No, it was stealing. And they horribly mistreated the natives following settlement. Early Americans were selfish. But that’s how history goes.
The limiting factor that can involve a person's feelings about his own weight or ability is : Motivation
in most cases, the only thing that greatly affect the self confidence of an overweight person is their own motivation. Whether it's the motivation to get out from their current state or the motivation to focus on their goals while ignoring other's negative feedback,
hope this helps
Absolutely not. Human development is another branch of biology, and in order to understand it, people need to learn biology. Since David hates biology, this is not an option for him as he would have to go through similar things.