Is a ketogenic diet safe for your heart?

Dr. Stephen Phinney and the Virta Team

In the context of a well-formulated ketogenic diet (high fat, low carb, moderate protein), the intake of fat is not only safe, but imperative for long-term success. There have been multiple studies of low carbohydrate and ketogenic diets lasting up to three years, with no increase in cardiac events or mortality (Halton, 2006). Furthermore, cardiac risk factors improve, with lowering of triglycerides, improved blood pressure, improved glycemic control, and increased HDL (Dashti, 2004; Hu, 2014; Nordmann, 2006; Feinman, 2015; Mirza, 2009). Interestingly, the largest trial ever done on low fat diets, the Women’s Health Initiative, showed no decrease in heart disease events or mortality (Howard, 2006). Controlled studies have consistently failed to show a clinical association between high saturated fat intake and adverse cardiovascular outcomes (Siri-Tarino, 2010).

The science on cholesterol and saturated fat has evolved greatly in the past few decades. It is now accepted that dietary cholesterol does not raise blood cholesterol, and this has even been recognized in the new dietary guidelines. Multiple large meta-analyses have shown no association between saturated fat intake and cardiovascular events or increased mortality. Both prior studies and our research have shown that paradoxically, in the setting of a ketogenic diet, higher dietary intake of saturated fat actually decreases serum saturated fat (Forsythe, 2008). This is hypothesized to be due to preferential use of dietary saturated fat as fuel in the keto-adapted state.

You can read more on saturated fat here: The Sad Saga of Saturated Fat


Feinman RD, Pogozelski WK, Astrup A, Bernstein RK, Fine EJ, Westman EC, Accurso A, Frassetto L, Gower BA, McFarlane SI, Nielsen JV, Krarup T, Saslow L, Roth KS, Vernon MC, Volek JS, Wilshire GB, Dahlqvist A, Sundberg R, Childers A, Morrison K, Manninen AH, Dashti HM, Wood RJ, Wortman J, Worm N. Dietary carbohydrate restriction as the first approach in diabetes management: critical review and evidence base. Nutrition. 2015 Jan;31(1):1-13. doi:10.1016/j.nut.2014.06.011. Epub 2014 Jul 16. Review. PubMed PMID: 25287761.

Dashti HM, Mathew TC, Hussein T, Asfar SK, Behbahani A, Khoursheed MA, Al-Sayer HM, Bo-Abbas YY, Al-Zaid NS. Long-term effects of a ketogenic diet in obese patients. Exp Clin Cardiol. 2004 Fall;9(3):200-5. PubMed PMID: 19641727; PubMed Central PMCID: PMC2716748.

Halton TL, Willett WC, Liu S, Manson JE, Albert CM, Rexrode K, Hu FB. Low-carbohydrate-diet score and the risk of coronary heart disease in women. N Engl J Med. 2006 Nov 9;355(19):1991-2002. PubMed PMID: 17093250.

Hu T, Bazzano LA. The low-carbohydrate diet and cardiovascular risk factors: evidence from epidemiologic studies. Nutr Metab Cardiovasc Dis. 2014 Apr;24(4):337-43. doi: 10.1016/j.numecd.2013.12.008. Epub 2014 Jan 2. Review.PubMed PMID: 24613757; PubMed Central PMCID: PMC4351995.

Mirza N, Marson AG, Pirmohamed M. Effect of topiramate on acid-base balance: extent, mechanism and effects. Br J Clin Pharmacol. 2009 Nov;68(5):655-61. doi: 10.1111/j.1365-2125.2009.03521.x. PubMed PMID: 19916989; PubMed Central PMCID: PMC2791971.

Nordmann AJ, Nordmann A, Briel M, Keller U, Yancy WS Jr, Brehm BJ, Bucher HC. Effects of low-carbohydrate vs low-fat diets on weight loss and cardiovascular risk factors: a meta-analysis of randomized controlled trials. Arch Intern Med. 2006 Feb 13;166(3):285-93. Review. Erratum in: Arch Intern Med. 2006 Apr 24;166(8):932. PubMed PMID: 16476868.

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