Ian Marber became involved in nutrition after suffering with undiagnosed food allergies sensitivities during his twenties. His condition was later identified as coeliac disease, a life-long intolerance to gluten. He left a successful career in property investment to return to college to study nutrition at the Institute of Optimum Nutrition, and, on graduation, Ian joined a busy practice in Harley Street. This allowed him to gain valuable experience in many areas of nutrition before leaving Harley Street to work in his own private practice in Chelsea, London. Ian's work includes preventative nutrition such as cardiovascular health and children’s nutrition and, in particular, food allergies, eating disorders and digestive problems, subjects on which he frequently writes. Ian is currently studying for a Masters degree at Middlesex University.

Ian favours working closely with his clients to identify the correct nutrition for them, as individuals. Although he does use nutrient supplementation where appropriate, Ian will always favour eating the right foods over using supplements. In addition to spending his days working with clients on a one-to-one basis, he runs many workshops and is often invited to talk to groups about specific areas of nutrition.

Ian Marber has regularly appeared on Richard & Judy as their expert nutritionalist. A columnist for several publications, Ian writes on a regular basis for many of Britain's leading magazines and newspapers. He is a regular contributor to Healthy, Top Sante, Harpers Bazaar and Zest, as well as Marie Claire, Red, Eve, Metro and Attitude.

Ian has had much success as an author with his Food Doctor books, The Food Doctor Diet published by DK in 2004 was a bestseller, followed by The Food Doctor Everyday Diet which shows you how to carry on maintaining new eating habits for life, with the 10 simple Food Doctor healthy eating principles. The Food Doctor Diet Club uses ten real-life motivational case studies to prove the diet works and his latest title, The Food Doctor Ultimate Diet, provides the comprehensive guide to changing the way you eat forever.