One of the biggest challenges to programming your diet for the first time is navigating between the twin obstacles of Dogma and Choice.
Turn left, and you’ll run into coaches and devotees of specific programs treat their nutrition plans as gospel; you’ll hear things like “gluten is a poison” or “our bodies didn’t evolve to eat fruit” or “there’s no reason to ever eat meat.” A healthy diet begins to sound a lot like prison: spare, confined, and punishing.
Turn right, and you will be overwhelmed by a cacophony of contradictory advice that makes it easy to feel like there is no true north. Given complete freedom, confirmation bias takes over. You start to pick out the articles that say bacon, chocolate, and wine are perfectly healthy, and decide you don’t need to make any serious changes (except maybe a couple extra glasses of wine).
As always, the best place to start is with the principles that affect weight gain and weight loss. Once you understand the principles, you can effectively program your own diet, free of dogma and unswayed by bad science and marketing gimmicks.
Eric Helms’s Nutrition Pyramid videos are a good start.