Can you just make the choice to solve P versus NP? Or climb K2? There's a lot of factors that affect a persons ability to make any choice. Willpower, knowledge and experiences, time, intelligence, etc.
There's thousands of factors that influence you making that choice, some factors in your blood, some from your childhood, and some from how your day went.
I'm very lucky that the stars aligned, so I don't have to try at all. Really, zero effort.
Others have to try very, very hard every day of their life. They need to think about what they're eating constantly. Do you know when I think about what I'm eating? Never. I just eat whatever I want, whenever I want.
What other factors influence that outside of you making the choice to eat something?