There's plenty of advice about nutrition out there.  The internet is a scary place.  But there are also sources that most people assume are trustworthy that you shouldn't be taking nutrition advice from either because, frankly, they aren't qualified. 

1. Doctors: I love and respect doctors.  I trust them with my own life and the lives of my clients.  Their medical expertise is invaluable. However, most people believe anything their doctor tells them about nutrition.  After all, they went to medical school, right?  You may be shocked to hear that 71% of medical schools fail to provide the required amount of nutrition education, and when they do it's in the form of biochemistry and falls way short of translating into dietary advice with real food.
2. Chiropractors: The self-proclaimed wellness gurus.  Their nutrition credentials are nonexistent.  Many sell supplements and weight loss products, which aren't even regulated by the FDA to begin with (no supplements are).  So, NO you don't need them to order a panel of labs to test for food allergies or vitamin deficiencies because they aren't qualified to treat these conditions.
3. Personal trainers: The least qualified of all on this list.  They received zero credible training in nutrition and mostly just give advice based on their personal opinion.  Yet, they freely give out dietary advice that's way beyond their scope of practice. 

So who can you trust?  Dietitians – the most qualified nutrition experts.  They receive 4 years of undergraduate training in nutrition, followed by an intense hand's-on internship where they learn to work in various settings including hospitals, doctor's offices, gyms, grocery stores, and so much more.  Upon completing their internship they sit for a registration exam to earn the RD credential (sort of like a doctor passing board exams).  They maintain their credential by participating in continuing education.  With an understanding of biochemistry, anatomy/physiology, food science, and psychology, RD's are well-equipped to help you navigate the confusing world of nutrition.