This human dietary intervention study with a cross-over design aims to compare the effects of two isocaloric diets - early time-restricted feeding (TRF) vs. late TRF - on glycemic control and lipid metabolism in overweight and obese women.
The participants are randomly allocated to one of two study groups: In study group (A) participants will begin with the early TRF (e-TRF) intervention. They will consume their habitual food (and the habitual daily amount of food) between 8 am and 4 pm for two weeks. After a washout-phase participants will conduct the late TRF (l-TRF) and consume their habitual food between 1 pm and 9 pm for another two weeks. Study group (B) receives the same interventions in the reversed order. Both dietary regimens will result in 8-hr eating period and 16-hr fasting period during the 24h day.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
31
Eat between 8 am and 4 pm for two weeks
Eat between 1 pm and 9 pm for two weeks
German Institute of Human Nutrition Potsdam-Rehbruecke
Nuthetal, Germany
Insulin sensitivity
Assessed using Matsuda index in oral glucose tolerance test (OGTT)
Time frame: 2 weeks
Glucose tolerance, fasting glucose, and overall daily glycemic variation
Assessed by glucose area under the curve in OGTT and using a continuous glucose monitoring (CGM)
Time frame: 2 weeks (OGTT) and 14 days (CGM)
Metabolic hormones and inflammatory markers
Levels of hormones related to the glucose metabolism, hormones of appetite regulation, adipokines and inflammatory markers
Time frame: 2 weeks
Oxidative stress markers
Malondialdehyde, 3-nitrotyrosine, and protein carbonyls
Time frame: 2 weeks
Blood lipids
Total cholesterol, low-density lipoprotein and high-density lipoprotein cholesterol and triglycerides
Time frame: 2 weeks
Blood pressure
Systolic and diastolic blood pressure
Time frame: 2 weeks
Liver enzymes
γ-glutamyltransferase (GGT), aspartate aminotransferase (ALT), and alanine aminotransferase (AST)
Time frame: 2 weeks
Anthropometric parameters: body weight
Body weight in kilograms
Time frame: 2 weeks
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Anthropometric parameters: BMI
BMI in kg/m\^2
Time frame: 2 weeks
Anthropometric parameters: waist circumference
Waist circumference in centimeters
Time frame: 2 weeks
Anthropometric parameters: fat and lean mass
Fat and lean mass in kilograms assessed by bioelectrical impedance analysis
Time frame: 2 weeks
Food intake: eating times
Eating times in hours and minutes as assessed by food records
Time frame: 14 days
Food intake: calorie intake
Calorie intake in kilocalories as assessed by food records
Time frame: 14 days
Food intake: macronutrient composition
Macronutrient composition in percentage of energy intake as assessed by food records
Time frame: 14 days
Satiety and hunger scores
Assessed using Visual Analog Scales (VAS with a scale of 1-100, where higher values correspond to stronger satiety/hunger)
Time frame: 2 weeks
Sleep quality and timing
Sleep quality as assessed by the Pittsburgh Sleep Quality Index (PSQI score, which ranges from 0-21, where higher values correspond to worse sleep quality) and by the ActiGraph device; sleep timing (sleep onset and offset) as monitored using a sleep diary
Time frame: 2 weeks (PSQI) and 14 days (ActiGraph, sleep diary)
Physical activity
24-h physical activity as monitored by an ActiGraph device
Time frame: 14 days
Expression of metabolic genes in adipose tissue
RNA-Seq analysis of subcutaneous adipose tissue samples
Time frame: 2 weeks
Social and economic decision behaviour
Assessed by computer tests together with the Barratt Impulsiveness Scale short version (BIS-15 with a score between 15 and 60, where higher values correspond to higher impulsiveness) and the UCLA Loneliness Scale (with a score between 20 and 100, where higher values correspond to higher subjectively perceived loneliness)
Time frame: 2 weeks