Can older patients adopt and maintain a ketogenic diet? An observational study in support of clinical trials in older patients.

Ketogenic diets appear promising for obesity, diabetes, cancer, and other illnesses. Because older patients are more likely to contend with such illnesses and because of a paucity of dietary outcomes among these patients, we examined ketogenic diets in older patients.This multisite study focused on patients (≥65 years of age) on a ketogenic diet. Medical records were identified with the keywords "keto," "ketogenic," and "Atkins." Records were reviewed in detail with extraction of direct quotations to substantiate observations.We report on 200 consecutive patients with a median age of 70 years. Reasons for diet included weight loss, diabetes, and cancer; the majority remained on the diet for >1 month. In 134 (67%: 95% confidence interval: 60, 73%), the ketogenic diet appeared beneficial: 93 of 117 (79%) who sought weight loss lost weight ("She has lost 15 pounds and plans to lose another 8"); 36 of 67 (54%) who sought glucose control appeared to achieve the latter ("He has gone on a ketogenic diet and has been able to bring his sugars down significantly"); and 5 of 8 (63%) who sought improved cancer outcomes appeared to derive them ("He attributes part of the control of his cancer and increased QOL to adopting the keto for cancer diet"). Adverse events occurred in 30 patients (15%): dyslipidemia (n = 14), constipation (n = 9), sub-therapeutic international normalized ratio (n = 3), pancreatitis (n = 2), diarrhea (n = 1), and fatigue (n = 1).Trials that test ketogenic diets for a variety of illnesses should enroll older adults.