Great post from the terrific blog, Dances With Fat: Health Comes in All Shapes and Sizes.
Put the Focus on Health: Research shows us that while movement is really bad at creating weight loss, it is really good at supporting health. Instead of selling people a cardio room and a bag of magic weight loss beans, your gym should be educating people about the actual possible benefits of exercise. I would suggest starting by offering to measure things other than weight. Offering tests like VO2 Max scores, blood panel, strength, stamina, flexibility etc. People could choose the baseline tests they want at the beginning and then take them again three. six months in etc. to see if there are any changes. That way people wouldn’t think that exercise is “failing” just because they aren’t losing weight.