The Surprising Ways Your Friends Affect Your Life
Brad Barket/Getty Images Entertainment/Getty Images

One of the most important decisions you can make for your social life, your love life, and even your health is who you become friends with. Why? Because there are so many ways your friends influence you without you even realizing it. So, by being smart about who you befriend, you're also being smart about your other lifestyle choices.

We may not actually be clear on who our friends are, though. A study published in PLOS ONE last year found that only about half of the people we consider our friends consider us their friends as well. This matters, because friends who also consider us their friends are more likely to influence us. Someone who shares lots of mutual friends with you and doesn't have more friends than you is more likely to consider you a friend — and therefore more likely to influence you.

When I was little, all that seemed to matter in a friendship was whether or not the other person and I liked to do the same things. Then, after experiencing my first betrayal at the hands of a friend, I realized that finding someone kind and trustworthy was important to avoid those situations. Now that I'm older and have less time on my hands, I'm even pickier about who I'm friends with. They have to be someone I admire, not just someone who's convenient.

And data backs me up: who we befriend is a big decision that shouldn't be taken lightly. Here are just a few ways our friends can influence us.

1Friends Influence How Long Our Relationships Last

GIPHY

A 2015 study in the Journal of Family Psychology found that the less approving friends were of same-sex and interracial relationships, the more likely those relationships were to end. So, if you're in a relationship that society stigmatizes, it's extra important to have supportive friends.

2Your Friends In Your 30s Affect Your Health In Your 50s

GIPHY

A 2015 University of Rochester study found that the closer people were with their friends in their 30s, the better their physical and mental health was in their 50s. So, don't feel pressure to waste time on superficial interactions. It could hurt your health later.

3Friend Drama Can Hurt Your Heart

GIPHY

The more fights and conflicts people have with their friends, the more likely they are to suffer from high blood pressure, according to a study in Health Psychology. Plus, older adults with fewer close friendships have weaker hearts, another Health Psychology study found. So, if your friends aren't loyal, they could almost literally break your heart.

4Your Friends Influence Your Eating Habits

GIPHY

We tend to eat what the people around us are eating, according to a meta-analysis published in Social Influence. So, if we consistently surround ourselves with health-conscious people, we're more likely to be health-conscious ourselves. And spending time around people who diet or engage in other disordered eating behaviors can be detrimental.

5Friends Influence Your Sexual Choices

GIPHY

A National Campaign To Prevent Teen And Unplanned Pregnancy analysis found that friends were the second-biggest influence on teens' sexual decisions, right after parents, and the biggest influence among people ages 20 to 24. It's awesome that people feel like they can turn to their friends for sex advice, though it's also important to remember these decisions are deeply personal.

The moral of the story? Make friends with people who eat the way you want to eat, share your views on sex, and judge your relationships based on what's really important. But most of all, form friendships that include trust and respect, because it'll improve your health way down the line.