Setting your own calorie or macro goals

I let the program do it because it knew more than I did. 😉

I used MFP, tweaked the protein up a little when I realized it was helping me stay fuller.

I started with theirs and tweaked. I needed more calories than I was getting and realized that I find carbs and protein more filling, so I upped them and lowered fat some.

I started with MFP default goals and over the years have tweaked them, in my head at least, as I've gained knowledge and experience. I don't really need the numbers in the app to reflect my actual goals, which are far more flexible and generally ranges rather than specific points.

Tweaked. I found that MFP seriously under-estimated my calorie needs (which is unusual, but it happens). Once I realized, I increased my calorie level to one that was sensible, based on several weeks of personal weight-loss results.

I also came to think of my macro goals in terms of grams rather than percents. I think the MFP defaults are a good starting point for most people, but they can be adjusted to help with satiation, or better meet personal nutritional goals. I set my percents so that at base calories it would approximate my gram goals, but I eat to the gram goals, not the percents. (If this makes my daily totals a mix of red and green on MFP, I just pretend it's Christmas ).

It's important to realize that you don't need to be exact in meeting the macro goals. Close is good enough, especially if you're a little over on something one day, under the next, so that averages out pretty close to your goals over time. IMO, the only things that require adjustment are the really big and persistent discrepancies, and only if they cause you an energy or health problem, or when they involve being under persistently on protein or fats.

Personally, I also target getting 5+, ideally 10+, daily servings of varied, colorful veggies and fruits for micronutrients and fiber, and work on getting much of my fats from monounsaturated or polyunsaturated sources (things like nuts, seeds, olive oil, avocados, etc.). I think it's useful to think of nutritional goals as something to assess, then work on gradually accomplishing over time, by remodeling one's routine way of eating in a manageable, enjoyable way. It's not something that needs to be an instantaneous stressful revolution. (Humans are adaptable omnivores; serious problems from deficiencies normally take a long time to develop. We have time to make fixes.)

These are some sources that I found helpful in thinking about my personal goals (YMMV):

https://community.myfitnesspal.com/en/discussion/819055/setting-your-calorie-and-macro-targets/p1
https://examine.com/nutrition/how-much-protein-do-you-need/
https://fnic.nal.usda.gov/fnic/dri-calculator/

(I personally like to get more protein than that last one recommends.)