An observational study in Nutritional and Metabolic Diseases, Prediabetes and Type 2 Diabetes, sponsored by German Institute of Human Nutrition. Recruiting at 1 site in Germany. Open to participants aged 40 Years to 75 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-09.
Sponsored by German Institute of Human Nutrition · Observational
Glycemic responses vary significantly among individuals, even when consuming identical foods or meals, but the factors predicting individual glucose response to food intake remain poorly investigated.
The aim of the LIfestyle MEtabotype study (LIME) observational study is to identify lifestyle-related and mechanistic factors which predict individual postprandial glucose fluctuations in individuals with different glycemic status (prediabetes, type 2 diabetes [T2D], and absence of prediabetes or T2D). To address this aim, the study will conduct a comprehensive lifestyle characterization and metabolic, molecular and neurocognitive phenotyping during study center visits and a dietary, glucose, sleep and activity monitoring during the observational phase.
Studies show that glycemic responses vary significantly among individuals, even when consuming identical foods or meals. These varying glycemic responses are attributed to metabolic differences between individuals. Recently, machine learning models incorporating metabolic data (including microbiome composition) have been able to successfully predict individual blood glucose responses. Precision nutrition recommendations based on such predictions could facilitate better glycemic control and reduce the risk of diabetes. From this perspective, considering metabolic biomarkers, phenotype and genotype, as well as gut microbiome composition, could play a role in deriving dietary recommendations and thereby achieving the best possible health outcomes through nutrition. In addition to macronutrient composition, the timing, frequency and number of meals may also play a significant role in the glycemic response to diet. Finally, socioeconomic, cultural and personal lifestyle factors also have an influence on the glycemic response. Therefore, this study aims to characterize the personal lifestyle differences between individuals with prediabetes, T2D, and those without prediabetes or T2D.
Furthermore, ketone bodies, specifically β-hydroxybutyrate (βHB), are gaining importance, as they serve as both metabolic biomarkers and alternative energy sources in periods of low carbohydrate availability. In individuals with insulin resistance or prediabetes, cerebral glucose utilization is often impaired; leading to the use of ketone bodies as a compensatory energy source for the brain. Findings indicate that the individual ketone response to dietary interventions varies significantly between individuals and could thus itself be relevant as a metabolic phenotype marker in the context of precision nutrition. Therefore, the study also aims to further investigate the extent to which exogenous βHB supplementation influences neurocognitive processes and decision-making behavior, and whether characteristic neurocognitive phenotypes can be derived from this in metabolic risk groups.
This study will achieve its aims by completing a comprehensive lifestyle characterization and metabolic, molecular and neurocognitive phenotyping of individuals with different glycemic status (prediabetes, type 2 diabetes [T2D], and absence of prediabetes or T2D) in a German cohort. The study consists of modules A and B.
This record represents a description of module A which includes a 14-days observational period at home and two visits (screening and phenotyping visits) of the study center at the German Institute for Human Nutrition Potsdam-Rehbrueke before and after the observational period, respectively. In the observation period, food intake, sleep, activity, and interstitial glucose will be monitored during 14 days, and test meals will be consumed at two days at specific times. Study visits of module A include the intensive characterization using questionaries, anthropometric and metabolic assessments as well as collection of biosamples.
Module B has an interventional crossover design and is registered an a separate record. Module B takes place 1-12 weeks after module A and include two visits of the study center at the Free University of Berlin, separated by a two-week interval. Study visits of module B will focus on neurocognitive phenotyping including MRI of brain anatomy, function and complete computer-based decision-making behavior tests, and a consumption of the test drink containing ketone β-hydroxybutyrate (βHB) (test and placebo visits).
The aims of the study are as follows:
Primary aims:
Secondary aim:
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Adults (40-75 years) with overweight or obesity and with prediabetes or T2D or without prediabetes and T2D
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
HbA1c \<5.7% and fasting plasma glucose \< 100 mg/dl
HbA1c 5.7-6.4%, or fasting plasma glucose 100-125 mg/dL
HbA1c ≥6.5%, fasting plasma glucose ≥ 126 mg/dl, or existing T2D diagnosis by physician, or T2D diagnosis based on an available result from standardized 75 g oral glucose tolerance test
Glucose incremental Area Under the Curve (iAUC) after a morning test meal
Glucose iAUC \[mg/dL⋅min\] measured using continuous glucose monitoring (CGM) after a standardized morning test meal as an average of two test days within the observation period
Time frame: 3 and 10 days
Body height
Body height \[m\] measured using a stadiometer or calibrated wall-mounted measuring tape
Time frame: 2 weeks
Body weight
Body weight \[kg\] measured by scale weight
Time frame: 2 weeks
Waist and hip circumference
Waist and hip circumference \[cm\] measured using tape
Time frame: 2 weeks
Body Mass Index (BMI)
BMI \[kg/m2\], calculated as weight/square height
Time frame: 2 weeks
Body composition
Fat and muscle mass \[kg\] measured by bioelectrical impedance analysis (BIA)
Time frame: 2 weeks
Basal metabolic rate
Basal metabolic rate \[kcal/day\] assessed by indirect calorimetry
Time frame: 2 weeks
Handgrip strength
Maximal isometric handgrip strength \[kg\] as measured by a hand-dynamometers
Time frame: 2 weeks
Blood pressure
Systolic and diastolic blood pressure \[mm Hg\], as measured by a blood pressure monitor
Time frame: 2 weeks
Fasting glucose
Glucose levels \[mg/dL\] assessed in fasting blood samples
Time frame: 2 weeks
HbA1c
HbA1c levels \[%\] assessed in fasting blood samples
Time frame: 2 weeks
Concentration of metabolic hormones
Insulin, C-peptide, glucagon, leptin and adiponectin levels \[ng/mL\] assessed in fasting blood samples
Time frame: 2 weeks
Concentration of blood lipids
Total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein cholesterol (HDL), triglycerides \[mg/dL\] and lipidomic-based lipid patterns assessed in fasting blood samples
Time frame: 2 weeks
Concentration of inflammatory markers
Interleukin-6 and hsCRP levels \[mg/L\] measured in blood samples
Time frame: 2 weeks
Concentration of liver enzymes
γ-glutamyltransferase (GGT), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels \[U/L\] determined in fasting blood samples
Time frame: 2 weeks
Concentration of kidney parameters
Creatinine, urea, uric acid levels \[mg/dL\] determined in fasting blood samples
Time frame: 2 weeks
Concentration of blood metabolites
Metabolite levels measured by metabolomic analysis in blood samples
Time frame: 2 weeks
Gene expression in blood mononuclear cells (PBMC)
Gene expression assessed by RNA-Seq or qPCR analysis in PBMC
Time frame: 2 weeks
Gene expression in subcutaneous adipose tissue (SAT)
Gene expression assessed by RNA-Seq or qPCR analysis in SAT
Time frame: 2 weeks
Immune cell composition in PBMC and SAT
Immune cell composition measured using FACS analysis
Time frame: 2 weeks
Gut microbiome composition
Gut microbiome species as assessed by 16S rRNA gene sequencing of stool samples
Time frame: 2 weeks
Gut microbiome metabolites
Levels of microbiome-derived metabolites measured in stool samples
Time frame: 2 weeks
Mean glucose
Mean glucose level \[mg/dL\] measured using CGM
Time frame: 2 weeks
Glycemic variability
Intra- and inter-day glycemic fluctuation indices \[AU\] from CGM measurement
Time frame: 2 weeks
Time in range (TIR)
TIR \[%\] from CGM measurement
Time frame: 2 weeks
Glucose Management Indicator (GMI, estimated HbA1c)
GMI \[%\] from CGM measurement
Time frame: 2 weeks
Glucose Area Under the Curve (AUC) after a morning test meal
Glucose AUC \[mg/dL⋅min\] measured using CGM after a standardized morning test meal as an average of two test days within the observation period
Time frame: 3 and 10 days
Glucose AUC and iAUC after an evening test meal
Glucose AUC and iAUC \[mg/dL⋅min\] is measured using CGM after a standardized evening test meal as an average of two test days within the observation period
Time frame: 5 and 12 days
Eating timing and composition
Food type, quality, meal times and nutrient composition assessed by digital or paper-based food records
Time frame: 2 weeks
Physical activity
24-hour physical activity monitored by actigraphy
Time frame: 2 weeks
Sleep timing
Sleep timing (sleep onset and offset \[hh:mm\]) and sleep duration as monitored using a sleep diary and actigraphy
Time frame: 2 weeks
Objective sleep quality
Sleep quality as assessed by actigraphy
Time frame: 2 weeks
Light exposure
24-hour light exposure \[lux\] as monitored by actigraphy
Time frame: 2 weeks
Body temperature
24-hour body temperature \[°C\] will be monitored by actigraphy
Time frame: 2 weeks
Subjective sleep quality
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)
Time frame: 2 weeks
Chronotype
Chronotype assessed by the Munich Chronotype Questionnaire (MSFsc time, where later values correspond to later chronotype) and Morning-Eveningness Questionnaire (D-MEQ score, which ranges 19-76, where higher values correspond to later chronotype)
Time frame: 2 weeks
Body awareness
Body awareness assessed by the Multidimensional Assessment of Interoceptive Awareness (MAIA-2) and list of subjective hypoglycemia symptoms. The MAIA-2 provides subscale scores (across 8 dimensions) ranging from 1 to 5, where higher values correspond to greater interoceptive awareness and sensitivity to internal body signals
Time frame: 2 weeks
Eating Behavior
Eating behavior as assessed by the Dutch Eating Behavior Questionnaire (DEBQ). The DEBQ provides three distinct subscale scores-Emotional, External, and Controlled eating-each ranging from 1 to 4, where higher values correspond to greater prevalence of that specific eating behavior.
Time frame: 2 weeks
Emotional eating
Emotional eating behavior as assessed using the Salzburg Emotional Eating Scale (SEES). The SEES provides a score ranging from 1 to 5, where higher values correspond to greater frequency of emotional eating.
Time frame: 2 weeks
Food Timing
Food timing assessed using the Food Timing Screener (FTS) questionnaire, which provides timing of main meals and snacks \[hh:mm\]
Time frame: 2 weeks
Subjective feelings of hunger and satiety
Satiety and hunger scores assessed using Visual Analog Scales (VAS) before and after standardized test meals. VAS scores range from 0 to 100 mm, where higher values correspond to increased levels of hunger or fullness, respectively.
Time frame: 3, 5, 10 and 12 days
Health-related quality of life
Health-related quality-of-life, as assessed by the 36-Item Short Form Health Survey (SF-36), which provides standardized scores ranging from 0 to 100, where higher values correspond to better health-related quality of life
Time frame: 2 weeks
Affective states
Affective states as assessed with the Positive and Negative Affect Schedule (PANAS). The PANAS provides two subscale scores (Positive Affect and Negative Affect) ranging from 1 to 5, where higher values correspond to increased levels of positive or negative affect, respectively
Time frame: 2 weeks
Perceived stress
Perceived stress as assessed using the Perceived Stress Questionnaire (PSQ), which provides a score ranging from 0 to 40, where higher values correspond to greater levels of perceived stress
Time frame: 2 weeks
Anxiety
Anxiety levels as assessed using State-Trait Anxiety Inventory (STAI), which provides two subscale scores (State and Trait) ranging from 20 to 80, where higher values correspond to greater levels of state or trait anxiety, respectively
Time frame: 2 weeks
Depression
Depression levels as assessed using the Beck Depression Inventory (BDI) and the Health Questionnaire for Patients (PHQ-D). The BDI provides a score ranging from 0 to 63, where higher values correspond to greater severity of depressive symptoms. The PHQ-9 provides a score ranging from 0 to 27, where higher values correspond to greater severity of depressive symptoms.
Time frame: 2 weeks
Motivation
Motivation levels as assessed using the Behavioral Inhibition and Activation (BISBAS). The BIS/BAS provides three subscale scores (BIS, BAS-Reward Responsiveness, and BAS-Impulsivity) ranging from 8 to 32, where higher values correspond to greater sensitivity to threat or reward, respectively
Time frame: 2 weeks
Plan to share: No
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Start is estimated for Oct 2026; primary completion for Dec 2030, 50 months later.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Nutritional and Metabolic Diseases →
German Institute of Human Nutrition