What Does This Mean in the Long Run?
It's still too early to know how the ketogenic diet might affect your heart, Dr. Stamp explained. "Unfortunately, these answers do take time." She's referring to research — the diet is still relatively new, and without many long-term studies, it's difficult to know its impact.
"At this stage, most research on ketogenic diets has looked at some of the illnesses that lead to or happen in conjunction with heart disease, such as diabetes and obesity," she continued. "Research is still ongoing, but some researchers believe that a ketogenic diet is a useful way to manage diabetes and aid in weight loss — but this is still very much under investigation."
Dr. Harkin expressed a warier viewpoint. "While ketogenic diets can lead to short-term weight loss, there is no scientific evidence that this type of diet results in improved health or longevity," she said. "In fact, what we currently know indicates otherwise, with many reviews demonstrating increased cardiovascular death and all-cause mortality."
A recent study from The Lancet found that both high- and low-carb diets are associated with increased mortality, with 50 to 55 percent carbohydrate intake being the sweet spot. "This adds to the growing body of research showing that plant-based fats should be chosen whenever possible compared to animal-based fats," Dr. Harkin told POPSUGAR. She cited a portion of the study that found that mortality increased when carbohydrates were replaced with animal-derived fat or protein and decreased when the substitutions were plant-based.
However, Dr. Harkin doesn't believe the study provides enough evidence to support limiting your consumption of high-quality carbohydrates, like fruits, vegetables, whole grains, and beans. "The type of carbohydrate was not accounted for, and the studies analysed looked at various populations living in low-resource settings where, unfortunately, a large source of their diet relies on low-quality, refined carbohydrates," she said. "It makes sense that low-quality carbs (i.e. processed foods and refined grains), when replaced by high-quality, plant-derived fats and proteins, would result in improved morbidity and mortality."
Certified clinical nutritionist Autumn Bates, MS, agreed: "This study is by no means one to stake a claim on — there's no way to account for variables such as quality of the carbohydrates or fat eaten, as well as any other possible variables."