In general, the Spanish diet falls into the larger category of the Mediterranean diet, where such ingredients as olives, olive oil, garlic, tomatoes and onions prevail, as do fish and seafood. And, as I'm sure we have all heard, the Mediterranean diet is one of the healthiest in the world. Serrano ham is fatty, but it's actually not that high in cholesterol, and it's lower in sodium than most cured hams. The Spanish tend to eat late at night, but they don't go straight to bed afterwards. They tend to go to bed late as well.
Potatoes are just a starch that is used to accompany a meal.
If they're fried in olive oil, they have no cholesterol. Like anything else, the few facts I mention above have to be taken in context with the diet as a whole. I believe it's due to their total lifestyle, which typically includes a balanced diet with an emphasis on fresh foods, rather than processed, packaged ones, and a moderate activity level, which usually includes an enjoyable daily stroll through town. English and Spanish. Spanish and Catalan.