Everybody has something to say about nutrition or "diet". There tends to be a cough cough grain of truth to most of the popular "fad" diets. Eventually everything boils down to macro (protein, carbs, fat) and micro nutrition (vitamins, minerals, etc.). Most foods are some combination of the 3 macros so everything comes down to 3 things based on your goals: getting a decent ratio across the 3 macros for whatever change or maintenance you're targeting, getting the right quantity & frequency to absorb what you need, and getting enough whole foods and micronutrients to sustain organ function so you can use those gains in the first place.
Trying to put on muscle? Might need to increase your protein. Trying to lose weight? Might need to limit carbs. Are you a young skinny guy wanting to get stronger? Just eat. Eat a lot. Much of what's easily available to us in America has an excess of carbs (particularly sugar or pseudo-sugar) and fats. Learn the basic mechanics of your anatomy (as well as what your stomach can tolerate) and take ownership of your nutrition.