He is a founder member of Delhi Diabetic Forum (DDF) and has been office bearer of DDF in various capacities. He is also a member of the executive board of Diabetes India, a prestigious nationwide organization with best of the diabetes specialists in country working for the cause of diabetes in India. He is a member of the Research Society for the Study of Diabetes in India (RSSDI), and has served the RSSDI in various capacities including his tenure as honorary secretary of RSSDI 2017-2019. He is a Past President of RSSDI Delhi Chapter and has been a member of RSSDI National Executive Committee since 2010.

Dr. Makkar is a member by invitation to American Diabetes Association, a member of European Association for Study of Diabetes(EASD), European Association for Study of Obesity(EASO), and Canadian obesity research network. He is also a trainer for Staged Diabetes Management Program certified from International Diabetes Centre, Minneapolis. He is also a Fellow of Royal College of Physicians(Glasgow and Edinburgh), American College of Physicians, and American College of Clinical Endocrinology.

Dr. Makkar is widely traveled nationally as well as internationally and has been a guest faculty to numerous national & international conferences. He has authored many chapters relating to Obesity and Type 2 Diabetes and has a number of national and international publications to his credit. Dr. Makkar is also involved in clinical research in the field of diabetes, obesity & metabolic syndrome.

Dr. Makkar enjoys the qualities of an astute clinician with ever-growing quest for knowledge and its intelligent application for the treatment of patients. At the same time he provides that personal healing touch which all the patients appreciate right from the time of first interaction.

Despite his busy schedule, Dr. Makkar still takes out to do charity for the poor patients by offering free/subsidized care to many patients in his clinic and in the community.