NutriSystem ( NTRI) posted a strong second quarter and boosted full-year guidance.But shares fell 6% late Monday after the company said operating chief George Jankovic will leave to attend to family health issues. The Horsham, Pa., diet company said Thomas Connerty will take over as chief marketing officer and executive vice president of program development. CEO Michael J. Hagan will take Jankovic's president post. "This was a very difficult decision for me to make, but at this time I need to prioritize my and my wife's families who reside overseas and who are currently going through serious health-related problems," Jankovic said. For the second quarter ended June 30, NutriSystem made $19.8 million, or 53 cents a share, up from the year-ago $4.3 million, or 12 cents a share. On an adjusted basis, excluding certain costs, latest-quarter earnings were 56 cents a share, a dime better than the Thomson Financial analyst consensus estimate. Revenue more than tripled to $132.6 million, breezing past the $123 million Wall Street target. "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," Hagan said. "This has exceeded our expectations and with the recent announcement that Hall of Fame quarterback Dan Marino has joined our team, we're even more optimistic about our ability to further penetrate this largely untapped market." NutriSystem guided to third-quarter earnings of 47 cents to 50 cents a share on revenue of $135 million to $140 million. Analysts were looking for a 44-cent profit on sales of $120 million. For the year, the company expects to make $2.04 to $2.10 a share on revenue of around $530 million. Analysts were looking for a $1.87 profit on sales of $502 million. Shares of NutriSystem, which is up more than fourfold over the last year, rose $2.85 in regular action Monday before falling $5.10 in late trading to $62.70.