MPs last night defended the RAF’s “tip… It comes after an RAF survey last year found 4,272 airmen and women classed as clinically obese, the highest level ever recorded. Each F-35 plane has been equipped with a seat capable of ejecting a person weighing nearly eighteen stone, documents show. In 2014, the air force ordered overweight crew to adopt healthier lifestyles amid fears that too many were not “fighting fit”. Defence sources said the seats had been designed to cope with the “increasingly diverse physical profile” of modern aircrew. Britain’s new fighter jets have been fitted with super-boosted ejector seats because RAF pilots have grown heavier in recent years, the Telegraph has learned.