Easter of course represents spring and the celebration of new life for most Christians in general, but as new life through Christ. Rabbits became associated with Easter because they breed so quickly especially in the spring; new life. Easter comes during spring and celebrates new life. The Christian meaning of new life is of course through Christ but eventually the two ideas merged together, probably in the name of monetary profits! There’s even more to this story but I’ll stick to this short version for now.
As a dieter you might think of this holiday as a way to literally create a new life for yourself with healthier eating habits and lifestyle. Sure, it's a bit of a sacrifice at times to be dieting and changing your lifestyle, but becoming a healthier and happier person is certainly a new life and is surely worth the effort!