Dietitians can use an indirect calorimeter to measure your metabolic rate or the number of calories you need per day. It is a quick and inexpensive test.
The Medical Nutrition and Nutrition Entrepreneurs practice groups of the Academy of Nutrition and Dietetics would be able to test your metabolism using an indirect calorimeter. Dietitians often have their own private practice nutrition counseling services in addition to services provided in a clinic or hospital. You can find a dietitian at the Academy of Nutrition and Dietetics. Include your zip code or city/state, the type of service you want (individual consultation) and expertise needed.