If you want a free metabolic self test there are a couple that I have gone through but the one I prefer is here at natural healthy yellow pages:

http://www.naturalhealthyellowpages.com/metabolic/self_test.html

What that will tell you is how to eat well according to your metabolic type, which has definitely helped me with weight loss

While searching around the web I also found a great question that asked if eating less slows our metabolism how can we lose weight when we are on a diet? Which of course is a great question and the answer is :

You touch an aching fact…our body is a genius machine that is built to save energy. When we loose fat tissue it stops sending a hormone named “Leptin” that is a one of the hormones that control our metabolism. The idea is to know this fact and continue with your diet as planed. A well balanced diet that is followed with regular physical effort will not loose weight as fast as it did on the first 2 months, but it’ll eventually do so. After loosing weight the important thing is to continue the life style you adapted until your body will regulate the amount of leptin it needs. Leptin is the cause people gain back their weight after a diet.

source : free medical dictionary

That was a great answer for me because now I know to just keep going through the weeks of no weight loss and eventually your body will start again.