Pippa Middleton's fitness mantra revealed; what diet plan is she borrowing from supermodels?

One of Pippa Middleton's defining traits is her love for fitness. Kate Middleton's younger sister is regularly seen working out and when she isn't in the confined environs of a gym; she is cycling her way to Brighton from London, or taking part in a marathon in Kenya. The latest news suggests that Pippa has perhaps introduced a "secret weapon" that could improve her diet plan.

The Duchess of Cambridge's younger sister was seen at fitness instructor James Duigan's Clean and Lean Café in Notting Hill. According to a People Magazine report, Pippa, 32, browsed through Duigan's food supplements, including the Body Brilliance powder, which is reportedly used by supermodels.

The vegan supplement, nicknamed as the supermodels' "secret weapon," contains green tea and guarana, which help the body burn fat at a much faster rate. A Daily Mail report added that she also seemed interested in Ultimate Clean Fibre blend and Beauty Food mix, which cost around £50 a pouch.

Duigan, who has trained models such as Elle Macpherson and Rosie Huntington-Whiteley, is reported to have a different approach to health and fitness. His recently opened health café in London has oxygenated air and vitamin D that is produced from the light.