An interventional study of Mediterranean-style diet with potatoes and Traditional-style Mediterranean diet in Prediabetes, sponsored by Penn State University. Recruiting at 1 site in United States. Open to participants aged 25 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-10-05.
Sponsored by Penn State University · Not applicable, Interventional, and Prevention
The purpose of this research study is to determine if a healthy Mediterranean diet containing one medium potato/day has equivalent or non-different effects on risk factors for type 2 diabetes and heart disease compared to a healthy Mediterranean diet without potatoes in adults with prediabetes. Participants will be randomly assigned to one of the test diets and be asked to consume this diet for 12 weeks (84 days). Testing will be conducted at the beginning and end of the study.
This is a 12-week, 2-arm parallel, randomized controlled feeding trial. Participants will be randomized to either a Mediterranean-style diet that includes 1 medium potato/day/2000 kcal replacing some grains , or a traditional-style Mediterranean dietary pattern without potatoes. All food will be provided for the 12-week study duration.
999 studies on the registry are indexed under Prediabetic State; 238 are open to participants now.
This study's planned enrollment of 74 is above the median of 65 across 844 interventional studies indexed under Prediabetic State.
Browse Prediabetic State studies →Penn State University is the lead sponsor of 263 studies on the registry; 51 are open to participants now.
Of its 13 completed or terminated interventional studies of FDA-regulated products, 10 (77%) have results posted.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Fasting triglycerides >350 mg/dL at screening
-≥10% change in body weight within the 6 months prior to enrollment
Mediterranean-style diet that includes 1 medium potato/day/2000 kcal replacing some grains
Other: Mediterranean-style diet with potatoes
A traditional-style Mediterranean diet that does not contain potatoes (potatoes are not a defining feature of this diet) and is higher in grains.
Other: Traditional-style Mediterranean diet
The diet will contain 1 medium potato/day/2000 kcal
Traditional-style Mediterranean diet higher in grains
Change in HbA1c
HbA1c will be assessed at baseline and 12-weeks and expressed as percentage . The change in HbA1c will be calculated by subtracting the baseline value from the 12 week value and expressed as percentage point change.
Time frame: 12-weeks
Change in fasting glucose
Change in fasting plasma glucose expressed as mg/dL. Change in glucose will be calculated as the mean of the 12 week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
Time frame: 12-weeks
Change in mean glucose
Change in mean glucose assessed by a continuous glucose monitor (CGM) expressed as mg/dL. Change in mean glucose will be calculated as mean glucose assessed from 7 days of CGM wear at 12 weeks minus mean glucose assessed from 7 days of CGM wear at baseline.
Time frame: 12-weeks
Change in mean time in range
Change in mean time in range (glucose 70-140 mg/dL) assessed by a continuous glucose monitor (CGM) expressed as minutes per day. Change in mean time in range will be calculated as mean time in range assessed from 7 days of CGM wear at 12 weeks minus mean time in range assessed from 7 days of CGM wear at baseline.
Time frame: 12-weeks
Change in glycemic variability
Change in mean glycemic variability assessed by a continuous glucose monitor (CGM) expressed as the coefficient of variability. Change in mean glycemic variability will be calculated as mean glycemic variability assessed from 7 days of CGM wear at 12 weeks minus mean glycemic variability assessed from 7 days of CGM wear at baseline.
Time frame: 12-weeks
Change in fasting insulin
Change in fasting serum insulin expressed as micro IU/mL. Change in insulin will be calculated as the mean of the 12 week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
Time frame: 12-weeks
Change in homeostatic model of insulin resistance (HOMA-IR)
Homeostatic model of insulin resistance (HOMA-IR) will be calculated from insulin and glucose measured from a fasting blood sample. Calculated as (insulin × glucose) / 22.5. Change in HOMA-IR will be calculated as the mean of the 12 week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
Time frame: 12-weeks
Change in LDL-Cholesterol
Assessed from fasting blood draw expressed in mg/dL. Change in LDL-cholesterol will be calculated as the mean of the 12-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
Time frame: 12-weeks
Change in apolipoprotein B
Assessed from fasting blood draw expressed in mg/dL. Change in apolipoprotein B will be calculated by subtracting the baseline value from the 12 week value.
Time frame: 12-weeks
Change in non-HDL cholesterol
Assessed from fasting blood draw expressed in mg/dL. Change in non-HDL cholesterol will be calculated as the mean of the 12-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
Time frame: 12-weeks
Change in Total Cholesterol
Assessed from fasting blood draw expressed in mg/dL. Change in total cholesterol will be calculated as the mean of the 12-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
Time frame: 12-weeks
Change in HDL-Cholesterol
Assessed from fasting blood draw expressed in mg/dL. Change in HDL-cholesterol will be calculated as the mean of the 12-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
Time frame: 12-weeks
Change in Triglycerides
Assessed from fasting blood draw expressed in mg/dL. Change in triglycerides will be calculated as the mean of the 12-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
Time frame: 12-weeks
Change in C-reactive protein
Assessed from fasting blood draw expressed in mg/L. Change in C-reactive protein will be calculated as the mean of the 12-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
Time frame: 12-weeks
Change in Central Systolic and Diastolic Blood Pressure
Central blood pressure measured assessed using a SphymoCor Xcel (Atcor Medical) at baseline \& 12 weeks. Change will be calculated by subtracting the baseline value from the end point value.
Time frame: 12-weeks
Change in Peripheral Systolic and Diastolic Blood Pressure
Peripheral blood pressure measured assessed using a SphymoCor Xcel (Atcor Medical) at baseline \& 12 weeks. Change will be calculated by subtracting the baseline value from the end point value.
Time frame: 12-weeks
Change in Carotid-Femoral Pulse Wave Velocity
Measured assessed using a SphymoCor Xcel (Atcor Medical) at baseline \& 12 weeks. Change will be calculated by subtracting the baseline value from the end point value.
Time frame: 12-weeks
Change in particle size and number of LDL, HDL, triglyceride rich lipoproteins
Measured via Nuclear Magnetic Resonance
Time frame: 12-weeks
Diet Satisfaction
Participants will complete a survey that we have previously developed to assess diet satisfaction at 12 weeks.
Time frame: 12-weeks
Documents are hosted by the registry — open the source record to download them.
Plan to share: Yes
Supporting information: Study protocol, Sap
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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