Clauses of time and
condition vs
object clauses
The future possible (real) situation.

If I eat too much fast food, I will get fat.
Such type of a sentence
is used to talk about a result [I’ll get fat] that
is likely to happen or is almost certain to
happen in the future IF the condition in the if
clause [if I eat too much] happens.
Состав предложений с
придаточным времени или
условия
Придаточная часть
(гипотеза)
Главная часть
(результат)
If/when + Present Simple
will + V
If it doesn't rain tomorrow, we will go to the river.
When Katya comes, we’ll have dinner.