The British supermodel - who married The Kills rocker Jamie Hince on July 1 - is said to be on a mission to get healthy on her honeymoon so she can try for a baby as soon as the couple return from sailing around the Mediterranean on a £10 million yacht owned by Topshop boss Sir Philip Green.
A friend of the star said: "Kate peaked at her wedding with alcohol, cigarettes and bacon butties, but Jamie wants her to become healthier as they try for a child.
"Kate`s gone to the Med equipped with wheatgrass, barley grass and fish oils, with a view to getting pregnant when she comes home."
The 37-year-old catwalk beauty - who already has an eight-year-old daughter, Lila Grace, with former partner Jefferson Hack - is keen to show spouse Jamie she can live a healthier lifestyle.
The source added to the Daily Star newspaper: "Jamie adores Kate and wants her around for a long time. She hasn`t completely cut out the booze and cigarettes just yet, but this is definitely the first step and a new side to married Kate."