Pippa Middleton has shared her healthy-eating secrets.

Pippa, the sister of Kate Middleton, the Duchess of Cambridge, has opened up about her most recent adventure; a four-mile swim across the Bosphorus Strait.

As well as spending plenty of time in the pool, the 30-year-old socialite maintained her fit body by eating lots of lean protein and complex carbohydrates.

She explained: ''In the run-up to the swim, I didn't really change my eating habits. For any sporting challenge, I always try to eat a healthy balanced diet when I'm training. To maintain energy I try to eat more protein, particularly fish or chicken and wholesome carbs such as brown rice, lentils or quinoa instead of bread, potato or pasta.

''A lot of people swear by carb-loading in the run-up to an event but it just doesn't work for me, so I just try to up my protein intake and try to sleep, eat and drink well.''

However, unable to resist the food in Instanbul, Turkey, Pippa and her parents Carol and Michael Middleton and younger brother James - who was also participating in the event -enjoyed a seafood treat the night before the mammoth swim.

She shared: ''The evening before the race we all ate out in a traditional fish restaurant on the shores of the Bosphorus. As we devoured a Turkish seafood meze of stuffed mussels, calamari, fish croquettes and octopus, I did wonder whether this was such a good idea the night before our swim.''