I was happy to see this: http://www.care2.com/greenliving/tai-chi-diet-depression.html.
Here's what the article had to say:
The University of Queensland, Australia has released an exciting study for anyone looking to lose weight. Researchers found that the gentle, yet powerful, exercise known as tai chi helps with obesity and excess weight, in a number of ways. The scientists discovered that tai chi:
Improves body mass index (BMI–an indicator for healthy weight);
Reduces the amount of abdominal fat and overall waist measurements;
Improves blood sugar balance–a critical element for maintaining a healthy weight or to lose weight;
Reduces high blood pressure;
Significantly reduces depression; and
Improves the body’s use of insulin (insulin resistance)–a significant factor for weight gain and diabetes, among other serious health conditions.
Read more: http://www.care2.com/greenliving/tai-chi-diet-depression.html#ixzz1Ed3KoKJM
In addition to Yoga, I started practicing Tai Chi about eighteen months ago. I love it. It's slow moving and thoughtful, but it's a perfect set of easy exercises to learn. What's so great about it, is because they're so easy, you wind up practicing them all the time (which you're supposed to do).
Here's how it works, at every class you little bit more of various "forms" (essentially a series of movements), and you're supposed to practice what you've learned in-between classes. The first form I learned took over a year to master (and it still needs a lot of fine tuning). I'm now working on learning my second form which involves a sword.
The dictate to practice (becuase the more you practice the faster you progress), means that you get a lot of extra movement in during the week. As I mentioned, it's pretty easy. You don't sweat, etc., so it's a perfect little "breather" when you're working. I like to practice ten or fifteen minutes prior to going to sleep.
So, I guess one of the main reasons why it helps in weight loss is YOU MOVE MORE, and anything that gets you moving is a good thing.