This is actually a question I often get and the person asking means one of 3 things to varying levels:
1) I don't trust or I question your sources;
2) I am uncomfortable with what your sources would recommend and/or
3) I have a trusting and personal relationship with my existing health care provider.
I don't have the answer to the overall question as to why your health care provider has not provided the same data and information, but I hope I can guide you through the process whereby you could arrive at an answer that most suits your needs and requirements.
Firstly, you are right to question all sources, in particular those you cannot verify in some way. You will find on this site a comprehensive, but by no means exhaustive, set of research links and books on which I have attempted to base all the assertions that I make regarding recovery from restrictive eating behaviors. I encourage you to review them and to take them to your health care professionals if you have more questions and want clarification.
Your health care practitioner may or may not have any specific education in the process of recovery and even if they are specifically offering services to support recovery, they may have been schooled in programs and processes that research has now proven are less effective than perhaps more recent approaches.
Tread carefully if you hope to educate your health care practitioner: some may be open to information provided by patients, others will not. On the other hand, do not remain with a practitioner that is not willing to partner with you in developing a recovery program that suits your needs and your understanding of your particular circumstance.
It is also true that your in-person professional health providers have the benefit of knowing your situation and circumstances in ways I cannot. They may be fully aware of all the relevant data and research but have decided to tread carefully with you to allow you to focus on your recovery in doable steps and stages. Just as all patients have distinct approaches, so too do health care providers. I know of many caring and highly skilled health care practitioners who prefer to maintain the role of "leader" in the care process because they have found it alleviates the patient's anxiety levels to do so.
Which brings me to the second reason behind asking me the above question: being uncomfortable with the actual recommendations within the research and information provided. If you sense that the information is correct, and you subsequently confirm it by doing your own research, then you can still be unwilling to accept it because it pushes too hard against all the reasons why you continue to apply eating behaviors that are self-harming.
It is alright to choose your own path and find health practitioners that can work with where you are at right now. These are complex, extremely complex, conditions and there is no one path to the end goal of replacing harmful eating behaviors with nurturing ones.
Finally, you may feel more of a personal relationship conflict when faced with data that you have confirmed is correct, want to embrace fully because you sense it is the path for you, and yet find your health care practitioner will not support the new direction at all.
Not wanting to "hurt" your health care provider is a common feeling. Wanting to trust them despite knowing their advice is not going to be right for you comes from an empathetic soul. You know that your health care provider has your best interests at heart and that s/he is well-trained and means to do the right thing. However, you have to come first.
In this case I encourage you to adopt a mindset that you might apply to health care providers taking care of a loved one: your child, parent or spouse (as examples). In those cases, you find it much less conflicting to apply a clear delineation that the health care provider is offering professional services. Should those services not suit the needs of your child or spouse, then you would be the first to seek second and third opinions.
Ask your own loved ones to support you in ensuring you do not continue to see any health care professional simply because you do not want to hurt his or her feelings.
The systemic aspects of metabolism, optimal weight set points, energy requirements, hunger and satiety are not understood fully by any of us, so it is more likely than not that your health care professional cannot provide you with all the data and information because no one has all the information yet.
If the information and data on this site is different than what you have received from your health care providers then that is likely because we are all the proverbial blind people describing the part of the elephant we happen to be touching. I hope the additional information serves you well in your pursuit of recovery working with the health care practitioners that are best at supporting your goals.