The dudes have regularly quoted 1-1.5g/kg/day (kg of lean body mass) as a rough guideline, but have also cited a number of experiment on nitrogen balance where some folks are good down to as low as 0.3g/kg/d.
I have had a number of friends and acquaintances over the years that were involved in body building/weight training. Many of these people some how got the message that they have to eat lots and lots to grow muscle because that is what all the pro athletes do. Then because it is easier to eat than lift weights they drink a protein shake and skip the hard part of the workout… Marketing may play a role in this.
I have done some weight lifting as well, and on/around weight training days, I will crave MEAT. Other days not so much. Most of us have a pretty good feedback mechanism to know how much protien we need. This doesn’t tie into sugar/fat. Just plan to get a fair amount each day.
Just like other calculators mathematical models and guidelines these numbers are +/- one standard deviation from an average of a population. That population was probably lean male college students (or lab animals) because they are plentiful and easy to study. These numbers can’t take into account all the possible environmental factors that make you you.
If your only eating 30g of protein a day, this statement might clue you in that you might need to eat a little more. Just be cause it is in print doesn’t make it right (for you).