You can always link them to FitDay.com
Your class can track calorie consumption, calorie burning, weight loss goals, and various aspects of their physical fitness. By entering all food and beverage consumption into the site, users maintain a food diary that tracks variables such as calorie, fat, carbohydrate, mineral, and vitamin intake.
The site also contains an extensive nutritional values database, and also provides for the tracking physical activity.
I think you are dipping into a territory where you may not qualify to add that component to your classes. (I could be wrong) But, I would suggest working (partnership) with a company, organization to offer a package that will significantly benefit your client as well as your partner. This would not only help your clients, but should stimulate business for yourself.
FUel the Movement,