Women usually do that.
I don't understand why her eating habit such a big issue here. Her eating habit and appetite look completely normal. Every one has different taste, someone tries to eat healthy, someone eats everything. Someone eats a lot, someone eats much less than others. There are people who are vegans and vegetarians who got cancer. There are people who eat everything including junk food and they are healthy their whole life. Eating really doesn't matter much unless you have chronic conditions that cannot absorb nutrients from food, or diabetes, high cholesterol, some particular chronic conditions.