Diabetes Prevention and Control: Combined Diet and Physical Activity Promotion Programs to Prevent Type 2 Diabetes Among People at Increased Risk
Task Force Finding
The Community Preventive Services Task Force recommends combined diet and physical activity promotion programs for people at increased risk of type 2 diabetes based on strong evidence of effectiveness in reducing new-onset diabetes. Combined diet and physical activity promotion programs also increase the likelihood of reverting to normoglycemia (normal blood sugar) and improve diabetes and cardiovascular disease risk factors, including overweight, high blood glucose, high blood pressure, and abnormal lipid profile.
Based on the evidence, combined diet and physical activity promotion programs are effective across a range of counseling intensities, settings, and implementers. Programs commonly include a weight loss goal, individual or group sessions (or both) about diet and exercise, meetings with a trained diet or exercise counselor (or both), and individually tailored diet or exercise plans (or both). Higher intensity programs lead to greater weight loss and reduction in new-onset diabetes.
Economic evidence indicates that combined diet and physical activity promotion programs to prevent type 2 diabetes among people at increased risk are cost-effective.
Read the full Task Force Finding and Rationale Statement for details including implementation issues, possible added benefits, potential harms, and evidence gaps.
Combined diet and physical activity promotion programs aim to prevent type 2 diabetes among people who are at increased risk of the disease. These programs actively encourage people to improve their diet and increase their physical activity using the following:
- Trained providers in clinical or community settings who work directly with program participants for at least 3 months
- Some combination of counseling, coaching, and extended support
- Multiple sessions related to diet and physical activity, delivered in-person, or by other methods
Programs may also use one or more of the following:
- Providers who are diet counselors of different specialties (for example, nutritionists, dietitians, diabetes educators), exercise counselors of different specialties (for example, physical educators, physiotherapists, trainers), physicians, nurses, trained laypeople, and others
- A range of intensity in the counseling, with numerous or few sessions, longer or shorter duration sessions, and individual or group sessions
- Individually tailored or generic diet or physical activity programs
- Specific weight loss or exercise goals
- A period of maintenance sessions following the primary core period of the program
Program participants may be considered at increased risk of type 2 diabetes if they have blood glucose levels that are abnormally elevated, but not high enough to be classified as type 2 diabetes.1 Participants may also be identified using diabetes risk assessment tools.
About the Systematic Review
The Task Force finding is based on evidence from a systematic review of 53 studies that described 66 programs (search period January 1991 - February 2015). The review was conducted on behalf of the Task Force by a team of specialists in systematic review methods, and in research, practice and policy related to diabetes prevention and control.
- Among populations at increased risk of type 2 diabetes, combined diet and physical activity promotion programs led to improvements in health outcomes and risk factors for type 2 diabetes and cardiovascular disease compared with usual care.
- The proportion of people who developed type 2 diabetes decreased by a median of 11 percentage points (interquartile interval [IQI]: 5 to 16; 16 studies).
- The proportion of people who achieved normal blood sugar (normoglycemia) increased by a median of 12 percentage points (IQI: 6 to 14; 6 studies).
- Body weight was reduced by an average of 2.2% (95% confidence interval [CI]: 1.4 to 2.9; 24 studies).
- Fasting blood glucose was reduced (improved) by an average of 2.2 mg/dL (95% CI 0.9 to 3.6; 17 studies) and hemoglobin A1c (a measure of long-term glucose levels) was reduced (improved) by an average of 0.08 percentage points (95% CI 0.04 to 0.12; 8 studies).
- Blood pressure (17 studies) and cholesterol levels (13 studies) also were improved.
- The effect on mortality was unclear. Mortality was reduced by 2 to 10 percentage points (2 studies) or by 0.6 per 1000 person-years (1 study) over 3 to 23 years of follow-up. However, this benefit was statistically significant in only one study, and in that study only among women.
- Regardless of program features, almost all programs led to weight loss, reduced risk of diabetes, or both. However, among 12 studies with direct comparisons, more intensive programs (based on features such as number of sessions, individual sessions, and additional personnel) resulted in greater weight loss and lower rates of diabetes than less intensive programs. Across studies, more effective programs provided:
- Individual (vs. group) exercise sessions,
- Individual (vs. group) diet sessions, or
- Diet counselors
- In studies of programs that used protocols outlined by the U.S. Diabetes Prevention Program (DPP) study or Finnish Diabetes Prevention Study (DPS), or modifications of them, participants lost more weight (3% of initial body weight) than participants in programs not based on DPP or DPS (1.6% of initial body weight; P=0.051), but reductions in risk of developing diabetes were similar between studies of different programs.
- Programs lasted between 3 months and 6 years, with a median of 12 months (IQI: 10 to 27 months).
- The core period lasted between 1 month and 5 years, with a median of 6 months (IQI: 5 to 12 months).
- Maintenance periods (in 28 programs) lasted between 4 and 68 months, with a median of 12 months (IQI: 7 to 18 months).
- Programs provided between 0 (virtual sessions only) and 72 sessions, with a median of 15 sessions (IQI: 6.5 to 24.5 sessions).
- During the core period, there were between 0 (virtual only) and 72 sessions, with a median of 10 sessions (IQI: 6 to 16 sessions).
- During the maintenance period (in 28 programs), there were between 0 (virtual only) and 24 sessions, with a median of 6 sessions (IQI: 1.5 to 12 sessions). In some programs, the maintenance period contacts were by telephone or email only.
- Programs used individual face-to-face meetings (40 programs included individual diet sessions, 41 programs included individual exercise sessions), group meetings (diet: 41 programs, exercise: 39 programs), or both (diet: 24 programs, exercise: 24 programs). Five programs were conducted via web-tools, social networking, email, text messaging, video (or a combination of these) with no in-person sessions.
- Sessions were led by different combinations of trained diet counselors including dietitians, nutritionists, or others (37 programs); trained exercise counselors including physical trainers or others (26 programs); nurses (15 programs); physicians or psychologists (8 programs); and trained laypeople (13 programs).
- Programs included specific weight loss goals (42 programs), diet goals (19 programs), and physical activity goals (32 programs).
- Programs included individually tailored plans for diet (16 programs) and physical activity (23 programs).
- Studies were conducted in the United States (21 studies), Europe (17 studies), and other countries.
Based on results for programs in different settings and populations, findings are applicable to the following:
- Adults at increased risk of type 2 diabetes
- Older adults were shown to have greater benefits
- Adolescents (based on two studies)
- Women and men
- All racial and ethnic groups
- All socioeconomic levels
- Urban and rural environments
- Healthcare and community-based settings in the United States
An economic review of 28 studies (search period January 1985 - April 2015) shows that combined diet and physical activity promotion programs for people at increased risk for type 2 diabetes are cost-effective. All monetary values reported are in 2013 U.S. dollars.
Cost of the programs:
- All programs: median $653 per participant (IQI: $383 to $1,160; 12 studies)
- Group-based programs: median $417 per participant (IQI: $341 to $600; 8 studies)
- Programs that translated the U.S. DPP into community or primary care settings: median $424 per participant (IQI: $340 to $793; 8 studies)
Cost-effectiveness of the program (from the health system perspective, which included only the direct medical costs of the programs and healthcare costs averted, based on either data collected in actual programs or estimates from simulation models):
- Cost per quality-adjusted life year (QALY) saved:
- All programs: median $13,761 (IQI: $3,067 to $21,899; 16 studies)
- Group-based programs: median $1,819 (IQI: −$5,027 to $16,443; 5 studies)
- Individual-based programs: median $15,846 (IQI: $7,980 to $72,723; 5 studies)
- Cost per disability-adjusted life year (DALY) averted:
- $21,195 and $50,707 (2 studies)
- Cost per life year gained (LYG):
- Median $2,684 (IQI: −$2,444 to $17,410; 6 studies)
The variation in program costs per participant is partly explained by the number of sessions, delivery mode of the core sessions (individual vs. group), setting (clinical trial vs. community or primary care), and type of personnel used (health professionals vs. trained laypeople). The variation in cost-effectiveness is partially explained by variation in cost and effectiveness of the programs, program delivery modes, patient follow-up times, and delivery settings.
Considerations for Implementation
The following considerations are drawn from studies included in the evidence review, the broader literature, and expert opinion. The Community Guide does not conduct systematic reviews of implementation.
- In 2010, the U.S. Congress authorized CDC to establish the National Diabetes Prevention Program (National DPP), an alliance of public and private organizations (including insurers) managed by CDC to achieve wide-scale implementation and coordination of lifestyle change programs to prevent or delay type 2 diabetes. As of May 2014, more than 500 organizations in all states and the District of Columbia have applied for CDC recognition for their diabetes prevention programs. More information about the National DPP can be found at www.cdc.gov/diabetes/prevention .
- Combined diet and physical activity promotion programs have been successfully implemented by several national and state-wide organizations, the majority of which are part of the National DPP.
- Healthcare providers are usually the primary resource for individuals newly diagnosed with being at increased risk of type 2 diabetes. Providers need to be aware of the benefits of combined diet and physical activity promotion programs and of local programs, which may be offered by community centers, insurer-run programs, or non-profit or other private contractors among others.
- Organizations implementing combined diet and physical activity promotion programs may want to address factors that make it difficult for some people to participate. Examples include limited ability to pay for program services; limited time to cook or exercise due to work schedules or childcare needs; limited access to inexpensive and healthful food, safe and convenient places to exercise and transportation there; and cognitive or physical disabilities.
1People are classified as being at increased risk of type 2 diabetes if their blood glucose levels are abnormally elevated but still below the threshold for the disease. People at increased risk of diabetes have hemoglobin levels between 5.7% and 6.4%, fasting plasma glucose between 100 and 125 mg/dL, or plasma glucose between 140 and 199 mg/dL after a 75 gram oral glucose tolerance test (American Diabetes Association, 2010).
- Analytic Framework [PDF - 111.12 kB]
- Evidence Gaps
- Summary Evidence Tables - Effectiveness Review
- Study Characteristics [PDF - 414 kB]
- Patient Characteristics [PDF - 432 kB]
- Intervention Characteristics
- Combined Diet & Physical Activity vs. Control [PDF - 385 kB]
- More vs. Less Intensive Combined Diet & Physical Activity [PDF - 317 kB]
- Before-After Combined Diet & Physical Activity Studies [PDF - 282 kB]
- Studies Using Trainers or Dieticians [PDF - 286 kB]
- Results of Studies
- Combined Diet & Physical Activity vs. Control [PDF - 1.33 MB]
- More vs. Less Intensive Combined Diet & Physical Activity [PDF - 559 kB]
- Before-After Combined Diet & Physical Activity Studies [PDF - 288 kB]
- Quality Assessment of Studies [PDF - 296 kB]
- Summary Evidence Table - Economic Review [PDF - 133 kB]
- Included Studies - Effectiveness Review
- Included Studies - Economic Review
- Search Strategy - Effectiveness Review
- Search Strategy - Economic Review
Balk EM, Earley A, Raman G, Avendano EA, Pittas AG, Remington PL. Combined diet and physical activity promotion programs to prevent type 2 diabetes among persons at increased risk: a systematic review for the Community Preventive Services Task Force [PDF - 422 kB]. Ann Intern Med 2015;163. doi:10.7326/M15-0452
Li R, Qu S, Zhang P, Chattopadhyay S, Gregg EW, Albright A, et al. Economic evaluation of combined diet and physical activity promotion programs to prevent type 2 diabetes among persons at increased risk: a systematic review for the Community Preventive Services Task Force [PDF - 230 kB]. Ann Intern Med 2015;163. doi:10.7326/M15-0469
Pronk NP, Remington PL; Community Preventive Services Task Force. Combined diet and physical activity promotion programs for prevention of diabetes: Community Preventive Services Task Force recommendation statement [PDF - 76 kB]. Ann Intern Med 2015;163. doi:10.7326/M15-1029
Pronk NP. Systematic review with meta analysis: structured diet and physical activity programmes provide strong evidence of effectiveness for type 2 diabetes prevention and improvement of cardiometabolic health . Evid Based Med 2015; doi:10.1136/ebmed-2015-110292.
Ackermann RT. Diabetes prevention at the tipping point: aligning clinical and public health recommendations [PDF - 55 kB]. Ann Intern Med 2015;163. doi:10.7326/M15-1563
Read other Community Guide publications about Diabetes Prevention and Control in our library.
Community Guide News
- Community Guide News: Now Published! Task Force Says Diet + Physical Activity Programs Help People at Risk for Type 2 Diabetes
Developed by The Community Guide
- Combined Diet and Physical Activity Promotion Programs to Prevent Type 2 Diabetes Among People at Increased Risk [PDF - 454 kB]
Developed by The Community Guide
More promotional materials for Community Guide reviews about Diabetes Prevention and Control.
American Diabetes Association. Diagnosis and classification of diabetes mellitus. Diabetes Care 2010;33 (Suppl 1):S62-9.
The findings and conclusions on this page are those of the Community Preventive Services Task Force and do not necessarily represent those of CDC. Task Force evidence-based recommendations are not mandates for compliance or spending. Instead, they provide information and options for decision makers and stakeholders to consider when determining which programs, services, and policies best meet the needs, preferences, available resources, and constraints of their constituents.
The content of publications of the Guide to Community Preventive Services is in the public domain. Citation as to source, however, is appreciated. Sample citation: Guide to Community Preventive Services. Diabetes prevention and control: combined diet and physical activity promotion programs to prevent type 2 diabetes among people at increased risk. www.thecommunityguide.org/diabetes/combineddietandpa.html. Last updated: MM/DD/YYYY.
Review completed: July 2014
- Page last reviewed: July 16, 2015
- Page last updated: November 9, 2015
- Content source: The Guide to Community Preventive Services