The obesity epidemic requires a paradigm shift. Several medical myths stand in the way of taking the most effective steps to safely help patients lose weight. The most important myth relates to saturated fat. Saturated fat consumption does not contribute to cardiovascular disease. This must be understood and accepted by the medical community so that sound advice can be given.
A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD.( Am J Clin Nutr. 2010 Mar;91(3):497-9. )
In fact, as early as 2004, Mozaffarian et. al. investigated the influence of diet on atherosclerotic progression in postmenopausal women with quantitative angiography and found that:
In multivariate analyses, a higher saturated fat intake was associated with a smaller decline in mean minimal coronary diameter (P = 0.001) and less progression of coronary stenosis (P = 0.002) during follow-up. (Am J Clin Nutr. 2004 Nov;80(5):1175-84)
In addition, they further found that:
Carbohydrate intake was positively associated with atherosclerotic progression (P = 0.001), particularly when the glycemic index was high.
Polyunsaturated fat intake was positively associated with progression when replacing other fats (P = 0.04)
These findings should come as no surprise given the basic science of atherosclerosis. Oxidized and glycated LDL stimulate macrophages to become foam cells initiating the creation of plaque. Cellular receptors that allow macrophages to ingest oxidized LDL are specific for oxidized LDL. These receptors do not recognize normal LDL to a significant degree.
Holovet et. al. studied the ability of oxidized LDL versus the Global Risk Factor Assessment Score (GRAS) to detect coronary artery disease. GRAS identified coronary artery disease 49% of the time, while oxidized LDL was correct 82% of the time.
In a large prospective study, Meisinger et al found that plasma oxidized LDL was the strongest predictor of CHD events when compared to conventional lipoprotein risk assessment and other risk factors for CHD.
Polyunsaturated fats are easily oxidized, saturated fats are not. It is the polyunsaturated fatty acids (PUFA) in the membrane of LDL particles that become oxidized and then initiate the cascade of inflammatory events leading to atherosclerosis. The major source of these PUFA in the American diet are “vegetable oils” (corn oil, soy oil etc.) rich in the omega-6 PUFA, linoleic acid.
So why is this important to understand relative to the obesity epidemic? Because the most effective weight loss “diet” is arguably a low carbohydrate/high fat (LCHF) diet. This approach does not require calorie counting. This approach has been demonstrated to spontaneously reduce caloric intake whereas low fat diets require calorie counting and result in persistent hunger.
When compared to low fat calorie restricted diets the LCHF approach has been equal or superior with respect to weight loss, insulin sensitivity, blood pressure reduction, and lipid profiles whenever these parameters have been measured.
But LCHF has not been embraced by the medical community due to the perceived dangers of saturated fat consumption and a low-fat ideology that lacks legitimate scientific evidence.
Once we dispel the mythology of saturated fat, the safety and efficacy of LCHF will be more readily accepted by physicians, the media and the lay public.
The nutritional villains in our society are highly refined and easily oxidized “vegetable oils” filled with pro-inflammatory omega-6 PUFA (linoleic acid), added sugar (especially HFCS) so prevalent in most processed foods and soft drinks, and the nutrient poor wasted calories of processed flour foods. These three culprits are responsible for our epidemics of obesity, insulin resistance and metabolic syndrome. These three conspire together to generate fatty liver disease, atherosclerotic plaque, and chronic inflammation.
When a LCHF approach is combined with eating only fresh whole foods and avoiding added sugar, refined flour, and unhealthy “vegetable oils”, we have the perfect recipe for our obesity epidemic.
The following references provide examples of studies that have demonstrated the efficacy, safety and usual superiority of the LCHF approach to weight loss.
- The A to Z Weight Loss Study: A Randomized Trial, JAMA March 7, 2007, .
- Effects of a low-intensity intervention that prescribed a low-carbohydrate vs. a low-fat diet in obese, diabetic participants. Obesity (Silver Spring). 2010 Sep;18(9):1733-8.)
- On July 17, 2008, the New England Journal of Medicine published an article describing a two-year study of men and women in Israel. The study showed that, compared with the low-fat diet, the low-carbohydrate diet produced greater weight loss and had more favorable effects on lipids.
- August 3, 2010, the Annals of Internal Medicine published an article describing a two-year low-carb low-fat study of men and women in the United States. The authors concluded that, “Successful weight loss can be achieved with either a low-fat or low-carbohydrate diet when coupled with behavioral treatment. A low-carbohydrate diet is associated with favorable changes in cardiovascular disease risk factors at 2 years.”
- Obesity (Silver Spring). 2007 Jan;15(1):182-7.The effects of a low-carbohydrate ketogenic diet and a low-fat diet on mood, hunger, and other self-reported symptoms. McClernon FJ, Yancy WS Jr, Eberstein JA, Atkins RC, Westman EC.
- Exp Clin Cardiol. 2004 Fall;9(3):200-5.Long-term effects of a ketogenic diet in obese patients.Dashti HM, Mathew TC, Hussein T, Asfar SK, Behbahani A, Khoursheed MA, Al-Sayer HM, Bo-Abbas YY, Al-Zaid NS.
- Acta Cardiol. 2007 Aug;62(4):381-9.Low carbohydrate ketogenic diet enhances cardiac tolerance to global ischaemia. Al-Zaid NS, Dashti HM, Mathew TC, Juggi JS.
- Exp Clin Cardiol. 2004 Fall;9(3):200-5.Long-term effects of a ketogenic diet in obese patients. Dashti HM, Mathew TC, Hussein T, Asfar SK, Behbahani A, Khoursheed MA, Al-Sayer HM, Bo-Abbas YY, Al-Zaid NS.
- Int J Cardiol. 2006 Jun 16;110(2):212-6. Epub 2005 Nov 16. Effect of a low-carbohydrate, ketogenic diet program compared to a low-fat diet on fasting lipoprotein subclasses. Westman EC, Yancy WS Jr, Olsen MK, Dudley T, Guyton JR.
- 2009 Nov-Dec;25(11-12):1177-85.Therapeutic role of low-carbohydrate ketogenic diet in diabetes. Al-Khalifa A, Mathew TC, Al-Zaid NS, Mathew E, Dashti HM.
- Mol Cell Biochem. 2007 Aug;302(1-2):249-56. Epub 2007 Apr 20. Beneficial effects of ketogenic diet in obese diabetic subjects.Dashti HM, Mathew TC, Khadada M, Al-Mousawi M, Talib H, Asfar SK, Behbahani AI, Al-Zaid NS.
- Mol Cell Biochem. 2006 Jun;286(1-2):1-9. Epub 2006 Apr 21.Long term effects of ketogenic diet in obese subjects with high cholesterol level. Dashti HM, Al-Zaid NS, Mathew TC, Al-Mousawi M, Talib H, Asfar SK, Behbahani AI.
- Nutr Metab (Lond). 2004 Nov 8;1(1):13. Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women. Volek J, Sharman M, Gómez A, Judelson D, Rubin M, Watson G, Sokmen B, Silvestre R, French D, Kraemer W.
- Ann Intern Med. 2004 May 18;140(10):769-77. A low-carbohydrate, ketogenic diet versus a low-fat diet to treat obesity and hyperlipidemia: a randomized, controlled trial. Yancy WS Jr, Olsen MK, Guyton JR, Bakst RP, Westman EC.
- Nutr J. 2011 Oct 12;10:112. Effect of ketogenic Mediterranean diet with phytoextracts and low carbohydrates/high-protein meals on weight, cardiovascular risk factors, body composition and diet compliance in Italian council employees. Paoli A, Cenci L, Grimaldi KA.
- Arch Intern Med. 2010 Jan 25;170(2):136-45. A randomized trial of a low-carbohydrate diet vs orlistat plus a low-fat diet for weight loss. Yancy WS Jr, Westman EC, McDuffie JR, Grambow SC, Jeffreys AS, Bolton J, Chalecki A, Oddone EZ.
- Nutr Metab (Lond). 2008 Dec 19;5:36. The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus. Westman EC, Yancy WS Jr, Mavropoulos JC, Marquart M, McDuffie JR.
- Nutr J. 2008 Oct 26;7:30. Spanish Ketogenic Mediterranean Diet: a healthy cardiovascular diet for weight loss. Pérez-Guisado J, Muñoz-Serrano A, Alonso-Moraga A.
- Vopr Pitan. 2007;76(3):29-34. Efficacy of low-carbohydrate diet in the treatment of obesity in adolescents]. [Article in Russian] Sorvacheva TN, Peterkova VA, Titova LN, Vitebskaia AV, Pyr’eva EA.
Dig Dis Sci. 2007 Feb;52(2):589-93. Epub 2007 Jan 12. The effect of a low-carbohydrate, ketogenic diet on nonalcoholic fatty liver disease: a pilot study. Tendler D, Lin S, Yancy WS Jr, Mavropoulos J, Sylvestre P, Rockey DC Westman EC.