Calorie RestrictionNCT05651620
The CALERIE™ Legacy Study
An observational study of Calorie Restriction, run by Tufts University at 3 sites in United States.
Trial summary
The purpose of the CALERIE Legacy Study is to follow up on the health and wellness of participants from phase 2 of the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) trial, which was conducted from 2007 to 2011. Read more about this study
- Who is it for?
- Ages 33 to 70 yearsHealthy volunteers can take part
- Conditions the study is for
- Calorie Restriction
- How many people
- 216 participants
- Where
- 3 sitesUnited States
- Study dates
- 6 Apr 2023to 31 Jan 2028
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 33 to 70 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: All CALERIE participants, except those who are deceased, are known not to qualify, or did not start their allocated group (CR intervention or ad libitum control) (n = 4), have been identified as potential subjects (n = 216) in the CALERIE Legacy Study. The demographic profile of this study is expected to be similar to that of the CALERIE trial, which was 70.4% female. Healthy individuals without obesity of either sex and all race and ethnic groups were eligible to participate in the CALERIE trial. However, due to safety concerns, pregnant women were excluded, and to avoid confounding from peri- and post-menopausal status, the upper age limit for women was 47 years. Upon enrollment, CALERIE participants were 21-50y, 77.3% White, 12% Black, and 10.7% other; ethnicity was 97% non-Hispanic.
Who may be able to join
- Enrolled in the CALERIE trial and started their allocated group (CR intervention or ad libitum control condition)
- Willing and able to attend one of the clinical sites for an in-person visit and provide informed consent
Who cannot join
- Pregnant women
- Women less than 12 months postpartum
- Documented note from the CALERIE trial indicating that the subject should not be contacted or requested not to be contacted for future research
- Diagnosed active cancer or terminal illness
Trial locations and contacts
3 sites in 1 country.
United States3 sites
Pennington Biomedical Research Center
Baton Rouge, Louisiana, 70808
Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University
Boston, Massachusetts, 02111
Washington University School of Medicine
St Louis, Missouri, 63110-1010
About this study
Official title: Legacy Effects of CALERIE™, a 2-year Calorie Restriction Intervention, on Hallmarks of Healthspan and Aging
The purpose of the CALERIE Legacy Study is to follow up on the health and wellness of participants from phase 2 of the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) trial, which was conducted from 2007 to 2011.
Read the detailed description
The CALERIE Legacy Study is an observational follow-up study of participants from phase 2 the CALERIE trial, the first randomized controlled trial of calorie restriction (CR) in humans without obesity. The overarching goal of the CALERIE Legacy Study is to examine whether two years of CR results in sustained improvements in the biological, phenotypic, and functional hallmarks of human aging 10 to 15 years after the structured intervention. Participants will complete clinical assessments, dietary recalls, and questionnaires, and laboratory evaluations will be performed on blood and urine samples. The study also includes an optional biospecimen banking component.
- Conditions
- Calorie Restriction
- Keywords
- calorie restriction, dietary intervention, biological aging, behavioral data
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Calorie Restriction (CR) | Individuals in the CR group were prescribed a 25% reduction from their baseline energy intake during the two-year CALERIE trial. | |
| Ad Libitum (AL) | Individuals in the AL group were asked to continue their usual dietary intake during the two-year CALERIE trial. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Biological age - Klemera-Doubal Method
Biological age will be quantified by the Klemera-Doubal Method (KDM), an algorithm-based measure. Biological age is expressed in years.
Measured: 11-16 years post CALERIE trial
Healthspan
Healthspan will be assessed by sex-specific metabolic syndrome z-score (MS z-score). MS z-score was developed using high density lipoprotein cholesterol (HDL), triglycerides (TG), waist circumference (WC), fasting blood glucose (FBG), and mean arterial pressure (MAP = [systolic blood pressure + 2 x diastolic blood pressure]/3). SDs for HDL and WC in the equations are sex specific.
Women: MS z-score = [45-HDL]/SDHDLW+ [TG-150]/SDTG + [WC-88]/SDWCW + [FBG-100]/SDFBG + [MAP -100]/SDMAP
Men: MS z-score = [40-HDL]/SDHDLM+ [TG-150]/SDTG + [WC-102]/SDWCM + [FBG-100]/SDFBG + [MAP -100]/SDMAP
W = women M = men
This score does not have a unit.
Measured: 11-16 years post CALERIE trial
Secondary outcomes (108)
Biological age - Homeostatic Dysregulation
Biological age will be quantified by homeostatic dysregulation, an algorithm-based measure. Biological age is expressed in years.
Measured: 11-16 years post CALERIE trial
Biological age - Levine Phenotypic Age
Biological age will be quantified by Levine Phenotypic Age, an algorithm-based measure. Biological age is expressed in years.
Measured: 11-16 years post CALERIE trial
Height
Height will be measured in cm.
Measured: 11-16 years post CALERIE trial
Weight
Weight will be measured in kg.
Measured: 11-16 years post CALERIE trial
Waist circumference
Weight circumference will be measured in cm.
Measured: 11-16 years post CALERIE trial
Hip circumference
Hip circumference will be measured in cm.
Measured: 11-16 years post CALERIE trial
Body mass index (BMI)
BMI (kg/m2) will be calculated using height and weight measurements.
Measured: 11-16 years post CALERIE trial
Blood pressure
Systolic and diastolic blood pressure will be measured in mmHg.
Measured: 11-16 years post CALERIE trial
Pulse rate at rest
Pulse rate will be measured in beats/min.
Measured: 11-16 years post CALERIE trial
Respiration rate at rest
Respiration rate will be measured in breaths/min.
Measured: 11-16 years post CALERIE trial
Fat mass
Whole-body fat mass (kg, %) as measured by dual-energy X-ray absorptiometry.
Measured: 11-16 years post CALERIE trial
Fat-free mass
Whole-body fat-free mass (kg, %) as measured by dual-energy X-ray absorptiometry.
Measured: 11-16 years post CALERIE trial
Bone mineral content
Whole-body bone mineral content (g) as measured by dual-energy X-ray absorptiometry.
Measured: 11-16 years post CALERIE trial
Resting metabolic rate (RMR)
RMR will be measured in kcal/d by indirect calorimetry using a ventilated hood system.
Measured: 11-16 years post CALERIE trial
Respiratory quotient (RQ)
RQ will be measured by indirect calorimetry using a ventilated hood system. This is a ratio (V̇CO2/V̇O2) and does not have a unit.
Measured: 11-16 years post CALERIE trial
Maximal aerobic capacity (V̇O2max)
Maximal aerobic capacity (V̇O2max) will be measured in mL/kg/min using the Cornell incremental treadmill test.
Measured: 11-16 years post CALERIE trial
Interleukin-6 (IL-6)
IL-6, a blood-based biomarker of aging proposed by the Targeting Aging with MEtformin (TAME) Biomarkers Workgroup, will be measured in pg/mL.
Measured: 11-16 years post CALERIE trial
Insulin - TAME panel
Insulin, a blood-based biomarker of aging proposed by the TAME Biomarkers Workgroup, will be measured in μIU/mL.
Measured: 11-16 years post CALERIE trial
Insulin - 0 min (OGTT)
Insulin (μIU/mL) will be measured at 0 minutes (pre-dose) during an oral glucose tolerance test (OGTT) to evaluate glucoregulatory response.
Measured: 11-16 years post CALERIE trial
Insulin - 30 min (OGTT)
Insulin (μIU/mL) will be measured at 30 minutes post dose during an OGTT to evaluate glucoregulatory response.
Measured: 11-16 years post CALERIE trial
Insulin - 60 min (OGTT)
Insulin (μIU/mL) will be measured at 60 minutes post dose during an OGTT to evaluate glucoregulatory response.
Measured: 11-16 years post CALERIE trial
Insulin - 90 min (OGTT)
Insulin (μIU/mL) will be measured at 90 minutes post dose during an OGTT to evaluate glucoregulatory response.
Measured: 11-16 years post CALERIE trial
Insulin - 120 min (OGTT)
Insulin (μIU/mL) will be measured at 120 minutes post dose during an OGTT to evaluate glucoregulatory response.
Measured: 11-16 years post CALERIE trial
Insulin-like growth factor 1 (IGF-1)
IGF-1, a blood-based biomarker of aging proposed by the TAME Biomarkers Workgroup, will be measured in ng/mL.
Measured: 11-16 years post CALERIE trial
Hemoglobin A1c (HbA1c)
HbA1c, a blood-based biomarker of aging proposed by the TAME Biomarkers Workgroup, will be measured in mmol/mol.
Measured: 11-16 years post CALERIE trial
Tumor necrosis factor α receptor II (TNFRII)
TNFRII, a blood-based biomarker of aging proposed by the TAME Biomarkers Workgroup, will be measured in ng/mL.
Measured: 11-16 years post CALERIE trial
High-sensitivity C-reactive protein (hsCRP)
hsCRP, a blood-based biomarker of inflammation, will be measured in μg/mL.
Measured: 11-16 years post CALERIE trial
Growth/differentiation factor 15 (GDF15)
GDF15, a blood-based biomarker of aging proposed by the TAME Biomarkers Workgroup, will be measured in pg/mL.
Measured: 11-16 years post CALERIE trial
Cystatin C
Cystatin C, a blood-based biomarker of aging proposed by the TAME Biomarkers Workgroup, will be measured in mg/L.
Measured: 11-16 years post CALERIE trial
N-terminal B-type natriuretic peptide (NT-proBNP)
NT-proBNP, a blood-based biomarker of aging proposed by the TAME Biomarkers Workgroup, will be measured in pg/mL.
Measured: 11-16 years post CALERIE trial
Senescence-associated secretory phenotype (SASP) proteins
SASP proteins, blood-based biomarkers of cellular senescence, will be measured using a SASP panel.
Measured: 11-16 years post CALERIE trial
Urinary Isoprostanes - iPF(2α)-III
Urinary iPF(2α)-III, a biomarker of systemic oxidative stress, will be measured in ng/mL.
Measured: 11-16 years post CALERIE trial
Urinary Isoprostanes - 2,3-dinor-iPF(2α)-III
Urinary 2,3-dinor-iPF(2α)-III, a biomarker of systemic oxidative stress, will be measured in ng/mL.
Measured: 11-16 years post CALERIE trial
Urinary Isoprostanes - iPF(2α)-VI
Urinary iPF(2α)-VI, a biomarker of systemic oxidative stress, will be measured in ng/mL.
Measured: 11-16 years post CALERIE trial
Urinary Isoprostanes - 8,12-iso-iPF(2α)-VI
Urinary 8,12-iso-iPF(2α)-VI, a biomarker of systemic oxidative stress, will be measured in ng/mL.
Measured: 11-16 years post CALERIE trial
Creatinine
Creatinine, a byproduct of routine activity in the muscle, will be measured in urine in mg/mL.
Measured: 11-16 years post CALERIE trial
Dehydroepiandrosterone (DHEA)
DHEA, a blood-based steroid hormone, will be measured in μg/dL.
Measured: 11-16 years post CALERIE trial
Interleukin 1 beta (IL-1b)
IL-1b, a blood-based marker of inflammation, will be measured in pg/mL.
Measured: 11-16 years post CALERIE trial
Interleukin 8 (IL-8)
IL-8, a blood-based marker of inflammation, will be measured in pg/mL.
Measured: 11-16 years post CALERIE trial
Tumor necrosis factor α (TNF-α)
TNF-α, a blood-based marker of inflammation, will be measured in pg/mL.
Measured: 11-16 years post CALERIE trial
Insulin-like growth factor-binding protein 1 (IGFBP-1)
IGFBP-1, a blood-based transport protein, will be measured in ng/mL.
Measured: 11-16 years post CALERIE trial
Transforming growth factor beta 1 (TGFB1)
TGFB1, a blood-based marker of immune function, will be measured in ng/mL.
Measured: 11-16 years post CALERIE trial
Insulin-like growth factor-binding protein 3 (IGFBP-3)
IGFBP-3, a blood-based transport protein, will be measured in ng/mL.
Measured: 11-16 years post CALERIE trial
Platelet-derived growth factor-AB (PDGF-AB)
PDGF-AB, a blood-based marker of cellular function, will be measured in ng/mL.
Measured: 11-16 years post CALERIE trial
Intercellular Adhesion Molecule 1 (ICAM-1)
ICAM-1, a blood-based marker of inflammation, will be measured in ng/mL.
Measured: 11-16 years post CALERIE trial
Growth hormone
Growth hormone, a blood-based bio-marker of cellular function, will be measured in ng/mL.
Measured: 11-16 years post CALERIE trial
Monocyte Chemoattractant Protein 1 (MCP1)
MCP1, a blood-based marker of inflammation, will be measured in pg/mL.
Measured: 11-16 years post CALERIE trial
Leptin
Leptin, a hormonal regulator of energy balance, will be measured in pg/mL.
Measured: 11-16 years post CALERIE trial
Total adiponectin
Total adiponectin, a protein hormone that regulates several metabolic processes, including glucose regulation and fatty acid oxidation, will be measured in μg/mL.
Measured: 11-16 years post CALERIE trial
High molecular weight adiponectin
High molecular weight adiponectin, a protein hormone that regulates several metabolic processes, including glucose regulation and fatty acid oxidation, will be measured in μg/mL.
Measured: 11-16 years post CALERIE trial
Muscle strength - Knee extension (60°)
Knee extension at 60 degrees per second will be measured by isokinetic dynamometry and expressed in Nm.
Measured: 11-16 years post CALERIE trial
Muscle strength - Knee extension (180°)
Knee extension at 180 degrees per second will be measured by isokinetic dynamometry and expressed in Nm.
Measured: 11-16 years post CALERIE trial
Muscle strength - Knee flexion (60°)
Knee flexion at 60 degrees per second will be measured by isokinetic dynamometry and expressed in Nm.
Measured: 11-16 years post CALERIE trial
Muscle strength - Knee flexion (180°)
Knee flexion at 180 degrees per second will be measured by isokinetic dynamometry and expressed in Nm.
Measured: 11-16 years post CALERIE trial
Handgrip Strength
Handgrip strength will be measured via a hand dynamometer and expressed in kg.
Measured: 11-16 years post CALERIE trial
Physical functioning
Physical functioning as measured by a physical performance battery. This physical performance battery provides a composite score ranging from 0 to 12 and includes results from the balance, gait and chair stand tests.
Measured: 11-16 years post CALERIE trial
Cognition
Cognition as measured by the Cambridge Neuropsychological Test Automated Battery (CANTAB). The CANTAB evaluates six main areas of cognitive function: reaction time; verbal recognition memory; intra-extra dimensional set shift; rapid visual information processing; delayed matching to sample; and spatial working memory.
Measured: 11-16 years post CALERIE trial
Dietary intake - calories
Dietary intake in calories (kcals/day), as measured by multiple-pass 24-hour dietary recalls and Nutrition Data System for Research (NDSR) software.
Measured: 11-16 years post CALERIE trial
Dietary intake - carbohydrates
Dietary carbohydrates (grams and % of energy intake) will be measured by multiple-pass 24-hour dietary recalls and Nutrition Data System for Research (NDSR) software.
Measured: 11-16 years post CALERIE trial
Dietary intake - proteins
Dietary proteins (grams and % of energy intake) will be measured by multiple-pass 24-hour dietary recalls and Nutrition Data System for Research (NDSR) software.
Measured: 11-16 years post CALERIE trial
Health-related quality of life
Quality of life as measured by the RAND 36-Item Short Form Survey (SF-36). The RAND SF-36 measures eight aspects of health: physical functioning, role limitations due to physical health problems, role limitations due to personal or emotional problems, energy/fatigue, emotional well-being, social functioning, bodily pain, and general health perceptions. It also includes a single item that provides an indication of perceived change in health. Each item is on a 3- or 5-point Likert scale (1-3 or 1-5). Each response is transformed to a recoded value of 0-100, and the transformed scores of the 9 subscales are averaged to derive a composite score. Higher scores indicate more favorable health states.
Measured: 11-16 years post CALERIE trial
Depression status
Depression status as measured by the Beck Depression Inventory II (BDI-II). The 21-item BDI-II measures depression severity. The score range is 0-63, with higher scores indicating greater depression severity. Nineteen items are on a 4-point Likert scale (0-3). Two items are on a 7-point Likert scale, and responses are scaled to 0-3. The values are summed to calculate the total score.
Measured: 11-16 years post CALERIE trial
Mood
Mood as measured by the Profile of Mood States Second Edition (POMS 2). The POMS 2 assesses six mood subscales using 65 items, each on a 5-point Likert scale (0-4): tension-anxiety (9 items, score range 0-36), depression-dejection (15 items, range 0-60), anger-hostility (12 items, range 0-48), vigor-activity (8 items, range 0-32), fatigue-inertia (7 items, range 0-28), and confusion-bewilderment (7 items, range 0-28). High vigor-activity scores reflect a good mood or emotion, and low scores in the other subscales reflect a good mood or emotion. Total mood disturbance, which is calculated by subtracting the vigor subscale score from the total subscale score (range 0-200), also will be assessed.
Measured: 11-16 years post CALERIE trial
Sleep
Sleep as measured by the Pittsburgh Sleep Quality Index (PSQI). The PSQI measures sleep quality and disturbance over the course of one month using seven subscales: subjective sleep quality; sleep latency; sleep duration; habitual sleep efficiency; sleep disturbances; use of sleeping medication; and daytime dysfunction. The scoring range of each subscale is 0-3. The scoring range of the Global PSQI (the composite score of the seven subscales) is 0-21. For both the subscales and Global PSQI, higher scores indicate greater difficulties with sleeping.
Measured: 11-16 years post CALERIE trial
Sexual function
Sexual function as measured by the Derogatis Interview for Sexual Functioning - Self Report (DISF-SR). Both versions of the DISF-SR (male and female) are scored from 20 to 75, with higher scores indicating higher sexual functioning.
Measured: 11-16 years post CALERIE trial
Food cravings
Food cravings as measured by the Food Cravings Questionnaire-Trait (FCQ-T). The FCQ-T measures frequency and intensity of food cravings. It has 39 items on a 6-point Likert scale (1-6) and a score range of 39-234. Higher scores indicate more frequent and intense food cravings. Scores on all items are summed for a total score.
Measured: 11-16 years post CALERIE trial
Dietary restraint, disinhibition, and hunger
Dietary restraint, disinhibition, and hunger as measured by the Three-Factor Eating Questionnaire (TFEQ). The 51-item TFEQ will be used to measure dietary restraint (21 items), disinhibition (16 items), and hunger (14 items). Item responses are scored as 0 or 1 and summed. Higher scores indicate higher levels of restrained eating (range 0-21), disinhibited eating (range 0-16), and predisposition to hunger (range 0-14).
Measured: 11-16 years post CALERIE trial
Disordered eating
Disordered eating as measured by the Multiaxial Assessment of Eating Disorder Symptoms (MAEDS). MAEDS will be used to assess six domains of disordered eating: binge eating (range 8-56), restrictive eating (range 9-63), purgative behavior (range 7-49), fear of fatness (range 11-77), avoidance of forbidden foods (range 10-70), and depression (range 11-77).
Measured: 11-16 years post CALERIE trial
Body shape perceptions
Body shape perceptions as measured by the Body Shape Questionnaire (BSQ). Items on the BSQ are rated on a 6-point Likert-type scale. The score ranges from 34-204 points. Higher scores indicate increased concern regarding body shape.
Measured: 11-16 years post CALERIE trial
Physical activity
Physical activity as measured by the 7-Day Stanford Physical Activity Recall (PAR). The PAR estimates an individual's time spent in sleep and physical activity for the 7 days prior to the interview. Energy expenditure based on time spent in sleep and physical activities can be estimated. Sub-scores of energy expenditure for each of the following activities are calculated, summed, and averaged to estimate energy expenditure as kilocalories per day: sleep, moderate physical activity, hard physical activity, and very hard physical activity. Higher scores indicate greater physical activity per day. Metabolic equivalent (MET) value for each activity is provided: 1 MET for sleep, 4 METs for moderate activity, 6 METs for hard activity, and 10 METs for very hard activity. Time spent in each activity over 7 days is multiplied by the appropriate MET value. The minimum value for each activity is zero; there is no maximum value.
Measured: 11-16 years post CALERIE trial
Resilience
Resilience as measured by the 25-item Connor-Davidson Resilience Scale (CD-RISC-25). CD-RISC-25 is scored from 0 to 100, with higher scores indicating higher resilience.
Measured: 11-16 years post CALERIE trial
Total cholesterol
Total cholesterol will be measured in mg/dL using a standard lipid panel.
Measured: 11-16 years post CALERIE trial
High-density lipoprotein cholesterol (HDL-C)
HDL-C will be measured in mg/dL using a standard lipid panel.
Measured: 11-16 years post CALERIE trial
Triglycerides
Triglycerides will be measured in mg/dL using a standard lipid panel.
Measured: 11-16 years post CALERIE trial
Low-density lipoprotein cholesterol (LDL-C)
LDL-C will be calculated in mg/dL using measured values of total cholesterol, HDL-C, and triglycerides.
Measured: 11-16 years post CALERIE trial
Glucose - 0 min (OGTT)
Glucose (mg/dL) will be measured at 0 minutes (pre-dose) during an OGTT to evaluate glucoregulatory response.
Measured: 11-16 years post CALERIE trial
Glucose - 30 min (OGTT)
Glucose (mg/dL) will be measured at 30 minutes post dose during an OGTT to evaluate glucoregulatory response.
Measured: 11-16 years post CALERIE trial
Glucose - 60 min (OGTT)
Glucose (mg/dL) will be measured at 60 minutes post dose during an OGTT to evaluate glucoregulatory response.
Measured: 11-16 years post CALERIE trial
Glucose - 90 min (OGTT)
Glucose (mg/dL) will be measured at 90 minutes post dose during an OGTT to evaluate glucoregulatory response.
Measured: 11-16 years post CALERIE trial
Glucose - 120 min (OGTT)
Glucose (mg/dL) will be measured at 120 minutes post dose during an OGTT to evaluate glucoregulatory response.
Measured: 11-16 years post CALERIE trial
Insulin resistance
Insulin resistance will be calculated using the Homeostatic Model Assessment (HOMA) and measured values of fasting glucose (mmol/L) and fasting insulin (μ/L): (fasting glucose × fasting insulin) ∕ 22.5
Measured: 11-16 years post CALERIE trial
Beta-cell function
Beta-cell function will be calculated using HOMA-β and measures of fasting insulin (μ/L) and fasting glucose (mg/dL): HOMA-β (%) = (360 × fasting insulin) ∕ (fasting glucose - 63)
Measured: 11-16 years post CALERIE trial
Insulinogenic Index
Insulinogenic index will be calculated as the ratio of change in plasma insulin (I) from 0 to 30 min of the OGTT to the change in plasma glucose (G) over the same period (∆I0-30 min ∕ ∆G0-30 min).
Measured: 11-16 years post CALERIE trial
Insulin Sensitivity Index (ISI)
Insulin sensitivity index will be calculated as 1 ∕ fasting insulin (μ/L).
Measured: 11-16 years post CALERIE trial
Oral Disposition Index
The Oral Disposition Index will be calculated as the product of insulinogenic index and insulin sensitivity index.
Measured: 11-16 years post CALERIE trial
Triiodothyronine (T3)
T3, a blood-based marker of thyroid function, will be measured in ng/dL.
Measured: 11-16 years post CALERIE trial
Thyroxine (T4)
T4, a blood-based marker of thyroid function, will be measured in ng/dL.
Measured: 11-16 years post CALERIE trial
Thyroid stimulating hormone (TSH)
TSH, a blood-based marker of thyroid function, will be measured in μIU/mL.
Measured: 11-16 years post CALERIE trial
Alkaline phosphatase (ALKP)
ALKP, a blood-based marker of liver function, will be measured in IU/L.
Measured: 11-16 years post CALERIE trial
Alanine transaminase (ALT)
ALT, a blood-based marker of liver function, will be measured in U/L.
Measured: 11-16 years post CALERIE trial
Aspartate aminotransferase (AST)
AST, a blood-based marker of liver function, will be measured in U/L.
Measured: 11-16 years post CALERIE trial
Albumin
Albumin, a blood-based marker of liver and kidney function, will be measured in g/dL.
Measured: 11-16 years post CALERIE trial
Blood Urea Nitrogen (BUN)
BUN, a blood-based marker of kidney function, will be measured in mg/dL.
Measured: 11-16 years post CALERIE trial
Total Proteins
Total proteins are computed as a sum of albumin and globulin. Total proteins are indicative of blood vessel and immune system function and will be measured in g/dL.
Measured: 11-16 years post CALERIE trial
Bilirubin
Bilirubin, a blood-based marker of liver function, will be measured in mg/dL.
Measured: 11-16 years post CALERIE trial
Creatine Phosphokinase (CPK)
CPK, an enzyme marker of energy homeostasis, will be measured in U/L.
Measured: 11-16 years post CALERIE trial
Lactate Dehydrogenase (LDH)
LDH, an enzyme marker of liver function, will be measured in U/L.
Measured: 11-16 years post CALERIE trial
Globulin
Globulin, a blood-based marker of liver function, will be measured in g/dL.
Measured: 11-16 years post CALERIE trial
Albumin/Globulin (A/G) ratio
A/G ratio is a blood-based marker used to monitor nutritional status and immune system, kidney, and liver function. This marker is a ratio, and therefore does not have units.
Measured: 11-16 years post CALERIE trial
Uric Acid
Uric acid, a blood-based marker of purine metabolism, will be measured in mg/dL.
Measured: 11-16 years post CALERIE trial
Calcium (Ca)
Calcium, a blood-based mineral, will be measured in mg/dL.
Measured: 11-16 years post CALERIE trial
Phosphorus (P)
Phosphorus, a blood-based mineral, will be measured in mg/dL.
Measured: 11-16 years post CALERIE trial
Magnesium (Mg)
Magnesium, a blood-based mineral, will be measured in meq/L.
Measured: 11-16 years post CALERIE trial
Sodium (Na+)
Sodium, an electrolyte that reflects the body's fluid balance, will be measured in meq/L.
Measured: 11-16 years post CALERIE trial
Potassium (K+)
Potassium, an electrolyte that reflects the body's fluid balance, will be measured in meq/L.
Measured: 11-16 years post CALERIE trial
Chloride (Cl-)
Chloride, an electrolyte that reflects the body's fluid balance, will be measured in meq/L.
Measured: 11-16 years post CALERIE trial
Apoprotein A1
Apoprotein A1, a blood-based marker of lipid metabolism, will be measured in mg/dL.
Measured: 11-16 years post CALERIE trial
Apoprotein B
Apoprotein B, a blood-based marker of lipid metabolism, will be measured in mg/dL.
Measured: 11-16 years post CALERIE trial
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Dec 2022
- Study start6 Apr 2023
- Primary completion31 Jan 2027 (estimated)
- Study completion31 Jan 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Calorie RestrictionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Other
- Enrolment
- 216 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Tufts University
- Sponsor type
- University, hospital or other
- Collaborators
- Pennington Biomedical Research Center, Washington University School of Medicine, Duke University, National Institute on Aging (NIA)
- Responsible party
- Principal investigator, Sai Krupa Das, Tufts University
- Investigators
- Sai Krupa Das, PhD, Principal investigator, Tufts University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05651620
- Sponsor's protocol ID
- STUDY00002577
- Other IDs
- 1R01AG071717-01A1
- Status last verified
- Jun 2026
- First submitted
- 1 Sep 2022
- Last updated
- 9 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Per the NIH Data Public Access Policy, after study closure, the data coordinating center at Duke University will lock the electronic database and clean and deidentify the data prior to public posting. Biospecimens collected for banking will be deidentified and transferred to the NIA AgingResearchBiobank, which utilizes a state-of-the-art inventory system for the storage and distribution of study samples for future scientific research. The study protocol and informed consent form will be made available as well.
Study at a glance
From the registry record, last updated by the sponsor on 9 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Legacy Effects of CALERIE™, a 2-year Calorie Restriction Intervention, on Hallmarks of Healthspan and Aging
- ClinicalTrials.gov ID
- NCT05651620
- Acronym / sponsor ID
- STUDY00002577
- Conditions
- Calorie Restriction
- Keywords
- calorie restriction, dietary intervention, biological aging, behavioral data
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 216 participants (estimated)
- Lead sponsor
- Tufts UniversityUniversity, hospital or other
- Collaborators
- Pennington Biomedical Research Center, Washington University School of Medicine, Duke University, National Institute on Aging (NIA)
- Study start
- 6 Apr 2023 (actual)
- Primary completion
- 31 Jan 2027 (estimated)
- Study completion
- 31 Jan 2028 (estimated)
- First posted
- 15 Dec 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of the CALERIE Legacy Study is to follow up on the health and wellness of participants from phase 2 of the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) trial, which was conducted from 2007 to 2011.
Detailed description
The CALERIE Legacy Study is an observational follow-up study of participants from phase 2 the CALERIE trial, the first randomized controlled trial of calorie restriction (CR) in humans without obesity. The overarching goal of the CALERIE Legacy Study is to examine whether two years of CR results in sustained improvements in the biological, phenotypic, and functional hallmarks of human aging 10 to 15 years after the structured intervention. Participants will complete clinical assessments, dietary recalls, and questionnaires, and laboratory evaluations will be performed on blood and urine samples. The study also includes an optional biospecimen banking component.
Study design
- Observational model
- Case-control
- Time perspective
- Other
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Calorie Restriction (CR) | – | –Individuals in the CR group were prescribed a 25% reduction from their baseline energy intake during the two-year CALERIE trial. |
| Ad Libitum (AL) | – | –Individuals in the AL group were asked to continue their usual dietary intake during the two-year CALERIE trial. |
Who may qualify
- Ages
- 33 to 70 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- All CALERIE participants, except those who are deceased, are known not to qualify, or did not start their allocated group (CR intervention or ad libitum control) (n = 4), have been identified as potential subjects (n = 216) in the CALERIE Legacy Study. The demographic profile of this study is expected to be similar to that of the CALERIE trial, which was 70.4% female. Healthy individuals without obesity of either sex and all race and ethnic groups were eligible to participate in the CALERIE trial. However, due to safety concerns, pregnant women were excluded, and to avoid confounding from peri- and post-menopausal status, the upper age limit for women was 47 years. Upon enrollment, CALERIE participants were 21-50y, 77.3% White, 12% Black, and 10.7% other; ethnicity was 97% non-Hispanic.
Key inclusion criteria (2 listed)
- Enrolled in the CALERIE trial and started their allocated group (CR intervention or ad libitum control condition)
- Willing and able to attend one of the clinical sites for an in-person visit and provide informed consent
Key exclusion criteria (4 listed)
- Pregnant women
- Women less than 12 months postpartum
- Documented note from the CALERIE trial indicating that the subject should not be contacted or requested not to be contacted for future research
- Diagnosed active cancer or terminal illness
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Biological age - Klemera-Doubal Method
Time frame: 11-16 years post CALERIE trial
Biological age will be quantified by the Klemera-Doubal Method (KDM), an algorithm-based measure. Biological age is expressed in years.
Healthspan
Time frame: 11-16 years post CALERIE trial
Healthspan will be assessed by sex-specific metabolic syndrome z-score (MS z-score). MS z-score was developed using high density lipoprotein cholesterol (HDL), triglycerides (TG), waist circumference (WC), fasting blood glucose (FBG), and mean arterial pressure (MAP = [systolic blood pressure + 2 x diastolic blood pressure]/3). SDs for HDL and WC in the equations are sex specific. Women: MS z-score = [45-HDL]/SDHDLW+ [TG-150]/SDTG + [WC-88]/SDWCW + [FBG-100]/SDFBG + [MAP -100]/SDMAP Men: MS z-score = [40-HDL]/SDHDLM+ [TG-150]/SDTG + [WC-102]/SDWCM + [FBG-100]/SDFBG + [MAP -100]/SDMAP W = women M = men This score does not have a unit.
108 secondary outcomes
Biological age - Homeostatic Dysregulation
Time frame: 11-16 years post CALERIE trial
Biological age - Levine Phenotypic Age
Time frame: 11-16 years post CALERIE trial
Height
Time frame: 11-16 years post CALERIE trial
Weight
Time frame: 11-16 years post CALERIE trial
Waist circumference
Time frame: 11-16 years post CALERIE trial
Hip circumference
Time frame: 11-16 years post CALERIE trial
Body mass index (BMI)
Time frame: 11-16 years post CALERIE trial
Blood pressure
Time frame: 11-16 years post CALERIE trial
Pulse rate at rest
Time frame: 11-16 years post CALERIE trial
Respiration rate at rest
Time frame: 11-16 years post CALERIE trial
Fat mass
Time frame: 11-16 years post CALERIE trial
Fat-free mass
Time frame: 11-16 years post CALERIE trial
Bone mineral content
Time frame: 11-16 years post CALERIE trial
Resting metabolic rate (RMR)
Time frame: 11-16 years post CALERIE trial
Respiratory quotient (RQ)
Time frame: 11-16 years post CALERIE trial
Maximal aerobic capacity (V̇O2max)
Time frame: 11-16 years post CALERIE trial
Interleukin-6 (IL-6)
Time frame: 11-16 years post CALERIE trial
Insulin - TAME panel
Time frame: 11-16 years post CALERIE trial
Insulin - 0 min (OGTT)
Time frame: 11-16 years post CALERIE trial
Insulin - 30 min (OGTT)
Time frame: 11-16 years post CALERIE trial
Insulin - 60 min (OGTT)
Time frame: 11-16 years post CALERIE trial
Insulin - 90 min (OGTT)
Time frame: 11-16 years post CALERIE trial
Insulin - 120 min (OGTT)
Time frame: 11-16 years post CALERIE trial
Insulin-like growth factor 1 (IGF-1)
Time frame: 11-16 years post CALERIE trial
Hemoglobin A1c (HbA1c)
Time frame: 11-16 years post CALERIE trial
Tumor necrosis factor α receptor II (TNFRII)
Time frame: 11-16 years post CALERIE trial
High-sensitivity C-reactive protein (hsCRP)
Time frame: 11-16 years post CALERIE trial
Growth/differentiation factor 15 (GDF15)
Time frame: 11-16 years post CALERIE trial
Cystatin C
Time frame: 11-16 years post CALERIE trial
N-terminal B-type natriuretic peptide (NT-proBNP)
Time frame: 11-16 years post CALERIE trial
Senescence-associated secretory phenotype (SASP) proteins
Time frame: 11-16 years post CALERIE trial
Urinary Isoprostanes - iPF(2α)-III
Time frame: 11-16 years post CALERIE trial
Urinary Isoprostanes - 2,3-dinor-iPF(2α)-III
Time frame: 11-16 years post CALERIE trial
Urinary Isoprostanes - iPF(2α)-VI
Time frame: 11-16 years post CALERIE trial
Urinary Isoprostanes - 8,12-iso-iPF(2α)-VI
Time frame: 11-16 years post CALERIE trial
Creatinine
Time frame: 11-16 years post CALERIE trial
Dehydroepiandrosterone (DHEA)
Time frame: 11-16 years post CALERIE trial
Interleukin 1 beta (IL-1b)
Time frame: 11-16 years post CALERIE trial
Interleukin 8 (IL-8)
Time frame: 11-16 years post CALERIE trial
Tumor necrosis factor α (TNF-α)
Time frame: 11-16 years post CALERIE trial
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Jun 2026.
- Individual participant dataSharing planned: Yes. Per the NIH Data Public Access Policy, after study closure, the data coordinating center at Duke University will lock the electronic database and clean and deidentify the data prior to public posting. Biospecimens collected for banking will be deidentified and transferred to the NIA AgingResearchBiobank, which utilizes a state-of-the-art inventory system for the storage and distribution of study samples for future scientific research. The study protocol and informed consent form will be made available as well.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Sai Krupa Das, PhD principal investigator
Tufts University
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Calorie Restriction, run by Tufts University at 3 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 9 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Biological age - Klemera-Doubal Method (time frame: 11-16 years post CALERIE trial). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Jun 2026.