You're advising too much protein: One to one and a half grams per kilogram is enough for almost anyone except the most devout lifters (read: those who compete).
As for determining calories, most people eat a similar amount every week, so all they need to do is track their calories for a week then subtract from there until they're losing one to two pounds per week; not counting the first one or two weeks where they'll lose a lot of water weight.
1 gram per pound of body-weight is a good amount for someone who lifts weights (not only those who compete) and is not hard to achieve every day. Would you rather they overload on carbs all day? It's even more important if you're trying to lose weight: cutting too many calories and not getting enough protein will most likely result in you losing a lot of muscle mass.
