Why is my mom so anxious about my eating habits?

So I am 17, and no matter what my eating habits are and what my weight is, in the eyes of my mom, I am very skinny, unhealthy and in need of a good diet.

Growing up, I hated food. It used to take a huge toll on my family to force me to eat. And as a result, I used to be very skinny.

Now, I eat normally, and I am of a healthy weight. Yet my mom never ceases to look at me in my face and complain about how unhealthy and sickly I look, always offering to cook me something healthy.

Whether she is at work, home, or sleeping, she is always worried about my eating habits.