Theory: for me a healthy diet is lots of homemade soups and vegetables - salads rarely cut it for me - I grew up doing a lot of physical exercise outside and you can't spend 6 hrs a day working in cold weather and looking after animals on a salad without fainting - for that amount of activity you need to eat a healthy diet. I believe what you grew up on, wherever you are from, if it wasn't processed and was freshly cooked is probably what your body operates best on.