the third option would be the best choice because it appears on a national health organization website
I think this means:
If it's possible for a human being to do something, don't just say that he can't, just let him try, give him a chance.
Fast food is convenient because it is cheap and it’s prepared ahead of time and you don’t need to cook it. You just order and enjoy the meal especially if you don’t know how to cook. It saves time and energy.