Along with listening to their bodies, I want my kids to understand that one size does not fit all. Just because their friends love cheese doesn't mean they have to. Some people tolerate dairy and gluten well, and others do not. There are many people who tout a specific diet, claiming it is the only way to eat. It may be for them, but that doesn't mean it is for everyone else.
For instance, some of us need meat; others are better without it. Some, like me, get along fine without it for decades, yet when I was pregnant and nursing, my body started demanding it again. I had to listen to my body and not allow the statement "I am a vegetarian" to trump my body's concrete cues.
I have one child who has never been able to take an antihistamine. Baby Benadryl used to make his heart race and keep him up through his nap and bedtime. After more than a decade, I recently tried it again when his allergies escalated, and he was amped up, restless, quick to become frustrated and slow to sleep. When he stopped taking it, his temperament returned to normal immediately. This is something I want my son to know about himself so he can be thoughtful about what he puts in his mouth and recognise negative side effects when they appear.
So when my daughter tells me she is listening to her body, even if it's nothing more than a ploy to get out of eating dinner, I am going to respect it.
Then perhaps when she is older, she will have the intuitive sense to take deep breaths before an exam, or to eat when she is hungry and put down the fork when she is not. Maybe she will even listen to alarms in her gut when her friends are doing something that doesn't feel smart, or follow her passion when settling on a career.