the short answer
Nutrition coaching is a loop: set sensible calorie and macro targets for the individual, choose a tracking method the client will actually sustain (counting is optional, and wrong for some), give them structure to follow, then adjust from the weight trend and adherence over two-to-three-week blocks while coaching the behaviour underneath. The plan matters less than whether they follow it, so most of the skill is fit and adjustment, not the starting numbers. Protein first, a realistic deficit or surplus, and a method a client can keep up for months beats a perfect spreadsheet they quit in two weeks.