Before you jump on the "keto" train...
...consider the pros and cons.
If you keep up with nutrition trends, then you’ve most likely heard about the ketogenic or "keto" diet. The diet started in the 1920's as an effective medical treatment for children with epilepsy to prevent seizures. However, over the years its popularity has increased as a diet for weight loss (4).
What is the ketogenic diet?
The ketogenic diet is a low-carbohydrate, high-fat diet that that pushes the body to a state of ketosis. Ketosis occurs when the body is deprived of carbohydrates (the body's preferred energy source) and must make ketone bodies as an alternate source of energy. The American Diabetes Association classifies diets with less than 130 grams of carbs or less than 26% of calories from carbohydrates as ketogenic diets. However, many ketogenic proponents suggest modified versions with as little as 30 grams of carbs per day or less than 6% calories from carbs (2). For perspective, the current recommendations, or Acceptable Macronutrient Distribution Ranges (AMDR), from the Institute of Medicine advise obtaining 45-65 percent of calories from carbohydrates and 20-35 percent from fat.
Which recommendations should you follow?
The AMDR recommendations were established based on the review of evidence-based scientific literature and were formulated to promote optimal health. So why is there such a large disparity between these recommendations and the ketogenic trend? Is keto a magical panacea for weight loss or is it a potentially dangerous health fad?
Research shows that the ketogenic diet can be an effective tool for short-term weight loss due to calorie reduction, increased feeling of fullness from fats and protein, potentially decreased appetite from ketosis, and increased caloric need from converting non-carbohydrate energy sources to glucose (1). However, as mentioned above, this weight loss may be short-lived. Some studies show that those following a keto diet lose more lean mass than their non-keto counterparts and they may have more trouble keeping weight off long term (2, 3). One review found that subjects on low-carb diets were more likely to have fat stored around their organs, which can lead to problems like non-alcoholic fatty liver disease (2).
Ketogenic diets may initially help with glucose control for folks with diabetes since they're decreasing carbohydrate intake so drastically. However, in a prospective cohort of non-diabetic men, health professionals younger than 65 years old followed during 20 years, a low-carbohydrate diet high in animal proteins and fats was associated with a two-fold increased risk of type 2 diabetes. On the other hand, a low-carbohydrate diet high in vegetable proteins and fats was associated with a decreased risk of type 2 diabetes (3).
Outcomes related to cardiovascular disease (CVD) like cholesterol, triglycerides, and blood pressure show mixed results. These results may be inconsistent because the types of fats (saturated versus unsaturated) and carbohydrate (simple versus complex) subjects consume can vary greatly. A ketogenic diet composed of unsaturated fatty acids (from plants) may protect the heart while ketogenic diets consisting of saturated (from animals) and processed fats may contribute to heart disease. Similarly, carbohydrates consisting of fruits, vegetables and whole grains are cardio-protective compared to processed carbohydrates and added sugars.
Some research found that the diet reduces negative markers for insulin sensitivity, LDL cholesterol, triglycerides, and total cholesterol, while increasing HDL cholesterol (1, 6). However, other research shows decreased insulin sensitivity (therefore, higher risk of diabetes and increased blood sugar), higher LDL and lower HDL cholesterol levels (8). Despite some studies showing beneficial outcomes, there is evidence that does not favor the long-term outcomes of the ketogenic diet. One review of over 17 different studies found a significant increased in all-cause mortality in those who followed the ketogenic diet (3). Epilepsy studies in children who used the ketogenic diet as treatment found an increased risk of kidney stones, osteoporosis, hyperlipidemia, and impaired growth (2).
Here are some takeaways:
The ketogenic diet is surrounded by a lot of split research and may have potential in helping certain medical conditions like treating epilepsy and aiding in short-term weight loss.
The types of carbohydrates and fats consumed are more important than the ratio of carbohydrate to fats. Whether high or low-carb, choose a diet that prioritizes fruits, vegetables, whole grains, legumes, and nuts and seeds. Eliminate high saturated fat products like meats, dairy and poultry and limit intake of refined sugars and flours.
A plant-based ketogenic diet may be better for attaining weight loss while maintaining heart health (1, 2, 3). For optimal heart health, consume unsaturated, plant-based sources of fats like nuts, seeds and avocados instead of saturated fat-based sources from animal products. That said, it may be difficult to follow the low carbohydrate recommendations of the keotgenic diet long term.
If you choose to follow the ketogenic diet, be aware of potential nutrient deficiencies. Cutting out large groups of nutrients like whole grains and legumes may put you at risk for several micronutrient deficiencies such as B vitamins, vitamin E and folate.
Ketogenic diets are likely to be low in fiber. Legumes and whole grains are very limited on a keto diet, if eaten at all, which may result in insufficient fiber intake. Fiber intake of 25-30 grams a day has been shown to aid in weight loss, decrease cholesterol, reduce risk of cancer and improve gut health. See this post and eat all the fiber.
Research shows that whole-food, plant-based diets are more sustainable for long term weight loss, cancer prevention, heart health and much more. See 53 benefits of plant-based eating here.
Lastly, remember that promises of magic cures and amazing results may be scientifically skewed. Proceed with caution and always look at the organizations or companies who are supporting the diets and research behind them.
If you're looking for a weight loss plan with an abundance of evidence-based research supporting cardio-protective, cancer- preventative and anti-inflammatory benefits, a whole food plant-based diet is best. The American Institute for Cancer Research recommends eating a plant-based diet and reducing red and processed meat consumption for cancer prevention. They note that women who consume high fat diets, in particularly saturated fat, prior to a breast cancer diagnosis may have increased risk of dying from the disease (6). Conversely, research shows a plant-based diet can help prevent cancer while losing weight, reducing blood pressure, decreasing cholesterol, lowering HbA1C levels, and increasing insulin sensitivity (5).
Nutrition research is consistently evolving and changing, but if there is one established claim, it's that we all need to be eating more plants. A diet that is centered around these fiber-rich, nutrient-dense foods simply equates to better long-term health and quality of life.
-Susana Morphis, Georgia State Dietetic Intern
1. HM Dashti, TC Mathew, T Hussein, et al. Long-term effects
of a ketogenic diet in obese patients. Exp Clin Cardiology. 2004;9(3):200-205.
2. Kosinski, C., & Jornayvaz, F. (2017). Effects of Ketogenic Diets on Cardiovascular Risk Factors: Evidence from Animal and Human Studies. Nutrients,9(5), 517. doi:10.3390/nu9050517
3. De Koning L., Fung T.T., Liao X., Chiuve S.E., Rimm E.B., Willett W.C., Spiegelman D., Hu F.B. Low-carbohydrate diet scores and risk of type 2 diabetes in men. Am. J. Clin. Nutr. 2011;93:844–850. doi: 10.3945/ajcn.110.004333.
4. Noto H, Goto A, Tsujimoto T, Noda M (2013) Low-Carbohydrate Diets and All-Cause Mortality: A Systematic Review and Meta-Analysis of Observational Studies. PLoS ONE 8(1): e55030. doi:10.1371/journal.pone.0055030
5. Paoli, A., Rubini, A., Volek, J. S., & Grimaldi, K. A. (2014). Beyond weight loss: A review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. European Journal of Clinical Nutrition,68(5), 641-641. doi:10.1038/ejcn.2014.47
6. Tuso, P. (2013). Nutritional Update for Physicians: Plant-Based Diets. The Permanente Journal, 17(2), 61-66. doi:10.7812/tpp/12-085
7. Vegetarian and vegan. (n.d.). Retrieved from http://www.aicr.org/patients-survivors/healthy-or-harmful/vegetarian-and-vegan.html
8. Ellenbroek J.H., van Dijck L., Tons H.A., Rabelink T.J., Carlotti F., Ballieux B.E., de Koning E.J.P. Long-term ketogenic diet causes glucose intolerance and reduced B- and a-cell mass but no weight loss in mice. Am. J. Physiol. Endocrinol. Metab. 2014;306:E552–E558.
Susana Morphis is obtaining her Masters degree in Nutrition in Georgia State University's Coordinated Program. She loves to cook and bake healthy (and not so healthy) foods, and can't wait to become a registered dietitian.