Steven Robert Gundry is an American physician, low-carbohydrate diet author, and former cardiothoracic surgeon. He is known for promoting the controversial lectin-free diet, which he claims can prevent and reverse modern diseases. Gundry runs an experimental clinic investigating the impact of this diet on health and sells supplements that he claims protect against the effects of lectins. His claims about lectins have been classified as pseudoscience by scientists and dietitians.