London Medical

About Karl

As well as providing expert endocrine care, Dr Neff is a sub-specialist in bariatric medicine and weight management. Within his NHS role he leads a multi-professional Medical Bariatric Clinic that provides pre-operative and post-operative care to people undergoing bariatric surgery. He has extensive experience in the use of non-surgical therapy in weight management, and is an advocate for people who are struggling with their weight.

Dr Neff ensures that both his assessment and therapeutic approaches are holistic, and so take account of all aspects of health. This allows us to devise a strategy that can offer the highest standard of evidence based assessment and treatment, while enabling us to consider all potentially effective treatment options.

Following graduation from the National University of Ireland in Galway, Dr Neff completed Higher Specialist Training in Endocrinology and Diabetes in Ireland, and wrote his PhD thesis on the effect of weight loss and bariatric surgery on the complications of diabetes in University College Dublin.

Dr Neff has published extensively on the effects of weight loss and bariatric surgery on metabolic disease. As a speaker at national and international conferences, he presents both his own research findings, and current bariatric and weight management topics. Within his academic role, he has contributed to international guidelines and to several textbooks on bariatric care.


Consultant Endocrinologist, King’s College Hospital NHS Foundation Trust.


Dr Neff speaks conversational French and Spanish.


My ambition is to provide holistic care to all of my patients, so that I can offer them the very best assessment and opinion on their symptoms and disease. Within the wider team, I strive to provide world class medical care by working collaboratively and contributing towards healthcare management so that all patients can receive the very best care possible.

I am very proud to have been a leader in the Medical School in University College Dublin, where I worked on the endocrine  programme, and restructured both the curriculum and assessment strategies. This was a significant accomplishment that had a lasting effect on my students.

My PhD and the work generated through this with my collaborations have been a constant source of academic interest and I have been very proud to continue to be able to work closely with some of the leading figures in bariatric care worldwide.

Within my current role, I am very proud to say that by working with my colleagues within the endocrine team, we are able to provide thorough assessments to our patients so that we can offer them a comprehensive endocrine evaluation. With my team, we continue to strive towards providing the very best endocrine care.


Here, under one roof, we offer patients a very wide range of expertise and treatments, provided by leading consultants in their specialist fields. More important still, our world-class experts are able to work as a single team, to develop a fully integrated treatment plan for each patient.