All people have bodies and all people are vulnerable to angst. Beauty standards can sometimes exclude people who are not quite slim, tall, or beautiful, so why not have a character angsting about their body? But body image is not always negative, and happily, we have tropes about characters who are fine with, and even proud of what they have, even if it is supposedly negative.
Compare with ObsessionTropes & PrejudiceTropes.
'''Positive Body Image'''
'''Negative Body Image'''
* DefiledForever (often has overtones of this)
'''General Body Image'''
'''Reactions To Body Image'''