Research on "Metabolic Adaptation" in Obese People
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 发起方
- 入组人数
- 10
- 主要终点
- Fat-free mass
研究概览
简要总结
Obesity has become a global public health crisis, with 810 million adults classified as obese (BMI ≥ 30 kg/m²) worldwide in 2020. This number is projected to rise to 1.53 billion by 2035. China faces a particularly severe challenge, with one of the highest rates and fastest growth in obesity prevalence globally. Obesity is a well-established risk factor for numerous chronic diseases, including cancer, cardiovascular disease, and diabetes. As such, weight loss is essential for improving health outcomes and preventing related complications.
Lifestyle interventions-primarily dietary modifications and physical activity-are the cornerstone of obesity treatment, aiming to reduce weight by addressing energy intake and expenditure. Accumulating evidence indicates that energy imbalance is a key driver of obesity. However, resting metabolic rate (RMR), which accounts for approximately 60-75% of total energy expenditure, often declines during lifestyle interventions due to metabolic adaptation. This adaptive decrease in RMR can undermine weight loss efforts.
While both body composition and core body temperature are known to influence RMR, their specific roles in metabolic adaptation during lifestyle interventions remain poorly understood. This study aims to investigate the individual contributions of changes in body composition and fluctuations in core body temperature to the observed reduction in RMR during such interventions. By combining body composition analysis and continuous core temperature monitoring, the study seeks to uncover mechanisms underlying metabolic adaptation and identify potential targets for enhancing weight loss strategies.
详细描述
Body Composition and Related Measurements Height and Weight Measurement Fasting body weight and height will be measured using the Seca medical metric system (Seca 311231, Germany). Participants will wear a standardized disposable lab coat and stand barefoot on an electronic scale for accurate measurement. Barefoot height will be measured to the nearest millimeter using a Leicester stadiometer (Seca 217, Germany).
3D Body Scanning Participants will stand at the center of the Scanatic™ 360 3D scanning room and maintain proper posture. Trained staff will operate the scanner, sensors, and cameras to collect detailed anthropometric data, including waist and hip circumference.
Bioelectrical Impedance Analysis (BIA) Body composition will be assessed using the TANITA MC-980 device, which provides segmental weight measurements (right arm, left arm, trunk, right leg, left leg) and generates a detailed report including body weight (BW), body fat percentage (fat%), fat mass (FM), body mass index (BMI), and fat-free mass (FFM).
Dual-Energy X-ray Absorptiometry (DXA) DXA scanning (Horizon, Hologic) will be performed with participants wearing uniform disposable lab coats and without metal accessories. DXA uses a low-dose X-ray beam with two energy peaks-one absorbed by soft tissue and the other by bone-to differentiate tissue types. Software algorithms enable precise measurement of fat and fat-free mass.
BOD POD Before testing, participants will fast and avoid strenuous activity, smoking, and exercise for at least two hours. Participants will wear close-fitting swimwear (boxers for men; one-piece swimsuit for women), a swim cap, and no accessories. The BOD POD (GS-X, Cosmed) estimates body composition using air displacement, differentiating fat mass and fat-free mass based on body volume and density calculations.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 40 Years（Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- •BMI： ≥30kg/m2 Willing to participate in an 8-week weight-loss camp program
排除标准
- •Metabolic or cardiovascular diseases (such as diabetes) Mental disorders (such as depression and claustrophobia) Infectious diseases (such as AIDS, tuberculosis, malaria) High blood pressure Pregnant, lactating, or prepare for pregnancy Implanted or portable electro-mechanical device Taking antihypertensive or weight-loss medications
研究组 & 干预措施
Diet and Exercise intervention
Diet intervention：Provide a fixed amount of food every day Exercise intervention：Train every day according to a specific course schedule
干预措施: lifestyle intervention (Behavioral)
结局指标
主要结局
Fat-free mass
时间窗: About 8 weeks.
Fat-free mass in kilograms will be measured by DXA(Dual-Energy X-ray Absorptiometry). DXA scanning (Horizon, Hologic) will be performed with participants wearing uniform disposable lab coats and without metal accessories.
Total body water
时间窗: About 7 days.
Total body water in kilograms will be measured by deuterium dilution technique. Participants will fast for 10 hours and provide a baseline urine sample. A dose of deuterium-labeled water (5%deuterium, 95% H2O) will be administered based on body weight. For example, a 60 kg individual will receive 80.6 g of deuterated water. Urine samples will be collected at baseline, 3.5 hours post-ingestion, and one week later. Samples will be stored at -20℃ and analyzed at the Shenzhen Institutes of Advanced Technology, CAS. Deuterium enrichment typically increases from 150 ppm to 250 ppm and returns to baseline in 14-21 days.
Physical Activity
时间窗: About 10 weeks.
Daily activity will be tracked using a tri-axial accelerometer (ActiGraph GT3XP- BTLE, USA), worn continuously except during water-based activities. The device captures physical activity and sleep duration throughout the intervention.
Core Body Temperature
时间窗: About 3 days.
Core body temperature in degree centigrade will be measured by the e-Celsius ingestible capsule (BodyCap). The capsule is swallowed uner supervision and begins recording temperature approximately 4 hours after ingestion, once it reaches the intestines.
Food Intake
时间窗: About 8 weeks.
Food intake in grams will be measured by food scales. Volunteers will record food intake by photographing and weighing their meals. Provided with food scales, they will also use a card-sized object (similar to a bank card) for scale. Photos should include the food before and after eating, along with weight measurements and the card reference.
Total energy expenditure
时间窗: About 3 days.
Total energy expenditure will be measured using a metabolic chamber system (Maastricht Instruments, Netherlands), which operates on indirect calorimetry principles. The system monitors oxygen consumption and CO2 production continuously over 24 hours. Participants will stay in the chamber from 10 p.m. on Day 1 to 7 a.m. on Day 3. Breakfast will be provided at 20% of the daily energy requirement, following macronutrient recommendations: protein 15%, fat 25%, and carbohydrates 60%. For lunch and dinner, participants will self-select meals, which will be documented via photographs and weight measurements.
Weight
时间窗: About 8 weeks.
Fasting body weight in kilograms will be measured using the Seca medical metric system (Seca 311231, Germany). Participants will wear a standardized disposable lab coat and stand barefoot on an electronic scale for accurate measurement.
Waist circumference
时间窗: About 8 weeks.
Waist circumference in centimeters will be measured by 3D Body Scanner. Participants will stand at the center of the ScanatictTM 360 3D scanning room and maintain proper posture. Trained staff will operate the scanner, sensors, and cameras to collect detailed anthropometric data, including waist and hip circumference.
Fat mass
时间窗: About 8 weeks.
Fat mass in kilograms will be measured by TANITA MC-980 device and Inbody, which provides segmental weight measurements and generates a detailed report.
Fat%
时间窗: About 8 weeks.
Fat% will be measured by BOD POD (Air Displacement Plethysmography). Before testing, participants will fast and avoid strenuous activity, smoking, and exercise for at least two hours. Participants will wear close-fitting swimwear (boxers for men; one-piece swimsuit for women), a swim cap, and no accessories. The BOD POD (GS-X, Cosmed) estimates body composition using air displacement, differentiating fat mass and fat-free mass based on body volume and density calculations.
Food Intake
时间窗: About 8 weeks.
Food intake in grams will be measured by food scales. Volunteers will record food intake by photographing and weighing their meals. Provided with food scales, they will also use a card-sized object (similar to a bank card) for scale. Photos should include the food before and after eating, along with weight measurements and the card reference.
Total body volume
时间窗: About 8 weeks.
Total body volume in liters will be measured by MRI (United Imaging uMR790). Whole-body fat distribution will be assessed using the uMR790 MRI system (United Imaging Healthcare). No contrast agent is required. Participants will lie supine on the MRI bed while trained staff perform full-body scans from the neck to the knees using a rapid dynamic imaging sequence.
Total body water
时间窗: About 7 days.
Total body water in kilograms will be measured by deuterium dilution technique. Participants will fast for 10 hours and provide a baseline urine sample. A dose of deuterium-labeled water (5%deuterium, 95% H2O) will be administered based on body weight. For example, a 60 kg individual will receive 80.6 g of deuterated water. Urine samples will be collected at baseline, 3.5 hours post-ingestion, and one week later. Samples will be stored at -20℃ and analyzed at the Shenzhen Institutes of Advanced Technology, CAS. Deuterium enrichment typically increases from 150 ppm to 250 ppm and returns to baseline in 14-21 days.
Physical Activity
时间窗: About 10 weeks.
Daily activity will be tracked using a tri-axial accelerometer (ActiGraph GT3XP- BTLE, USA), worn continuously except during water-based activities. The device captures physical activity and sleep duration throughout the intervention.
Core Body Temperature
时间窗: About 3 days.
Core body temperature in degree centigrade will be measured by the e-Celsius ingestible capsule (BodyCap). The capsule is swallowed uner supervision and begins recording temperature approximately 4 hours after ingestion, once it reaches the intestines.
Total energy expenditure
时间窗: About 3 days.
Total energy expenditure will be measured using a metabolic chamber system (Maastricht Instruments, Netherlands), which operates on indirect calorimetry principles. The system monitors oxygen consumption and CO2 production continuously over 24 hours. Participants will stay in the chamber from 10 p.m. on Day 1 to 7 a.m. on Day 3. Breakfast will be provided at 20% of the daily energy requirement, following macronutrient recommendations: protein 15%, fat 25%, and carbohydrates 60%. For lunch and dinner, participants will self-select meals, which will be documented via photographs and weight measurements.
Height
时间窗: About 8 weeks.
Height in centimeters will be measured to the nearest millimeter using a Leicester stadiometer (Seca 217, Germany).
次要结局
未报告次要终点
研究者
John R. Speakman
Professor
Shenzhen Institutes of Advanced Technology ,Chinese Academy of Sciences