How can I get my hair back naturally? Is there a routine I should follow or foods I should eat to help? (Photo)

You can't get back the hairs you lost, like you can't get back your youth.  Genetic hair loss is permanent.  Juvenile hair loss is also permanent.  If you want to understand what you have, you need to see a doctor for an examination.

It is important to understand that there is likely 2 things going on :Genetic hair loss - also called androgenetic alopeciaNormal reshaping of your childhood hairline (a phenomenon called hairline maturation)Hairline maturation is a "normal" process that most men experience and there is no treatment to alter this normal process. As far as genetic hair loss goes, there are a few options to consider. You might want to make an appointment with a specialist to confirm the diagnosis and discuss all of the following treatments in great detail. Topical Minoxidil lotion or foam helps a very slight amount in the front (research in 2013 confirmed this) and other treatments include LLLT laser therapy and platelet rich plasma (PRP) therapy. Hair transplantation is not an option at 18. There are no foods or dietary changes that will affect your hair loss patterns. 

Your biggest enemy is the
progressive thinning leading to a balding pattern that is not evident at this
point in time. The degree of thinning that you are showing would suggest that
you should see a doctor who most likely will get Bulk Measurements of your hair
to determine the degree of the thinning that you are presently having. If the
diagnosis is early genetic hair loss, then the best treatment would be the drug
finasteride which is highly effective in men of your age and may not only stop
the hair loss but possibly reverse it. If you are developing a more advanced
balding pattern the best test to get will determine the Bulk Measurements of
your hair and this will show, over a one-year time frame, how effective the
treatment will be. Once you know this information, then you and your doctor
need to develop a MASTER PLAN which will define what you need to do over the
years to come.