A Randomized, Controlled Trial on Diet, Insulin Sensitivity, and Postprandial Metabolism
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 220
- 试验地点
- 2
- 主要终点
- Body weight in kg
研究概览
简要总结
This randomized, controlled trial aims to elucidate the mechanisms by which a plant-based dietary intervention causes weight loss. Using a low-fat, plant-based diet for 16 weeks, along with an untreated control for comparison, the study will measure changes in body weight, body composition, intramyocellular and/or intrahepatocellular lipid, and changes in association to body weight.
详细描述
In a 16-week trial, overweight adults will be randomly assigned to two groups. Changes in body weight, body composition, intramyocellular and/or intrahepatocellular lipid, and changes in association to body weight will be measured among other outcomes.
The Intervention Group will follow a low-fat, vegan diet and will receive weekly classes and support.
The Control Group will be asked to follow a conventional control diet.
This study conducts a pilot sub-study to test the hypothesis that changes in insulin sensitivity and beta-cell function observed in response to a diet intervention correlate with changes in intramyocellular and/or intrahepatocellular lipid. Another sub-study assesses the association between metabolic outcomes and gut microbiome. One additional sub-study is looking for associations between metabolic outcomes and endothelial function.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Men and women age ≥18 years of age
- •Body mass index 28-40 kg/m2
排除标准
- •Diabetes mellitus, type 1 or 2, history of diabetes mellitus or of any endocrine condition that would affect body weight, such as thyroid disease, pituitary abnormality, or Cushing's syndrome
- •Smoking during the past six months
- •Alcohol consumption of more than 2 drinks per day or the equivalent, episodic increased drinking (e.g., more than 2 drinks per day on weekends), or a history of alcohol abuse or dependency followed by any current use
- •Use of recreational drugs in the past 6 months
- •Use within the preceding six months of medications that affect appetite or body weight, such as estrogens or other hormones, thyroid medications, systemic steroids, antidepressants (tricyclics, monoamine oxidase inhibitors (MAOIs), selective serotonin reuptake inhibitors (SSRIs), antipsychotics, lithium, anticonvulsants, appetite suppressants or other weight-loss drugs, herbs for weight loss or mood, St. John's wort, ephedra, beta blockers
- •Pregnancy or intention to become pregnant during the study period
- •Unstable medical or psychiatric illness
- •Evidence of an eating disorder
- •Likely to be disruptive in group sessions
- •Already following a low-fat, vegan diet
- •Lack of English fluency
- •Inability to maintain current medication regimen
- •Inability or unwillingness to participate in all components of the study
- •Intention to follow another weight-loss method during the trial
结局指标
主要结局
Body weight in kg
时间窗: 16 weeks
Anticipated weight-loss for intervention group compared with control group. Weight and height will be combined to report BMI in kg/m\^2
Visceral fat in cm^3
时间窗: 16 weeks
Anticipated weight-loss for intervention group compared with control group.
Insulin resistance
时间窗: 16 weeks
Insulin resistance will be assessed by the Homeostatic Model Assessment (HOMA) index.
Resting Energy Expenditure (REE)
时间窗: 16 weeks
Participants will be asked to report to the laboratory within 60 minutes of waking and after a 12-hour fast. Following 30 minutes of quiet rest in a dimly lit room, pulse, respiratory rate, and body temperature will be measured. REE will be measured for 20 minutes through indirect calorimetry (COSMED Metabolic Company Quark Resting Metabolic Rate (RMR), Chicago, IL) utilizing a ventilated hood system. The laboratory temperature will be maintained at 23 degrees C throughout, and precautions will be taken to minimize any disturbances that could affect the metabolic rate. For premenopausal women, measures will be timed so as to occur in the luteal phase of the menstrual cycle.
Changes in intramyocellular and/or intrahepatocellular lipid
时间窗: 16 Weeks
A subset of participants will be selected for magnetic resonance (MR) spectroscopy studies quantifying hepatic lipid and/or intramyocellular and/or contents in order to provide data regarding possible causal relationships between dietary changes, ectopic lipid, and insulin sensitivity. Selected individuals with varying degrees of insulin-resistance in both groups will be assessed before and after the intervention period. These magnetic resonance spectroscopy (MRS) studies will take place at the Magnetic Research Center at Yale University School of Medicine, New Haven, CT.
Postprandial metabolism
时间窗: 16 weeks
Participants will be asked to report to the laboratory within 60 minutes of waking and after a 12-hour fast. Postprandial metabolism will be measured for three hours after the standard meal. For premenopausal women, measures will be timed so as to occur in the luteal phase of the menstrual cycle.
Fat mass in grams
时间窗: 16 weeks
Anticipated weight-loss for intervention group compared with control group.
次要结局
- Race Disparities(16 weeks)
- Food costs(16 weeks)
- Endothelial function(16 weeks)
- Levels of Advanced Glycosylation Endproducts (AGEs)(16 Weeks)
- Beta-cell function as measured by glucose (mmmol/L)(16 weeks)
- Beta-cell function as measured by insulin (pmol/L)(16 weeks)
- Beta-cell function as measured by C-peptide (ng/mL)(16 weeks)
- Dietary Advanced Glycation End Products (AGEs)(16 weeks)
- PDI, hPDI, uPDI(16 weeks)
- The Effect of Carbohydrate Quantity & Quality on Body Composition & Insulin Resistance(16 Weeks)
- Microbiome Analysis(16 weeks)
- Diet Assessment Recall Questionnaire(16 weeks)
- The Effect of Fat Quantity & Quality on Body Composition, Insulin Resistance, & Insulin Secretion(16 Weeks)
- The Effect of Protein Quantity & Quality on Body Composition, Insulin Resistance, & Insulin Secretion(16 Weeks)
- Ultraprocessed foods(16 weeks)