When it comes to fats, embrace olive oil. That's where you start. You can use butter when its flavor or luxury is really going to matter to you. Use peanut oil or grape seed oil for stir-frying (or any frying), use dark sesame or nut oil for extra flavor, and you really don't much else. --Don't worry too much about quantity. Don't start drinking oil, or eating fried food daily; but using oil for dressing or cooking is not a big deal, provided you are not eating many refined carbohydrates or animal products.