Barcelona ace Lionel Messi's personal doctor has revealed what the superstar eats to keep himself in shape.

His doctor, Guiliano Poser, has provided an insight not only into the Barcelona star's training methods, but also the diet that continues to fuel him in order to perform at a high level.

"Water, good olive oil, whole grains, fresh fruits and vegetables that have had pesticides used because they create no harm to the body," he told Mundo Deportivo. "Nuts and seeds are also very good.

"No sugar though. It's the worst thing for your muscles. Even refined flours are a big problem, basically because today it's very difficult to find a grain of healthy wheat that is untouched."

"Salt is fine but in moderation, because the muscles and the body needs it in general," he added. "Leo eats meat in moderation too, much less than the amount typically eaten in Argentina and Uruguay because it is difficult for the body to digest it."