According to the USDA, a low-fat diet – as the name implies – is a diet that consists of little fat, especially saturated fat and cholesterol, which are thought to lead to increased blood cholesterol levels and heart attack. It is important to know that dietary fat is needed for good health, as fats supply energy and fatty acids, in addition to supplying fat-soluble vitamins like A, D, E, and K.
In recent years the exact health benefits of a low-fat diet have been debated. A 2006 study published by the Journal of the American Medical Association concludes that a low-fat diet did not result in weight gain and did not reduce risk of colorectal or breast cancer among postmenopausal women. However, this study was criticized by several epidemiologists for its lack of validity (see "Criticisms" in the Women's Health Initiative article). Recently, the Nurses' Health Study from the Harvard School of Public Health reported from a Dietary Approaches to Stop Hypertension (DASH), and found that a diet "with high intake of fruits, vegetables, and whole grains, moderate intake of legumes, nuts, and low-fat dairy products, and low intake of red and processed meats and sodium, was significantly associated with lower risk of coronary heart disease and stroke in women." A 2002 Cochrane Review found low-fat diets to be no more effective than other weight loss diets in achieving lasting weight loss, two newer studies concluding the same, published 2008.
Plant-based diets 
Doctors Dean Ornish, T. Colin Campbell, John A. McDougall, Caldwell Esselstyn and Neal D. Barnard claim that high animal fat and protein diets, such as the standard American diet, are detrimental to health. They also state that a lifestyle change incorporating a low-fat vegan diet could not only prevent various degenerative diseases, such as coronary artery disease, but reverse them.
- "MyPyramid". USDA. Retrieved April 23, 2011.
- USDA, Choose a diet low in fat, saturated fat, and cholesterol, Retrieved on July 2007
- Low-Fat Dietary Pattern and Weight Change Over 7 Years
- Low-Fat Dietary Pattern and Risk of Invasive Breast Cancer
- Low-Fat Dietary Pattern and Risk of Colorectal Cancer
- Adherence to a DASH-Style Diet and Risk of Coronary Heart Disease and Stroke in Women
- Pirozzo S, Summerbell C, Cameron C, Glasziou P. Advice on low-fat diets for obesity. Cochrane Database of Systematic Reviews 2002, Issue 2. Art. No.: CD003640. doi:10.1002/14651858.CD003640
- Hession M, Rolland C, Kulkarni U, Wise A, Broom J (August 2008). "Systematic review of randomized controlled trials of low-carbohydrate vs. low-fat/low-calorie diets in the management of obesity and its comorbidities". Obes Rev 10 (1): 36–50. doi:10.1111/j.1467-789X.2008.00518.x. PMID 18700873. "There was a higher attrition rate in the low-fat compared with the low-carbohydrate groups suggesting a patient preference for a low-carbohydrate/high-protein approach as opposed to the Public Health preference of a low-fat/high-carbohydrate diet. Evidence from this systematic review demonstrates that low-carbohydrate/high-protein diets are more effective at 6 months and are as effective, if not more, as low-fat diets in reducing weight and cardiovascular disease risk up to 1 year."
- Shai, I. et. al. (2008-07-17). "Weight Loss with a Low-Carbohydrate, Mediterranean, or Low-Fat Diet". New England Journal of Medicine 359 (3): 229–241. doi:10.1056/NEJMoa0708681. PMID 18635428. Retrieved 2011-02-28. "Conclusions: Mediterranean and low-carbohydrate diets may be effective alternatives to low-fat diets."
- Segelken, Roger (2001-06-28). "China Study II: Switch to Western diet may bring Western-type diseases". Cornell Chronicle. Retrieved 2006-09-15.
- "China-Cornell-Oxford Project On Nutrition, Environment and Health at Cornell University". Division of Nutritional Sciences. Cornell University. Retrieved 2006-09-15.
- Barnard, Neal D. (2007). Dr. Neal Barnard's Program for Reversing Diabetes. New York: Rodale. pp. 40–50. "Set aside animal products"
- Ornish D, Brown SE, Scherwitz LW, et al. (July 1990). "Can lifestyle changes reverse coronary heart disease? The Lifestyle Heart Trial". Lancet 336 (8708): 129–33. doi:10.1016/0140-6736(90)91656-U. PMID 1973470.
- Campbell TC, et al. (Oct 2002). "Medically supervised water-only fasting in the treatment of borderline hypertension". J Altern Complement Med. 8 (5): 643–50. doi:10.1089/107555302320825165. PMID 12470446.
- McDougall J, et al. (Feb 2002). "Effects of a very low-fat, vegan diet in subjects with rheumatoid arthritis". J Altern Complement Med. 8 (1): 71–5. doi:10.1089/107555302753507195. PMID 11890437.
- Esselstyn CB Jr. (Aug 1999). "Updating a 12-year experience with arrest and reversal therapy for coronary heart disease (an overdue requiem for palliative cardiology)". Am J Cardiol. 84 (3): 339–41. doi:10.1016/S0002-9149(99)00290-8. PMID 10496449.
- Barnard ND, et al. (Aug 2006). "A low-fat vegan diet improves glycemic control and cardiovascular risk factors in a randomized clinical trial in individuals with type 2 diabetes". Diabetes Care 29 (8): 1777–83. doi:10.2337/dc06-0606. PMID 16873779.