NutriSystem has more than doubled revenue to bring in US$132.63m during the second quarter of 2006, compared to $40.94m for the second quarter of last year, and announced an endorsement deal with Hall of Fame quarterback Dan Marino.

The company, which provides weight management and fitness products, has increased operating income to $31m in the second quarter, from $7.1m in the second quarter of 2005.

"NutriSystem achieved strong revenue and earnings growth during a seasonally slower quarter," said Michael Hagan, chairman and chief executive officer. "We're excited about the progress we've achieved thus far in reaching the male market, and the men's segment represented over 21% of all new customers in the second quarter."

NutriSystem executive vice president and chief financial officer James Brown said: "We believe marketing of the men's programme raised our overall customer acquisition cost in this quarter, but we generate more revenue per customer from men, more than offsetting the higher customer acquisition cost."

In its outlook, the company estimated that revenues for the third quarter would be between $135 and $140m, an increase of at least 100% year over year, and between $525 and $535m for the full year.

"The confidence that we have in our business and its potential has only grown during 2006. Our year-to-date customer acquisition cost for our core demographic - women - has declined compared to the same period last year," Hagan added.