Diabetes Dietary Study- Low Carbohydrate and Low-Fat Diets in Type 2 Diabetes

• Hemoglobin A1c [ Time Frame: 3 months, 6 months, 12 months ] [ Designated as safety issue: No ]
• Weight [ Time Frame: 3 months, 6 months, 12 months ] [ Designated as safety issue: No ]

• body composition [ Time Frame: 6 months, 12 months ] [ Designated as safety issue: No ]
• change in antidiabetic medications [ Time Frame: 3 months, 6 months, 12 months ] [ Designated as safety issue: No ]
• insulin sensitivity [ Time Frame: 6 months, 12 months ] [ Designated as safety issue: No ]
• lipids [ Time Frame: 6 months, 12 months ] [ Designated as safety issue: No ]
• dietary intake [ Time Frame: 6 months, 12 months ] [ Designated as safety issue: No ]
• physical activity [ Time Frame: 6 months, 12 months ] [ Designated as safety issue: No ]
• Quality of life [ Time Frame: 6 months, 12 months ] [ Designated as safety issue: No ]

The purpose of this study is to determine the effects of a low-carbohydrate diet compared to a low-fat/high-carbohydrate diet on glucose control in patients who have Type 2 Diabetes.

Obesity is not only a risk factor for type 2 diabetes but it also frequently increases the need for insulin requirement in people with type 2 diabetes who are overweight or obese. However, since insulin is a lipogenic hormone, insulin or sulfonylurea therapy that increases circulating insulin levels often results in additional weight gain. Controlled-carbohydrate "ketogenic" diets have been popular as an alternative way of losing weight, but little is known about the safety and efficacy of using a ketogenic approach in the management of overweight/obese patients with type 2 diabetes.

The proposed study will randomize a group of 126 overweight or obese (BMI > 25 and < 40) adults with type 2 diabetes to either a low-carbohydrate or a low-fat weight loss diet. The primary study endpoint will be six and twelve month changes in glycemic control as measured by hemoglobin A1c (HbA1c). Secondary endpoints include adiposity (BMI, body composition and fat distribution); blood glucose patterns (from self-monitoring records); change in antidiabetic medications (potential decrease in number and dosage), lipids, insulin sensitivity from a meal tolerance test, other metabolic markers (C-reactive protein, leptin) and participants' lifestyle (physical activity and diet) and perceptions of satiety, quality of life, mood, and well-being.

• Behavioral: low-carbohydrate diet
  ketogenic low-carbohydrate diet in patients with type 2 diabetes
• Behavioral: low-fat diet
  low-fat diet in patients with type 2 diabetes

• Experimental: 1
  low-carbohydrate diet
  Intervention: Behavioral: low-carbohydrate diet
• Active Comparator: 2
  low-fat diet
  Intervention: Behavioral: low-fat diet

• Cunningham C, Johnson S, Cowell B, Soroudi N, Segal-Isaacson CJ, Davis NJ, Isasi CR, Wylie-Rosett J. Menu plans in a diabetes self-management weight loss program. J Nutr Educ Behav. 2006 Jul-Aug;38(4):264-6. No abstract available.
• Davis NJ, Cohen HW, Wylie-Rosett J, Stein D. Serum potassium changes with initiating low-carbohydrate compared to a low-fat weight loss diet in type 2 diabetes. South Med J. 2008 Jan;101(1):46-9.
• Davis NJ, Tomuta N, Isasi CR, Leung V, Wylie-Rosett J. Diabetes-specific quality of life after a low-carbohydrate and low-fat dietary intervention. Diabetes Educ. 2012 Mar-Apr;38(2):250-5. Epub 2012 Feb 7.
• Davis NJ, Crandall JP, Gajavelli S, Berman JW, Tomuta N, Wylie-Rosett J, Katz SD. Differential effects of low-carbohydrate and low-fat diets on inflammation and endothelial function in diabetes. J Diabetes Complications. 2011 Nov-Dec;25(6):371-6. Epub 2011 Oct 27.
• Davis NJ, Tomuta N, Schechter C, Isasi CR, Segal-Isaacson CJ, Stein D, Zonszein J, Wylie-Rosett J. Comparative study of the effects of a 1-year dietary intervention of a low-carbohydrate diet versus a low-fat diet on weight and glycemic control in type 2 diabetes. Diabetes Care. 2009 Jul;32(7):1147-52. Epub 2009 Apr 14.

Inclusion Criteria:

• Diagnosis of type 2 diabetes
• HbA1c 7-10%
• BMI (kg/m2) > 25 and < 40 and weight < 280 lb.
• Skill at and willingness to perform capillary blood glucose self-monitoring ---Insulin (changed to long-acting basal during run-in) or sulfonylurea treatment

Exclusion Criteria:

• Age > 65
• Weight >280 lb
• Health conditions that may interfere with study participation or for which the study interventions may be contraindicated. These include: kidney stones or kidney disease (creatinine > 1.3 and 1.5 mg/dL for females and males, respectively; proteinuria > 300 ug/g creatinine); liver or gall bladder disease; significant heart disease (myocardial infarction in the past six months, prior or current evidence of congestive heart failure, other evidence of LV dysfunction) or other indices of active cardiac abnormalities, (angina, electrocardiogram evidence of ischemia or transmural myocardial infarction), significant anemia; and cancer (other than effectively treated non melanomatous skin cancer and surgically treated cervical cancer in situ).
• Current hypokalemia defined as serum potassium levels <3.5 mg/dL.
• Osteoporosis
• Type 1 diabetes (history of ketoacidosis or undetectable fasting C-peptide levels)
• History of severe or repeated hypoglycemia, or hypoglycemia unawareness. Lack of recourse to another person in the immediate vicinity in the unlikely event that they require outside assistance for severe hypoglycemia.
• Triglyceride levels > 400 mg/dL.
• Inability or unwillingness to comply with any aspects of the dietary and research protocol.
• Weight changes > 10 lbs in the past three months.
• History of binge eating disorder or other eating disorders.
• Pregnancy or intention to become pregnant in the next 12 months.
• Current oral hypoglycemic medication that raises the blood insulin level