If you follow or seek health advice, it would be hard to miss the wave of recommendations to lower “carbohydrates” to minimal levels and focus on meals higher in fat and protein to promote the use of ketone bodies as fuel. There are dozens of books and websites dedicated to this trend, some backed by prominent figures with medical degrees. In March of this year, a start-up called Virta Health was launched to provide online coaching to follow this dietary pattern to reverse type 2 diabetes (DM2).
I was discussing health coaching this week with an expert in functional medicine and the science of whole food plant based diets, proven to improve measures of diabetic control in studies lasting over a year, were discussed. My plant based slant was dismissed with the comment “Virta Health has amazing data and has become the plan of choice”. Although I respect my friend, I was concerned that his confidence was based on slick marketing and paltry science. Indeed, that is so and a rather scary skeleton was found in the closet of Virta Health and other keto authors using traditional approaches.
The Virta Health program has at its foundation a single study published in JMIR Diabetes (Journal of Medical Internet Research), a new e-site launch last year. All authors of this study disclosed a financial relationship with Virta Health and several also disclosed funding from Atkins Nutritionals, the National Dairy Council, and the Palm Oil Board. In short, 262 adults with DM2 were coached to follow a diet for 10 weeks described as having “total dietary carbohydrates 30 grams a day, protein of 1.5 grams/kg body weight, and dietary fats to satiety. Other aspects of the diet were individually prescribed to ensure safety, effectiveness, and satisfaction, including consumption of 3–5 servings of non-starchy vegetables and adequate mineral and fluid intake for the ketogenic state.” There was no control group. Only 238 patients completed the trial with a drop out of 10%. The findings included a baseline HgbA1C of 7.6% that fell by 1% in those who completed the study. One or more diabetes medication was reduced at the end of the trial in 57% of patients and body weight fell on average by 7%. Recently, 6 month follow-up of 108 of these subjects was reported on their website and show continued improvements in diabetic control.
The quality of this research program published in a e-journal not recognized as a leader, lacking a control group, experiencing a sizeable drop-out rate even though of short duration, and having 100% authorship with financial conflicts is of concern. For comparison, another research trial that used a low-fat plant based diet in patients with DM2 had a duration of 74 weeks, was published in a respected journal, had a control group, and had authors that had no corporate conflicts other than previously published books.
How about the skeleton in the closet of ketogenic diet programs like Virta Health?
First of all, the majority of medical articles about the impact of ketogenic diets are on children and adults with refractory epilepsy, a potential benefit of flooding the blood with ketone bodies recognized a century ago. However, these studies do not address mortality, DM2 or cardiovascular disease. The skeleton is multiple peer reviewed studies indicating a higher risk of premature DEATH on long term low carbohydrate diets like that recommended by Virta Health. Here is a list of the studies to know about before you shun “carbohydrates” from your diet.
1) Noto et al. This meta-analysis of 272,216 subjects studied for diet and mortality reported that the risk of “all-cause” mortality in those responding that they followed a low-carbohydrate diet was approximately 30% higher than other subjects.
2) Li et al. The Harvard School of Public Health studied over 4,000 men and women who had survived a heart attack. Those eating a lower carbohydrate diet higher in animal protein and fat was associated with a higher risk of all-cause and cardiovascular mortality. This increase was not identified in those responding they ate a plant-based low-carbohydrate diet.
3) Sjogren et al. In an analysis of over 900 elderly Swedish men, a Mediterranean diet pattern reduced mortality while a carbohydrate restricted diet was associated with a 20–40% increase in all-cause and cardiovascular mortality respectively.
4) Fung et al. In an analysis of nearly 130,000 subjects followed by the Harvard School of Public Health, subjects following an animal food based low carbohydrate diet had increase in all-cause, cardiovascular and cancer mortality while there was a reduction in mortality in those following a plant based similar diet pattern.
5) Snell-Bergeon et al. In a series of type 1 diabetics, a higher protein and fat diet was associated with more heart artery calcification, a marker of atherosclerosis, while a higher carbohydrate based diet was associated with a lower burden of artery calcification.
6) Lagiou et al. In a research group of over 42,000 Swedish women, respondents with a dietary pattern of higher protein and low-carbohydrate was associated with higher all-cause and cardiovascular mortality.
7) Trichopolou et al. In a Greek population of nearly 23,000 subjects, those following a low-carbohydrate and higher protein diet had higher all-cause, cardiovascular and cancer mortality.
These 7 studies from various locations and institutions around the world provide a sobering view of adopting a long-term low-carbohydrate diet supported by animal sourced protein and fat calories as is taught by Virta Health and others. The superior outcome with diets based in plant sources is a consistent finding.
Are there any dissenters? There are a few listed here.
1) Nakamura et al. A Japanese series of 9,200 men and women found a lower risk of cardiovascular and total mortality in women eating a “moderate diet lower in carbohydrate and higher in protein and fat” of any source.
2) Nilsson et al. In a study of over 77,000 Swedish citizens, a lower carbohydrate high protein diet was not associated with mortality.
3) Halton et al. In 82,000 plus women part of the Nurses Health Study, respondents with diets lower in carbohydrates and higher in protein and fat were not associated with an increased risk of cardiovascular disease.
The Virta Health website has an extensive section of citations of medical literature. It concerns me that the studies listed above are not amongst those citations for patients or physicians to consider. Virta Health holds out the promise of reversing DM2 but fails to mention the possibility of harm and even increased risk of mortality by long term use of the diet they advise based on other populations studied. Would patients sign up to reverse their DM2 if they were aware of these potential risks? Should they be informed of the concerns? Should authors and media experts promoting ketogenic diets for purposes other than refractory epilepsy notify their followers of these poor outcomes? Should plant-based low-carbohydrate plans, for 5 days a month like the fasting mimicking diet developed by Valter Longo, Ph.D. be the preferred option if this diet is selected?
Before drinking the Kool-Aid that the data supporting these programs are “amazing”, as my friend told me this week, these questions need an honest and open discussion.