Both are possible, it depends on the situation. If I am hungry, I go to buy food - this is something that is generally true and happens regularly. If I am hungry, I will go and buy food. - This is describing a single possible event in the future.

You can use "if I am hungry, I go to buy food" to describe what you do usually. The phrase "if I am hungry, I will go to buy food" can be used to describe your possible future plans.

1. If i am hungry, I go to buy food. (this form is called the ZERO conditional) 2. If I am hungry, I will go to buy food. (this form is called the FIRST conditional) #1 is technically more correct, but #2 is what most English speakers say. Go with #2. Tips to improve the readability of your English writing: 1. Always capitalize the pronoun "I", always. 2. Always capitalize the first word of every sentence. If you don't do #1/#2, then I assume you are either lazy or on Day 1 of your English studies. You don't want me to assume either of these, do you?

It helps to re-word the phrase. If you are saying what you will do in the future if a condition is met, you say: I will go to buy food if I am hungry. I will buy a ticket to La Traviata if I can find the money. I will take the subway if my car breaks down. I will go to Paris if the airfare is under $600. I will join you at the show if I can find a babysitter. If you are talking about something you do habitually, sometimes you have a choice between "if" and "when" and sometimes it's much clearer to use "when" and especially "whenever": I go to the grocery store if/when I am hungry. I go to Paris whenever I have the money. I take the subway if/when my car breaks down. I go to the opera whenever I have the money.