you run five miles at dawn, spending the rest of your day sitting down will undo all the good the exercise did, and you won't lose weight.

I was reluctant to add sitting to the list of pleasures medical killjoys have spoiled for us...until personal experience confirmed their research.

I returned from vacation to find I'd lost weight. More than five pounds. Surprising, considering I'd been enjoying the local cuisine and wine, and missing my usual three times a week exercise routine. The reason for the loss, I decided, was that I'd been on my feet almost all day, strolling the town and visiting museums and sights. Though I'd been walking slowly or standing, keeping out of a chair was enough to bring my weight down.

There are precedents to show that you don't have to sit at a desk to get work done. Winston Churchill and Admiral Nimitz both stood at their desks, which not only helped them keep alert but discouraged visitors from lingering, so they could get back to work, winning World War II in the Atlantic and Pacific theatres respectively.

Even more relevant to me is C.S. Forester, who used to mentally compose his Horatio Hornblower novels while taking long walks around the English countryside. He would complete the book in his head. Then he'd sit at his desk and quickly type it out.

I can do the walking and typing at the same time, though not very well. I can touch type, but I make a lot of mistakes. Especially when I'm shuffling along at 1 mph. Fortunately, we have spell check these days, so repair doesn't take too long. I do all my writing at the desk, except when I'm having a very hard time with a passage. It has long been my habit to switch to longhand at such moments. And my walking desk just won't permit cursive writing. It's not set up for it.

I also read at the desk. I can even go faster than when I'm writing, though I've never touched my machine's top speed of 4 mph.

The big question: have I lost weight? Yes. I'm running about ten pounds lighter than I did before the desk. Some changes in diet and exercise routine have contributed, but it's mostly the desk.