"Do you want pizza?" I ask. She shakes her head. "Do you want to watch a movie?" She declines. What my 4-year-old niece wants to do most during our time together is share a healthy snack [1] and practice some yoga [2]. She curls herself into a yoga position and tells me that she only drinks plain milk because flavoured milk isn't as healthy before saying "Namaste" and effortlessly nailing her Vinyasa flow. She then tells me how she's embarked on a campaign to convince the other kids in her pre-k class to reject chocolate milk.

My 4-year-old niece doesn't have superhero self-discipline or willpower. The difference between us is that she remains curious about why we eat the food we eat, and if she doesn't receive a satisfactory answer, she just doesn't eat it. Sure, she enjoys the regular treat [3], but she knows that too much sugar causes diabetes. She prefers, instead, to quiz you on the value of the food you put in front of her. Will it make her stronger, faster, taller, smarter, healthier? If the answer to any of those questions is no, she'll take a hard pass and go exercise.

"Why wouldn't you want to exercise [4], auntie? It's fun and makes you healthy," she says. It's that simple. She finds it fascinating that adults need gym memberships and self-discipline to exercise, when it's so easy to find active workouts in her house [5], her backyard, and especially the playground. She likes to race, compete against herself, and cares only about whether she's gotten stronger or faster since our last race.

Her whole attitude made me wonder how (and when) many of us lose that healthy curiosity about why we eat the food we eat. Is it marketed out of us by fast food ads and bright and shiny packageing? Is it too late to reverse the convenient-food, nutrient-free junk we're inclined to choose? Maybe not. Maybe if we approach our meals and our workouts with a 4-year-old's simple curiosity, we can all learn something from the untainted children around us. "Why am I eating this?" "What can this food do for me?" "How will this workout benefit me?"

I'm not embarrassed to admit that a child is teaching me healthy habits [6]. I've found myself starting to incorporate her advice and ask myself "why" before I skip a workout or reach for a bag of processed food. Why wouldn't I want to go for a run today? It's beautiful outside, there's so much to see, and just think of how great I'll feel when I've finished.

Eating like my niece has also taught me a lot about portion control and distinguishing boredom from hunger. My niece, like most 4-year-olds, is never really bored. When she's hungry, she eats, and when she isn't, she doesn't. No matter how great something tastes, she doesn't eat until she's uncomfortable. She picks at her meals slowly and walks away from the table when she's no longer hungry. She would much rather play outside, throw herself into Downward Dog, or race around her backyard than continue to eat when she intuitively knows she doesn't need more food. And the beautiful thing is that it's not about looking a certain way to her. She loves feeling good and strong, and she does what she can to make sure she takes care of her body in the best way. She inherited that from her mother [7], but she's taught it to me.

Following a 4-year-old's health advice is actually really easy, and it's something that I intend to continue to do. She inspires me all the time, and by looking at the world through her eyes, health becomes much more about having fun than anything else. And I'm ready to have some fun.