Ann Louise Gittleman (born June 27, 1949) is an American author and proponent of alternative medicine, especially fad diets.

[6] In 1994, she was featured in an advertising campaign for Rejuvex,[7] a dietary supplement for menopause symptoms that is not supported by scientific or clinical evidence.

[13] Gittleman's books have been criticized as inconsistent with the best understanding of health and nutrition,[2] and for presenting scientific research in a simplistic and one-sided manner.

[3][5] Gittleman's suggestion to detoxify as part of the Fat Flush Plan has made her diet the subject of criticism from some nutritionists and medical doctors.

[14] Dr. Judith Stern, vice president of the American Obesity Society, has called the Fat Flush Plan "pseudoscience" that promises everything, but is "a fantasy".