As a rough rule, it's about averages. Rich people with lots of resources will be taller and reach a plateau within their society, compared to poorer people with fewer resources. But there are always exceptions in each group.

Diseases or childhood illness may prevents you obtaining maximum height.

Nutrition is more than just calories. Ideally you have a varied diet. For instance, you could be really obese from eating sugar but your diet is lacking in protein or a particular vitamin.

The final thing is we can't rule out any effects from your grandparents epigentics, or other random things we cannot predict. Some medications will affect future children.