While working as a part-time personal trainer as an undergraduate student, Jordan Etkin created exercise plans with lots of variety for new clients.

The approach helped engage and eventually hook her clients into increasingly self-motivated and less-varied routines.

To keep beginners committed to a goal and coming back to me, I found it effective to mix different exercises, with little repetition, into their sessions. As these clients progressed, they were satisfied with less variation and more repetitions in exercises they became comfortable with,” Etkin says.

As a Ph.D. candidate in the University of Maryland’s Robert H. Smith School of Business, Etkin has applied her exercise-training insight to analyzing how consumers choose weight-management products to get in shape.

The results are in “The Dynamic Impact of Variety among Means on Motivation,” to be published in the Journal of Consumer Research in April 2012.

With her Ph.D. advisor, Associate Professor of Marketing Rebecca Ratner, Etkin tested her theory on undergraduate students in a set of related studies involving fitness goals and variety packs of products such as flavored Power Bars, protein powders, gels and shakes.

People who said they weren’t making much progress toward their weight loss goals found that using many different kinds of products spurs their motivation levels. The opposite resulted when they were closer to their goals. Once they were close, less variety did a better job at keeping people on track.

When they’re far from their goals, consumers want variety. It helps them feel more confident by giving them many distinct ways to pursue their goal,” says Etkin.

As the consumer closes in on the goal – for example, those last five pounds Z- he or she is more motivated to work harder and is also willing to pay more for a set of products that is less varied. Such willingness to spend – a secondary effect of motivation in both stages of consumer behavior in the study – is a big plus for retailers. And Ratner suggests a simple approach for them to capitalize further.

Etkin’s assertion that variation affects weight-loss consumers further stands to affect marketers and retailers in their approach to selling products to consumers and to the messaging they include on packaging, in stores and in advertising.

If you’re the consumer new to weight-loss products and deciding it’s time to shed about 25 pounds, envision yourself in the gym as a new fitness client of Etkin. She may start you on a highly varied cross-training workout, rotating from the treadmill to sets of crunches, bicep curls, and leg curls, and over time, as you lose weight, she may tailor your program to include more similar exercises.

Likewise, you should approach a nutrition program with different types of protein shakes, powders, and bars. As the pounds begin to disappear, you’ll likely identify and feel confident about a narrowed variety of supplements that work best. If so, you’ll know you’re on track to reaching your goal.