Yes, how about taking pictures of a bunch of 40 year old marathon runners and putting it next to a picture showing a bunch of 20 year old overweight accountants

Yes, how about taking pictures of a bunch of 40 year old marathon runners and putting it next to a picture showing a bunch of 20 year old overweight accountants and then ask people to guess the average age of each group? That should be pretty simple and covers at least the "looks" claim.