Love the pic...very cute . but on a serious note My Alvin is overweight...and I have changed his diet but he gets irritated when he doesn't have an ample amount of food...what to do?... he hasn't always been overweight and gets plenty of exercise,and a nutrious diet, only thing that that has changed is .. he is getting older...4 and a half years old now..but considering they can live to be 18 years old.. 4 and a half is not that old??..>> any ideas on helping him slim down mjs ??