But if an individual has already gone through formal training, online training can be useful as a reminder or to get recipes and nutritional tips, he added.

Sweet Potato, a Toronto-based nutrition and fitness company, makes Internet training available to those who are willing to meet face-to-face with a trainer once a month "to correct form, introduce variety." And e-mail with fitness "homework" keeps clients on the program the rest of the month.

"If a person is self-motivated enough, whether it be to pick up software or a book on exercise, if they're willing to go about it in a steady, safe way, then getting their exercise that way is better than getting no exercise at all," Macdonald said. "But the caveat is that if they have any questions or concerns they should seek out the help of a professional."

It's also important not to confuse personal training, where an expert teaches you how to properly use weights and equipment, with life coaching, where an expert helps with such things as stress management and eating patterns.