Scarlett Johansson has laughed off speculation that she has embarked on a low-carbohydrate diet in preparation for her role in Iron Man 2. Tabloid reports suggested that the actress had lost around 14lbs working out with co-star Gwyneth Paltrow after becoming increasingly concerned about “younger, skinnier” competition. “The press is making something out of nothing. She is simply getting into shape for a very demanding, physical role in Iron Man 2,” the Daily Express quoted her spokesman as saying.