Answer:
1. A specific culture has different calories and different ingredients that react to your body differently the others, so some cultures can eat healthy with alot of protein and you would be fit. But another culture can eat unhealthy with alot of calories that can make you chuby/ bigger than a person that is eating healthy. So those both can affect your fitness and dietary practices.
2. Food advertising is aimed to reach a wide range of people and age-levels through various sources and platforms. Advertisements can easily sway one's food choices, especially adolescents and younger children. Food companies spend a lot of time and money to convince people to buy their product.
hope this helps :)