clinical study to test the effects of a low-carbohydrate diet on body weight

Conditions: Obesity

Summary: the purpose of this study is to test the effects of a modified carbohydrate diet versus a portion controlled diet in overweight or obese men and women on body weight.


Eligibility criteria:
inclusion criteria: * men and women 18 to 65 years of age. * waist circumference measurement at visit 1 (week -1) of ³ 87 cm for females and ³ 90 cm for males. * subject agrees to discontinue all use of supplements or multivitamins (except for those provided during study period) by visit 2 (week 0). * normally active and judged to be in good health on the basis of medical history and routine laboratory tests. * subject must be willing to follow the assigned diet and maintain usual physical activity level throughout the trial. * subject understands the procedures and requirements of the study by providing written informed consent and authorization for protected health information disclosure. exclusion criteria: * weight loss of \> 10 lb in the two months prior to screening. * body mass index (bmi) \> 37.0 kg/m2. * current smoker (any cigarette use) or history of smoking within 6 months prior to screening. * postmenopausal women who are current users of hormone therapy or have discontinued hormone therapy within 2 months prior to screening. * history or presence of significant cardiac, renal, hepatic, pulmonary, biliary, or endocrine disorders. * uncontrolled hypertension (systolic blood pressure ³ 160 mm hg or diastolic blood pressure ³ 100 mm hg on two consecutive visits). * history of recurrent nephrolithiasis, or an acute episode of nephrolithiasis within the last year prior to screening. * history of symptomatic cholelithiasis, unless subject has undergone cholecystectomy. * history of gastrointestinal surgery for weight-reducing purposes. * active gastrointestinal disorders such as peptic ulcer disease or malabsorption syndromes (controlled lactose intolerance or gastroesophageal reflux disease are acceptable.) * pancreatic disease: pancreatic enzyme deficiency, history of pancreatitis. * fasting blood glucose ≥ 126 mg/dl at visit 1 or diagnosed diabetes mellitus. * use of any weight loss medications, supplements, programs, or meal replacement products intended to alter body weight within 4 weeks of the screening visit or during the course of the study. occasional use of meal replacement bars or shakes as snacks is acceptable. * history or presence of cancer in the past 2 years, except for successfully resected basal cell carcinoma of the skin. * psychiatric disorders requiring medications (i.e., selective serotonin reuptake inhibitors) or which could interfere with the subject's compliance to the requirements of the protocol. * history or current presence of any diagnosed eating disorders (binge eating, bulimia, history of anorexia). * use of systemic corticosteroids, androgens, or phenytoin. * use of pseudo-ephedrine during the study period. * use of lipid-lowering drugs or supplements, unless dose stable prior to enrollment (2 months prior for drugs, 2 weeks prior for supplements). * use of drugs for regulating hemostasis, other than stable dose aspirin. * use of thyroid hormones, except stable-dose replacement therapy for ≥ 2 months prior to enrollment. * abnormal laboratory test results of clinical significance, including, but not limited to total cholesterol \> 300 mg/dl or triglycerides \> 400 mg/dl. * females who are pregnant, planning to be pregnant during the study period, lactating, or women of childbearing potential who are not using an approved method of contraception. a woman is considered to be of childbearing potential unless she is post-hysterectomy, post-tubal ligation, or ³ 1 year postmenopausal. * recent history of (within past 12 months) or strong potential for alcohol or substance abuse. alcohol abuse will be defined as \> 14 drinks per week (1 drink = 12 oz beer, 4 oz wine, or 1 ½ oz distilled spirits). * participation in another clinical study within 30 days prior to screening visit (week -1). * individual has a condition the investigator believes would interfere with the evaluation of the subject or put the subject at undue risk.