A Very Low Carbohydrate Diet Compared with the DASH Diet in Overweight or Obese Adults with Hypertension and Diabetes or Prediabetes

by | Jul 30, 2024 | Blood Pressure, Cardiovascular Health, Diabetes, Weight Control

Written by Harold Oster, MD. Results suggest that a very low-carbohydrate diet results in greater improvements in weight, glycemic control, and systolic blood pressure than the DASH diet.

The prevalence of obesity has increased worldwide. Obesity is often associated with hypertension, prediabetes, and diabetes, leading to an increased risk of stroke, heart disease, and premature death1-3. The Dietary Approaches to Stop Hypertension Diet (DASH) is often recommended to lower blood pressure in hypertensive patients. It also aids weight loss and improves glycemic control in diabetics4. A very low carbohydrate diet (VLC), also called the ketogenic diet, may have similar benefits in those who are overweight and obese5.

Laura R. Saslow, PhD et al. compared the effects of sixteen weeks on the DASH and VLC diets in overweight and obese adults with hypertension and diabetes or prediabetes. They also examined whether a multi-component behavioral support program provided additional benefits to either diet. The authors recruited patients with a body mass index between 25 and 50 kg/m,2 systolic blood pressure of 130 mm Hg or greater, and a hemoglobin A1C (HbA1C) of at least 5.7%. Ninety-four participants were randomized into four groups: the two diets, each with or without additional behavioral support. Participants in the VLC groups were asked to decrease their carbohydrate intake to twenty to thirty-five grams of non-fiber carbohydrates daily. In the DASH group, participants were encouraged to eat fruits and vegetables, lean meats and fish, whole grains, and low-fat dairy. They were also instructed to limit their daily sodium intake to less than 2,300 mg and their fat intake to less than 30% of total calories. All participants had access to a weekly online program to aid adherence to the diets. Participants assigned to additional behavioral support received information about mindfulness, social programs, and cooking skills. The participants were evaluated at baseline and sixteen weeks for blood pressure, weight, and HbA1C. Adherence to the diets was assessed by three dietary recalls. For the DASH diet, a scale of zero to ninety was created based on adherence to the individual recommendations of the diet, with a score of at least 40 indicating adherence. For the VLC diet, adherence was defined as eating no more than 90 g of non-fiber carbohydrates daily.

The authors noted the following:

  • Of the 94 participants at baseline, 85 completed the study.
  • Weight, blood pressure, and glycemic control improved in all groups.
  • In the intention-to-treat (ITT) analysis, the systolic blood pressure decreased more in the VLC groups than in the DASH groups. (9.77 mm Hg vs 5.18 mm Hg)
  • In the ITT analysis, weight decreased more in the VLC groups than in the DASH groups. (19.14 lbs vs 10.34 lbs)
  • HbA1C decreased more in the VLC groups than in the DASH groups. (0.35% vs 0.14%)
  • Adherence was 63.6% in the VLC group without additional behavioral support and 78.9% with support.
  • Adherence was 78.3% in the DASH group without support and 76.2% with support.
  • None of the outcomes were significantly different in those who received additional behavioral support compared to those who did not.
  • The results of those who completed the study did not significantly differ from the ITT analyses.

Results suggest that a very low carbohydrate diet results in greater improvements in weight, glycemic control, and systolic blood pressure than the DASH diet. The study’s limitations include its small sample size and the use of questionnaires to assess adherence to the diets.

Source: Saslow, Laura R., Lenette M. Jones, Ananda Sen, Julia A. Wolfson, Heidi L. Diez, Alison O’Brien, Cindy W. Leung et al. “Comparing very low-carbohydrate vs DASH diets for overweight or obese adults with hypertension and prediabetes or type 2 diabetes: a randomized trial.” The Annals of Family Medicine 21, no. 3 (2023): 256-263.

Click here to read the full text study.

Posted July 30, 2024.

Harold Oster, MD graduated from medical school in Miami, Florida in 1992 and moved to Minnesota in 2004. After more than 25 years of practicing Internal Medicine, he recently retired. Dr. Oster is especially interested in nutrition, weight management, and disease prevention. Visit his website at haroldoster.com.

References:

  1. Lin X, Li H. Obesity: Epidemiology, Pathophysiology, and Therapeutics. Front Endocrinol (Lausanne). 2021;12:706978. doi:10.3389/fendo.2021.706978
  2. Krist AH, Davidson KW, Mangione CM, et al. Screening for Hypertension in Adults: US Preventive Services Task Force Reaffirmation Recommendation Statement. Jama. Apr 27 2021;325(16):1650-1656. doi:10.1001/jama.2021.4987
  3. Harding JL, Pavkov ME, Magliano DJ, Shaw JE, Gregg EW. Global trends in diabetes complications: a review of current evidence. Diabetologia. Jan 2019;62(1):3-16. doi:10.1007/s00125-018-4711-2
  4. Azadbakht L, Fard NR, Karimi M, et al. Effects of the Dietary Approaches to Stop Hypertension (DASH) eating plan on cardiovascular risks among type 2 diabetic patients: a randomized crossover clinical trial. Diabetes Care. Jan 2011;34(1):55-7. doi:10.2337/dc10-0676
  5. Moriconi E, Camajani E, Fabbri A, Lenzi A, Caprio M. Very-Low-Calorie Ketogenic Diet as a Safe and Valuable Tool for Long-Term Glycemic Management in Patients with Obesity and Type 2 Diabetes. Nutrients. Feb 26 2021;13(3)doi:10.3390/nu13030758