Washington, Oct 10 Tom Cruise is so much paranoid about gaining weight that wife Katie Holmes has put him on a sex diet, say sources.

A source said: "Tom had been complaining about how hard it is to keep off the pounds, so Katie vowed to help him out.

"Katie read somewhere that you burn up 600 calories just by having sex three to four times a week. So she's told Tom to think about how much they'd burn up if they put daily sex sessions on their schedule!"

And apparently the Top Gun star is thrilled with 30-year-old Katie's plan, reports Contactmusic.

The source added to America's OK! magazine: "Tom thinks the sex order is the best part of Katie's diet plan, and he's promised to up the bedroom romps whenever they are in the same town, just for the sake of his diet!" (ANI)