Training of the new techniques for obesity surgery was funded by grants from the Wolfson Foundation and the Leeds Teaching Hospitals NHS Trust.
Subsequently, much of the training techniques developed were incorporated into the Core Skills Course in Laparoscopic Surgery, run by the Royal College of Surgeons of England.
McMahon was also involved in the design of the Nuffield Hospital in Leeds, so that it could become a centre of excellence for all types of laparoscopic surgery, especially the surgical treatment of obesity.
He is the founder member of the society of Minimally Invasive General Surgeons, and was Chairman of the Education Committee of the European Association of Endoscopic Surgery.
McMahon was the first surgeon in the UK to perform laparoscopic (minimally invasive) gastric bypass, duodenal switch, and sleeve gastrectomy.