Outcome
Type |
Measure |
Description |
Time frame |
Safety issue |
Primary |
Disposition index |
The primary objective of this study is to establish the effect of a metabolically targeted, optimal versus suboptimal macronutrient manipulated 12-week dietary intervention on the change in disposition index, a composite marker of first phase insulin secretion and insulin sensitivity during a 2-hour 7-points oral glucose tolerance test (OGTT). Disposition index will be calculated as follows: [Insulin sensitivity index (ISI) * (AUC30 min insulin / AUC30 min glucose)], where AUC30 min is the area under the curve between 0 and 30 minutes of the OGTT for insulin (pmol/l) and glucose (mmol/l), respectively, and ISI is defined as: [10,000 ÷ square root of (fasting plasma glucose (mmol/l) x fasting insulin (pmol/l)) x (mean glucose (mmol/l) x mean insulin (pmol/l))]. Higher values represent a higher insulin sensitivity. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Mean 24h glucose concentrations |
Optimal versus suboptimal diet. The mean 24h glucose concentrations will be measured continuously with the iPro2 device and Enlite Glucose Sensor (Medtronic) and expressed as mmol/L. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Glucose incremental area under the curve (iAUC) |
Optimal versus suboptimal diet. The iAUC will be calculated using the trapezoid rule from data obtained from the iPro2 device and Enlite Glucose Sensor (Medtronic). The iAUC provides a summary measure of the net increase in glucose levels above the fasting level during a 24-hour period and is expressed as mmol/min/L. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
The frequency and duration of hypo- and hyperglycemia |
Optimal versus suboptimal diet. The frequency and duration of hypo- and hyperinsulinemia will be monitored using the iPro2 device and Enlite Glucose Sensor (Medtronic) and is defined as a glucose level of =10.0 mmol/l for hyperglycemia, whilst hypoglycemia will be defined as a glucose concentration =3.9 mmol/l. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Glucose tolerance |
Optimal versus suboptimal diet. Determined by 2-hour glucose values (mmol/L) during an oral glucose tolerance test. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Muscle insulin sensitivity |
Optimal versus suboptimal diet. Determined during a 2-hour, 7-points oral glucose tolerance test. The muscle insulin sensitivity index (MISI) will be calculated as follows: MISI (mmol/l/min/pmol/l) = (dG/dt) / mean plasma insulin concentration (pmol/l) during OGTT. Here, dG/dt is the rate of decay of plasma glucose concentration (mmol/L) during the OGTT, calculated as the slope of the least square fit to the decline in plasma glucose concentration from peak to nadir. Higher values represent higher muscle insulin sensitivity. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Hepatic insulin sensitivity |
Optimal versus suboptimal diet. Determined during a 2-hour, 7-points oral glucose tolerance test. The hepatic insulin resistance index (HIRI) will be calculated using the square root of the product of the area under curves (AUCs) for glucose and insulin during the first 30 min of the OGTT - i.e., square root (glucose0-30 [AUC in mmol/l·h] · insulin 0-30 [AUC in pmol/l·h). Higher IR values represent lower hepatic insulin sensitivity. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Insulin sensitivity |
Optimal versus suboptimal diet. Glucose infusion rate (mg/kg/min) during a 2-step hyper-insulinemic euglycemic clamp as golden standard method. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Body composition |
Optimal versus suboptimal diet. Body composition will be determined by using a dual-energy X-ray absorptiometry scan (DXA). |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Waist circumference |
Optimal versus suboptimal diet. Waist circumferences in centimeters. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Hip circumferences |
Optimal versus suboptimal diet. Hip circumferences in centimeters. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Body fat distribution |
Optimal versus suboptimal diet. Magnetic Resonance Imaging (MRI)(UM) and Magnetic resonance spectroscopy (1H-MRS)(WUR) measurements will be included to quantify both subcutaneous and visceral fat depots, and ectopic fat deposition (e.g. in liver and muscle). |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Blood pressure |
Optimal versus suboptimal diet. Systolic and diastolic blood pressure in mmHg. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Fasting circulating metabolic markers |
Optimal versus suboptimal diet. Fasting circulating metabolic markers include: glucose, insulin, hemoglobin A1c (HbA1c), triacylglycerol, free glycerol, free fatty acids (FFA), lactate, high density lipoprotein (HDL), total cholesterol, short chain fatty acids (SCFA), bile acids, glucagon-like peptide-1 (GLP-1), peptide YY (PYY). |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Fasting blood lipid spectrum |
Optimal versus suboptimal diet. Metabolomics will be used to determine the fasting blood lipid spectrum. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Postprandial circulating metabolic markers |
Optimal versus suboptimal diet. Postprandial circulating metabolic markers will be determined during a high-fat mixed-meal test and include: glucose, insulin, triacylglycerol, free glycerol, free fatty acids (FFA), lactate, high density lipoprotein (HDL), total cholesterol, short chain fatty acids (SCFA), bile acids, glucagon-like peptide-1 (GLP-1), peptide YY (PYY). |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Energy expenditure |
Optimal versus suboptimal diet. Fasting and insulin-stimulated energy expenditure will be determined by indirect calorimetry during a 2-step hyperinsulinemic-euglycemic clamp. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Substrate oxidation |
Optimal versus suboptimal diet. Fasting and insulin-stimulated substrate oxidation will be determined by indirect calorimetry during a 2-step hyperinsulinemic-euglycemic clamp. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Fecal microbiota composition |
Optimal versus suboptimal diet. Fecal samples to be used for analysing microbiota composition will be collected. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Oral microbiota composition |
Optimal versus suboptimal diet. Saliva samples to be used for analysing microbiota composition will be collected. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Self-reported perceived stress |
Optimal versus suboptimal diet. Perceived stress will be assessed using a 10-item perceived stress scale (PSS-10). Items will be scored based on a 5-point Likert scale, with higher scores representing higher perceived stress levels. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Self-reported self efficacy in physical activity |
Optimal versus suboptimal diet. Self efficacy in physical activity will be assessed using Likert scales, determining an individual's ability to achieve performing physical activity. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Self-reported sleep behaviour |
Optimal versus suboptimal diet. Sleep behaviour will be assessed using the Munich Chronotype Questionnaire (MCTQ). |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Self-reported sleep quality over a 1 month period |
Optimal versus suboptimal diet. Sleeping quality will be assessed using the Pittsburgh Sleep Quality Index (PSQI). |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Self-reported daytime sleepiness |
Optimal versus suboptimal diet. Daytime sleepiness is assessed using the 8-item Epworth Sleepiness Scale (ESS). Items will be scored on a scale of 0-3, with a higher score representing a higher probability of falling asleep. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Self-reported fatigue |
Optimal versus suboptimal diet. Self-reported fatigue will be assessed using the Chalder Fatigue Scale. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Self-reported sedentary behaviour |
Optimal versus suboptimal diet. Sedentary behaviour will be assessed using the sedentary behaviour questionnaire (AQUAA). |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Self-reported physical activity |
Optimal versus suboptimal diet. Self-reported physical activity will be assessed using the physical activity questionnaire (Baecke). |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Self-reported eating rate |
Optimal versus suboptimal diet. Self-reported eating rate will be assessed using the eating rate index. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Self-reported intestinal health |
Optimal versus suboptimal diet. Self-reported intestinal health will be assessed using an intestinal health questionnaire and the Bristol Stool Chart. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Self-reported quality of life |
Optimal versus suboptimal diet. Self-reported quality of life will be assessed using the 36-Item Short Form Health Survey (SF-36). Higher scores represent less disability. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Physical activity patterns |
Optimal versus suboptimal diet. Physical activity patterns will be monitored continuously with the ActivPAL3 device. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Cognitive performance |
Optimal versus suboptimal diet. Cognitive function will be assessed using the Cambridge Neuropsychological Test Automated Battery. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Subcutaneous adipose tissue biopsy |
Optimal versus suboptimal diet. Subcutaneous adipose tissue biopsies will be taken for histology and gene and protein expression analysis. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Skeletal muscle biopsy |
Optimal versus suboptimal diet. Skeletal muscle biopsies will be taken for histology and gene and protein expression analysis. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Advanced glycation end-product (AGE) accumulation |
Optimal versus suboptimal diet. AGE accumulation will be measured by skin autofluorescence using an AGE reader (Diagnoptics) |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Fasting immune metabolism (PBMCs) |
Optimal versus suboptimal diet. Assessment of PBMCs as measure of fasting immune metabolism |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Carotid artery reactivity |
Optimal versus suboptimal diet. Assessment of (peripheral) vascular function by carotid artery reactivity (CAR) in response to a cold pressor test. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Food preferences |
Optimal versus suboptimal diet. Food preferences will be assessed by using the computer-based Macronutrient and Taste Preference Ranking Task (MTPRT). |
Change from baseline at week 12 dietary intervention |
|
Secondary |
Intervention effects on all above outcomes within the LIR and MIR group. |
In contrast to the other outcomes, the intervention effect within the MIR and LIR group will be analysed for all above mentioned outcomes (as compared to an analysis of optimal versus the suboptimal diet). MIR and LIR are two measures of insulin resistance, in primarily the muscle and liver, respectively. MIR and LIR can be modelled from an OGTT, as described above. Thus, for each of the outcomes described above, their change following 12 weeks of dietary intervention will be compared between the two metabolic phenotypes, MIR and LIR. |
Change from baseline at week 12 dietary intervention |
|
Secondary |
DNA analysis |
Buffy coats will be collected for DNA analysis, pre-intervention only. |
Baseline |
|