Say that your car has broken down.
You go ask your friends for recommendations of a good mechanic. You don’t ask for recommendations on how to fix it yourself with zero automotive knowledge, and then do your best to follow the instructions on what “worked for them”.
Health and fitness are weird. You can do the wrong thing enough. And if we only focus on a few metrics, like weight loss or muscle gain, you will look like what you are doing is “right” and “works”. However, you can gain muscle and lose fat while having serious nutritional deficiencies, or while creating long-term injuries that will only really show up in later life.
When our car breaks down, we seek a professional, particularly when we lack knowledge of the subject.
When we want advice on fitness and nutrition, we crowdsource it from our friends based on what “works for them”. This is a backward approach.
Every time I see a friend post about weight loss on facebook I see people recommending dangerous, stupid, and unscientific solutions. Many of which contain highly toxic ways of thinking about food. When confronted about their statements they will often claim it “works for them." Then, when questioned what they mean by that they are unable to answer.
Social support is incredibly important. It's okay to get friends to recommend classes with professional trainers, science-based books by nutritionists, and other resources that do not rely on “it works for me” as their source.
However, refuse to take advice from people that do not know what they are talking about, and don’t ask them.
You wouldn’t try to fix your car based off of a comment thread on the internet with no knowledge of auto-repair, for the same reason you shouldn’t trust your health to the advice of strangers without first seeking a professional (and your friends can help you do this!). Ask for resources, not advice. Ask for support, not direction.