Keto: Fad Diet or Health Benefit?
Diane Vizthum, MS, RD, CSSD, LDN
Johns Hopkins Institute for Clinical and Translational Research
Vizthum D. Keto: fad diet or health benefit? [published online March 13, 2019]. Cardiology Consultant.
“Keto diet” was the most-searched diet term on Google in 2018.1 If it has not happened already, your patients will soon start asking, “Should I do keto?” Although the specifics can vary, ketogenic eating patterns generally recommend consuming a diet that is high fat, moderate protein, and very low carbohydrate. Carbohydrate intake is often less than 20 g of net carbohydrate (total carbohydrate minus fiber) or 5% of calories per day. The goal of this strict restriction is to get the body into a state of ketosis.
What Does the Data Say?
Patients tend to be interested in ketogenic diets for weight loss, and studies that typically last 1 to 2 years show that patients randomly assigned to low-carbohydrate or ketogenic diets tend to lose slightly more weight than those randomly assigned to other diets.2,3,4,5 It is theorized that being in ketosis helps with appetite regulation and improves fat burning, and that high dietary fat intake increases satiety. However, research also shows that weight loss is highly variable and tends to be greatest among people who are most adherent to dietary changes, regardless of what eating pattern they are following.6,7
In addition to potential weight loss, ketogenic diets also typically result in decreased blood sugar, triglycerides, and blood pressure and increased high-density lipoprotein cholesterol. Total cholesterol and low-density lipoprotein cholesterol tend to decrease or remain stable, especially among patients who have lost weight, although individual differences exist.8,9,10,11
Low-carbohydrate, high-fat diets are well-established in the treatment of epilepsy and are currently being researched in the treatment of other neurological conditions, including Alzheimer disease and brain tumors.12,13,14,15
Ketogenic diets are not recommended for women who are pregnant or nursing and patients with kidney, liver, or heart disease or eating disorders. Side effects could include dehydration, constipation, vomiting, or, in rare cases, kidney stones. Bone health should be monitored over time. Research into the impact of these diets on long-term cardiovascular health, advanced cardiovascular markers, and the microbiome is ongoing.
Implementing Ketogenic Diets in Practice
Ketogenic diets are extremely strict and require diligence in planning meals and tracking nutrients. Patients should work with their doctor and dietitian to determine if their potential benefits are worth the costs. Patients can certainly experiment with the diet if they would like to see how it makes them feel and how it impacts their health. However, this (or any) diet should not be viewed as a “quick fix.”
A doctor should closely monitor all patients who decide to start a ketogenic diet. If the patient is taking medication to lower blood glucose or blood pressure, the dose will likely have to be adjusted. Labs and bone health should be monitored.
A registered dietitian should also help patients ensure they are meeting their nutritional needs. There is a wide range of foods that people can eat and still be technically following the diet and producing ketones. Individuals could be eating a diet of quality foods that includes vegetables, nuts, healthy oils, avocados, meat, fish, eggs, and cheese. Or the diet could be highly processed and deficient in many micronutrients. A multivitamin is always recommended, and additional supplementation or diet adjustments may be needed. Any time multiple food groups are restricted, it is possible for deficiencies to develop without careful planning.
Ketogenic diets can be presented as an option to individuals who could benefit and in whom it is not contraindicated. Some patients do very well on the diet, but it is not for everyone and it is not always necessary. Practitioners should work with patients’ goals and preferences to help them find a long-term sustainable eating pattern that will maximize health and quality of life.
Diane Vizthum, MS, RD, CSSD, LDN, is a research nutritionist and dietitian at The Johns Hopkins Institute for Clinical and Translational Research in Baltimore, Maryland. She was also voted Young Dietitian of the Year in 2015 by the Maryland Academy of Nutrition and Dietetics.
- Year in Search 2018. Google Trends. https://trends.google.com/trends/yis/2018/US/. Accessed January 10, 2019.
- Bueno NB, de Melo IS, de Oliveira SL, da Rocha Ataide T. Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomized controlled trials. Br J Nutr. 2013;110(7):1178-1187. https://doi.org/10.1017/S0007114513000548.
- Gardner CD, Kiazand A, Alhassan S, et al. Comparison of the atkins, zone, ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A to Z weight loss study: a randomized trial. JAMA. 2007;297(9):969-977. doi:10.1001/jama.297.9.969.
- Saslow LR, Mason AE, Kim S, et al. An online intervention comparing a very low-carbohydrate ketogenic diet and lifestyle recommendations versus a plate method diet in overweight individuals with type 2 diabetes: a randomized controlled trial. J Med Internet Res. 2017;19(2):e36. https://doi.org/10.2196/jmir.5806.
- Hession M, Rolland C, Kulkarni U, Wise A, Broom J. Systematic review of randomized controlled trials of low-carbohydrate vs. low-fat/low-calorie diets in the management of obesity and its comorbidities. Obes Rev. 2009;10(1): 36-50. https://doi.org/10.1111/j.1467-789X.2008.00518.x.
- Alhassan S, Kim S, Bersamin A, King AC, Gardner CD. Dietary adherence and weight loss success among overweight women: results from the A to Z weight loss study. Int J Obes. 2008;32(6): 985-991. https://doi.org/10.1038/ijo.2008.8.
- Bray GA, Siri-Tarino PW. The role of macronutrient content in the diet for weight management. Endocrinol Metab Clin N Am. 2016;45(3): 581-604. https://doi.org/10.1016/j.ecl.2016.04.009.
- Lifestyle management: standards of medical care in diabetes—2019. Diabetes Care. 2019;42(Suppl. 1):S46-S60. https://doi.org/10.2337/dc19-S005.
- Cervenka MD, Patton K, Eloyan A, Henry B, Kossoff EH. The impact of the modified Atkins diet on lipid profiles in adults with epilepsy. Nutr Neurosci. 2016;19(3):131-137. https://doi.org/10.1179/1476830514Y.0000000162.
- Sharman MJ, Kraemer WJ, Love DM, et al. A ketogenic diet favorably affects serum biomarkers for cardiovascular disease in normal-weight men. J Nutr. 2002;132(7):1879-1885. https://doi.org/10.1093/jn/132.7.1879.
- Dashti HM, Al-Zaid NS, Mathew TC, et al. Long term effects of ketogenic diet in obese subjects with high cholesterol level. Mol Cell Biochem. 2006;286(1-2):1-9. https://doi.org/10.1007/s11010-005-9001-x.
- Krikorian R, Shidler MD, Dangelo K, Couch SC, Benoit SC, Clegg DJ. Dietary ketosis enhances memory in mild cognitive impairment. Neurobiol Aging. 2012;33(2):425.e19-27. https://doi.org/10.1016/j.neurobiolaging.2010.10.006.
- Taylor MK, Sullivan DK, Mahnken JD, Burns JM, Swerdlow RH. Feasibility and efficacy data from a ketogenic diet intervention in Alzheimer's disease. Alzheimers Dement. 2017;4:28-36. https://doi.org/10.1016/j.trci.2017.11.002.
- Woolf EC, Syed N, Scheck AC. Tumor metabolism, the ketogenic diet, and β-Hydroxybutyrate: novel approaches to adjuvant brain tumor therapy. Front Mol Neurosci. 2016;9:122. https://doi.org/10.3389/fnmol.2016.00122.