Should I be worried that my boyfriend is shallow?

Me and my boyfriend have a normal relationship. when we first started dating I thought the world of him but since its been a year I've been noticing a few things. On one of our dates he stared at a girl who walked by and she was thin a pretty. But when a heavy set girl walked by he paid no attention. ? (I thought she was very pertty) I asked him about it and he said He doesn't like big girls because he doesn't want to get squashed. Why do some guys do that? And how did I fall in love with someone like that?
Should I be worried that my boyfriend is shallow?
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