Holy smokes!! I'd fire that doctor in a minute. IMO that's terrible thing to say to a patient. I weigh in once a week, although sometimes I weigh twice a week. Water weight, sodium intake, dehydration, and other things can make the scale fluctuate. I also know that I tend to really carry those numbers in my head that are on the scale and I want a "bigger picture" focus on my overall health, emotional health, and of course with loosing weight- not be as worked up over the numbers on the scale.
The weight loss will happen and I'll record it, but I like to also keep a running average of weight loss going so I can see the bigger picture.
Once I get to transition and maintenance then maybe just once a week or twice.