In which case, try to introduce a little more starch into your diet.  Foodstuffs with a high iron content are also good for rigidity.  If you don't start to notice a difference within six weeks, then I would suggest my specially formulated porridge mixture, which consists of a generous portion of medium oatmeal, full cream Jersey milk, a pinch of salt and three parts sand to one part cement.  I guarantee it will firm you up in no time.