She’s still super-svelte by anyone’s standards, but the Duchess of Cambridge has put on 3kg in the past couple of months after being warned by palace courtiers that she is too thin and risks setting a bad example to her millions of fans around the world.

Kate, 30, stepped out in Oxford last week sporting a slightly fuller, more shapely figure, which friends tell Woman’s Day is a result of relaxing her strict eating regime, and regular exercise sessions with her sister, Pippa Middleton, to help build up muscle.

“Kate got so thin that she started popping up on pro-anorexia websites and being hailed for being so skinny,” one friend explains. “That’s when her aides suddenly became concerned and a quiet word was had.

“Being a role model is very important to Kate and she is aware of her impact. She doesn’t want to put out a negative image, but it’s been hard, because she is naturally thin. She never regained those few pounds she dropped with all the stress of the royal wedding.” In recent months, Kate has put extra focus on her health, eating more carbohydrates, and ensuring each meal contains a portion of organic protein and lots of vegetables.

Read more including how Kate is spending her nights while Wills is away in this week's Woman's Day on sale Monday February 27, 2012.