A Low-Carbohydrate Diabetes Prevention Program

An estimated 86 million US adults are have prediabetes, and, without intervention, many will
develop T2DM over time. Fortunately, T2DM can be prevented or delayed through modest
lifestyle changes. The landmark Diabetes Prevention Program (DPP) Trial demonstrated a 58
percent reduction in the 3-year incidence of T2DM among individuals with prediabetes who
achieved 7 percent body weight loss and engaged in routine physical activity. Accordingly,
the DPP lifestyle intervention has been translated to communities across the United States,
and, on average, participant weight change is 4 percent at 12 months. Thus, while group-based
DPPs and can effectively promote weight loss among some participants, many DPP participants
do not achieve the program goal of 5 to 7 percent body weight loss.

Novel strategies to help participants achieve DPP weight-loss goals are important for two key
reasons. First, weight loss is the primary driver of T2DM risk reduction, and the potential
population health impact of the intervention is diminished when participants do not lose
weight. Second, a growing number of health plans including Medicare offer coverage for the
DPP and proposed reimbursement is largely tied to weight loss of at least 5 percent at 6
months and 12 months. The DPP costs approximately $400-$500 per participant per year.
Unfortunately, organizations that offer the DPP may be reimbursed for much less than this if
participants do not meet weight loss goals, which could significantly compromise the
program's long-term financial sustainability.

One promising approach to help DPP participants lose more weight may be through a
low-carbohydrate (LC) dietary intervention. Consistent with United States Dietary Guidelines
(USDG), the original DPP Trial and translational group-based curricula recommend a low-fat
(LF), calorie-restricted diet. However, there is growing controversy regarding the scientific
merit of the Dietary Guidelines as well as growing recognition that LC diets may be more
effective than LF diets for short-term weight loss and long-term weight maintenance. Notably,
weight loss occurs without calorie restriction and LC diets improve blood glucose levels
among individuals with T2DM and insulin resistance. Thus, a LC dietary intervention for
prediabetes may augment individual weight loss and T2DM risk reduction while also maximizing
third-party reimbursement.

The aim of this mixed methods pilot study is to test whether a LC-DPP may lead to greater
weight loss than the original DPP. In addition to objective measures of this program's
preliminary efficacy (e.g. weight, HbA1c) the study team will also obtain qualitative
participant feedback on the intervention. Taken together, these data will be used to improve
the curriculum and inform a larger-scale intervention.

Inclusion criteria:

1. Overweight, defined as BMI≥25 kg/m2 [31]

2. HbA1c between 5.7-6.4% drawn within 6 months of the study start date

3. Willingness to participate in group-based classes

4. Able to engage in at least light physical activities such as walking.

Exclusion criteria:

1. History of type 1 diabetes or type 2 diabetes

2. Current participation in another lifestyle or behavior change program or research
study

3. Vegetarian or vegan lifestyle

4. History of bariatric surgery

5. Inability to read, write, or speak English

6. Inability to provide informed consent

7. Women who are pregnant or intend to become pregnant during the intervention period.

8. Insured by Premier Care or Grad Care; these individuals have the opportunity to
participate in a standard DPP, which is offered as a covered benefit through their
health plan.