In previous generations food was scarce and many people fasted during the week at least 1 or 2 days and shabbos was the only day they ate, not that they ate so well, but they ate decently.
Today we eat well during the week and then we pig out on shabbos. And tradional shabbos foods are fattening full of oils and other unhealthy stuff and today not only do we eat 3 meals on shabbos, many times we eat 4 meals (Some Shul kiddushes are themselves large feasts) While some will condem me for this, if I know there is a large kiddush in shul, we dont really eat lunch at home, Its just too much food