With the advent of programs such as Overeaters Anonymous and Weight Watchers in the early 1960s, weight-loss programs left the confines of the home in favor of a form of group therapy. Men and women who couldn’t lose extra pounds on their own found solace and success with other like-minded individuals.

While these programs still are available today, new trends have given dieters the freedom to manage weight loss from their homes, and the Internet has made sure they’re not leaving behind the benefits of social interaction. Following are some ways health and dieting Web sites are using the knowledge gleaned from group meetings to change the way their members lose weight at home.

Immediately engage and motivate

To paraphrase Sir Isaac Newton’s first law of motion, an object in motion remains in motion unless something acts to slow it down. Unfortunately, human nature doesn’t often follow the laws of the physical world. A diet started today with the best of intentions might stop tomorrow unless something actively keeps it going. The first function of many weight-loss services is to provide that motivation through counseling or group meetings.

Understanding this, weight-loss programs Jenny Craig and Weight Watchers Online keep the initial momentum going for their new members by sending e-mail encouragement during the first few weeks of their respective programs. In both cases, the messaging cycle is automatically kick-started by the member sign-up.

“These e-mails get them engaged in the program and educate them on how to follow the plan online to ensure they’re successful,” says Alexandra Aleskovsky, senior vice president and general manager of New York-based WeightWatchers.com. “And it helps drive retention because the more successful and the more engaged the subscribers are up front, the longer their retention curves tend to be.”

Weight Watchers Online sends five e-mails in the first five weeks of its online program; Jenny Craig sends two in the first week, and one per week for the next seven weeks.

Trish Arellano, director of Internet marketing for Carlsbad, Calif.-based Jenny Craig, notes that the company’s e-mails include tips tailored to where the customer is in her weight-loss cycle, as well as links to video content exclusively available through the e-mails. The videos feature a celebrity spokesperson describing her journey through the program at the same point in time as the client receiving the e-mail.

Help members help each other

At the crux of programs like Jenny Craig and Weight Watchers is the concept of accountability through social interaction. Jenny Craig encourages its members to work one on one with a consultant, while Weight Watchers uses group meetings to share stumbling blocks and success stories. The rise of online social networks has made those types of interactions available at the click of a mouse.

Healthy-living community SparkPeople.com offers free tools, forums and content centered on setting and attaining weight-loss goals. Initially dedicated to providing tools for setting any type of goal, the Cincinnati-based site began transitioning to a focus on healthy lifestyles and weight loss goals in 2003.

In 2005, the site launched social-networking tools typically associated with sites like MySpace: customized personal pages, group pages and personal blogs. However, “ … unlike a lot of other social-networking sites, we don’t focus on getting people to make this their primary social network and get all of their friends to join,” says Grant Miller, general manager of SparkPeople.com. “We’re just a tool so people can more easily meet others like themselves online and support one another.”

As of October 2007, SparkPeople has registered more than 2 million members.

A typical SparkPeople user comes to the site because she wants to lose weight, but once she joins the service, she’s presented with many options, Miller notes. She can either access her personal diet plan or search for a SparkTeam focused on issues important to her.