Nutrition science has a lot of noise in it. Here's the small set of things that are actually well-supported, organized for exactly how you train.
These apply to everyone, regardless of your specific training style.
Prioritize a quality protein source at every meal; it's the most reliable single lever for both body composition and staying full.
Don't wait until you're thirsty during training; use the Water Intake Calculator for a daily target.
Build meals around fruit, vegetables, whole grains, and lean protein; you don't need to eliminate processed food, just make it the minority.
A solid plan followed 80-90% of the time outperforms a perfect plan abandoned after two weeks.
Use the Calorie & Macro Calculator for a starting point, then adjust based on real progress.
Select your training style for specific macronutrient targets.
General educational information, not personalized dietary or medical advice. Anyone with a specific health condition should consult a registered dietitian or physician.