An interventional study of Standard NDPP and Very low-carbohydrate diet in PreDiabetes, sponsored by University of Michigan. Completed at 1 site in United States. Open to participants aged 21 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-10-06.
Sponsored by University of Michigan · Not applicable, Interventional, and Treatment
This research tested whether a standard version or very low-carbohydrate version of the Diabetes Prevention Program better improves outcomes like blood glucose control and body weight for patients with prediabetes.
Participants had screening (included blood draw) and baseline testing with a continuous glucose monitor. Once these enrollment steps were completed, the participants were randomized to one of two groups: a standard National Diabetes Prevention Program (NDPP) or a very low-carbohydrate version.
In addition to following the diet for 12 months, participants were asked to participate in hour-long weekly group classes over Zoom. After four months in the program, classes occurred about every month to help participants maintain the new diet. There were also check-ins and follow-up visits throughout the study.
999 studies on the registry are indexed under Prediabetic State; 238 are open to participants now.
This study's enrollment of 304 is above the median of 65 across 844 interventional studies indexed under Prediabetic State.
Browse Prediabetic State studies →University of Michigan is the lead sponsor of 1,475 studies on the registry; 196 are open to participants now.
Of its 162 completed or terminated interventional studies of FDA-regulated products, 128 (79%) have results posted.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Primary
Ability
Safety
any concerning values in baseline labs (participants will be referred to PCP and will be allowed to return for later enrollment if labs are no longer concerning):
12-month long, calorie-restricted NDPP
Behavioral: Standard NDPP
The VLCD was an adaptation of the standard NDPP curriculum, which preserved all features with the exception of altered dietary advice.
Behavioral: Very low-carbohydrate diet
Participants in this arm were taught to manage their prediabetes with the Centers for Disease Control's standard National Diabetes Prevention Program (NDPP). The NDPP teaches a lower calorie, lower fat diet. There was a core phase and a maintenance phase of this study; the core phase lasted for about 4 months and involved weekly or every other week classes, home assignments, and brief check-in surveys. The maintenance phase lasted for the remaining time, with classes and check-in surveys approximately once a month.
Participants in this arm were taught to manage their prediabetes with the Centers for Disease Control's National Diabetes Prevention Program, adapted to teach a very low-carbohydrate diet, also called a ketogenic or "keto" diet. This diet involved eating non-starchy vegetables, leafy greens, cheese, meats, berries, nuts, and seeds, and avoiding starchy foods like pasta, bread, rice, beans, and many fruits. There was a core phase and a maintenance phase of this study; the core phase lasted for about 4 months and involved weekly or every other week classes, home assignments, and brief check-in surveys. The maintenance phase lasted for the remaining time, with classes and check-in surveys approximately once a month.
Change in HbA1c
HbA1c is the proportion of hemoglobin in the blood that has glucose attached to it relative to total hemoglobin. It reflects average blood glucose levels over approximately the previous 2-3 months. To assess the effect of dietary intervention on HbA1c, the change in HbA1c from baseline to 12 months was compared between the two diet groups. A negative change indicates an improvement in HbA1c from baseline.
Time frame: Baseline, 12 months
Change in Inflammation based on C-reactive protein (CRP)
High-sensitivity C-reactive protein (hsCRP) was measured quantitatively in serum using a latex immunoturbidimetric assay. Levels of hsCRP are considered a measure of systemic inflammation, with higher levels indicating more inflammation. To assess the effect of dietary intervention on hsCRP, the change in hsCRP from baseline to 12 months was compared between the two diet groups. A negative change indicates a decrease in hsCRP from baseline.
Time frame: Baseline, 12 months
Change in percent body weight
Percentage change in body weight. Body weight data were collected using at-home scales. Percentage change in body weight from baseline to 12 months was calculated as the difference between body weight at 12 months and baseline, divided by baseline body weight and multiplied by 100. A negative percentage change indicates a decrease in body weight from baseline. The percentage change in body weight was compared between the two diet groups.
Time frame: Baseline, 12 months
Change in glycemic variability (SD)
Glucose levels were measured using an Abbott Libre Pro continuous glucose monitoring device that was worn on the participant's upper arm, with glucose data masked to participants. The monitoring device recorded glucose levels in the interstitial fluid using a glucose oxidase method every 15 minutes, continuously for 14 days at each timepoint. Glucose variability was calculated as the standard deviation (SD) of glucose from the continuous glucose monitoring data. The change in glucose variability (SD) from baseline to 12 months was compared between the two diet groups. A negative change indicates a decrease in glucose variability from baseline.
Time frame: Baseline, 12 months
Change in glycemic variability (coefficient of variation)
Glucose levels were measured using an Abbott Libre Pro continuous glucose monitoring device that was worn on the participant's upper arm, with glucose data masked to participants. The monitoring device recorded glucose levels in the interstitial fluid using a glucose oxidase method every 15 minutes, continuously for 14 days at each timepoint. Glucose variability was calculated as the coefficient of variation (CV), defined as the SD of glucose divided by mean glucose × 100%, from the continuous glucose monitoring data. The change in glucose variability (CV) from baseline to 12 months was compared between the two diet groups. A negative change indicates a decrease in glucose variability from baseline.
Time frame: Baseline, 12 months
Change in the proportion of time in very tight range
Glucose levels were measured using an Abbott Libre Pro continuous glucose monitoring device that was worn on the participant's upper arm, with glucose data masked to participants. The monitoring device recorded participants' glucose levels in the interstitial fluid using a glucose oxidase method every 15 minutes, continuously for 14 days at each timepoint. The proportion of time in very tight range (70-120 mg/dL) was calculated. The change in the proportion of time in tight range from baseline to 12 months was compared between the two diet groups. A positive change indicates an increase in the proportion of time in very tight range from baseline.
Time frame: Baseline, 12 months
Change in the proportion of time above range
Glucose levels were measured using an Abbott Libre Pro continuous glucose monitoring device that was worn on the participant's upper arm, with glucose data masked to participants. The device recorded glucose levels in the interstitial fluid using a glucose oxidase method every 15 minutes, continuously for 14 days at each time point. The proportion of time above range (glucose \>140 mg/dL for at least 15 minutes) was calculated. The change in the proportion of time above range from baseline to 12 months was compared between the two diet groups. A negative change indicates a decrease in the proportion of time above range from baseline.
Time frame: Baseline, 12 months
Change in small particle low-density lipoproteins (LDL)
Small LDL particle concentration (small LDL-P) was measured using nuclear magnetic resonance (NMR) spectroscopy. Higher concentrations of small LDL-P have been associated with increased cardiovascular risk. To assess the effect of dietary intervention on small LDL-P, the change in small LDL-P from baseline to 12 months was compared between the two diet groups. A negative change indicates a decrease in small LDL-P from baseline.
Time frame: Baseline, 12 months
Change in high-density lipoproteins (HDL)
HDL cholesterol levels were measured using nuclear magnetic resonance (NMR) spectroscopy. Lower HDL levels have been associated with increased cardiovascular risk. To assess the effect of dietary intervention on HDL, the change in HDL from baseline to 12 months was compared between the two diet groups. A positive change indicates an increase in HDL from baseline.
Time frame: Baseline, 12 months
Change in triglycerides
Triglyceride levels were measured using nuclear magnetic resonance (NMR) spectroscopy. Higher concentrations of triglycerides have been associated with increased cardiovascular risk. To assess the effect of dietary intervention on triglycerides, the change in triglycerides from baseline to 12 months was compared between the two diet groups. A negative change indicates a decrease in triglycerides from baseline.
Time frame: Baseline, 12 months
Change in percent body fat on DEXA
Percent body fat was assessed in percentage using Dual Energy x-ray absorptiometry (DEXA). The change in percent body fat from baseline to 12 months was compared between the two diet groups. A negative change indicates a decrease in percent body fat from baseline.
Time frame: Baseline, 12 months
Change in HbA1c
HbA1c is the proportion of hemoglobin in the blood that has glucose attached to it relative to total hemoglobin. It reflects average blood glucose levels over approximately the previous 2-3 months. To assess the effect of dietary intervention on HbA1c, the change in HbA1c from baseline to 4 months was compared between the two diet groups. A negative change indicates an improvement in HbA1c from baseline.
Time frame: Baseline, 4 months
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