Obesity, with more tissue to perfuse and less lung space to use, also predisposes to altitude sickness. Being cold in addition to the altitude aggravates the situation further. And for some reason women are more apt to suffer than men. The best prevention is to just allow oneself time to acclimatize. In other words, plan a couple of days to just sit and do nothing when you first arrive.
Protein increases ones fluid requirements and diminishes the tolerance to cold.
Avoid alcohol and, despite insomnia, avoid sedatives as all of these diminish respiration and delay the time to recovery. These are harsher on the system, however, and have more side effects so are best saved for emergencies. Drinking a lot of fluids also helps to prevent mountain sickness and the best treatment for the headache is aspirin. One folk remedy commonly recommended in the Andes is coca tea. Brewed from the leaves of the same plant from which cocaine comes, it is reported to prevent altitude sickness about two thirds of the time.