Science Update

New Review Investigates the Impact of a Ketogenic Diet in Patients with Obesity and Type II Diabetes

In a meta-analysis published this week in Nutrients, researchers investigated the impact of a ketogenic diet and its effects on specific metabolic biomarkers in patients with obesity and type II diabetes. By restricting carbohydrate intake, ketogenic diets reduce insulin levels which redirect lipid metabolism, resulting in a shift to ketone utilization as an alternative energy source instead of glucose. Ketones serve as non-carbohydrate energy sources that are converted from fatty acids in the body and are generated by limiting carbohydrates to 5% to 10% of total daily dietary requirements.

This review consisted of 14 randomized controlled trials including 734 patients who were overweight or obese, 444 diabetic patients, and 290 non-diabetic patients. The primary laboratory assessment included fasting glucose, HA1c, fasting insulin, C-peptide, total cholesterol, triglyceride, LDL cholesterol, HDL cholesterol, C-reactive protein (CRP), and serum creatinine. Bodyweight, body mass index (BMI), waist circumference, systolic blood pressure, and diastolic blood pressure were also collected. The effects of a ketogenic diet on glycemic control over a 3 to 12-month period were greater in patients with diabetes compared to low-fat diets. This was demonstrated by a significant reduction in HA1c levels and homeostatic model assessment (HOMA) values for diabetic patients. Similar effects were seen with both diets in nondiabetic patients. In addition, ketogenic diets of 4 weeks to 12 months demonstrated significant weight reductions in both diabetic and nondiabetic patients. Also, lipid profiles were improved in diabetic patients including an increase in HDL cholesterol and lower triglyceride levels.

These outcomes demonstrate the effectiveness of a ketogenic diet over a low-fat diet in improving metabolic biomarkers associated with glycemic, weight, and lipid controls in patients who are overweight, especially those with diabetes.

This is the first study to perform a meta-analysis with randomized controlled trials investigating the impact of ketogenic diets on glycemic control, weight loss, lipid control, and cardiovascular and renal risk markers over varied low-fat diets.

Ketogenic diets are an effective strategy for weight loss; however, transitioning to a ketogenic diet can be a challenge as the body is switching from oxidizing glucose to fat for energy production. Many individuals often experience fatigue, nausea, dizziness, and irritability during this transition.

Perceived hunger is also a common barrier to weight loss. Based upon this recent research exogenous ketones may serve as a valuable adjunct to a ketogenic diet, intermittent fasting, or for individuals transitioning to a ketogenic diet for weight loss. Exogenous ketone supplementation supports favorable ketone levels and promotes normal appetite as they facilitate healthy ghrelin function, which may reduce cravings

Source: Choi Y, Jeon S, and Shin S. Impact of a Ketogenic Diet on Metabolic Parameters in Patients with Obesity or Overweight and with or without Type 2 Diabetes: A Meta-Analysis of Randomized Controlled Trials. Nutrients. 6 July 2020, 12(7), 2005.