Trimming Obesity: A Vital Step Forward In Disease Prevention

“A Healthy People 2030 objective is to reduce the proportion of US adults with obesity. The baseline in 2013–2016 was 38.6%. The target for 2030 is 36%. Current status: Getting worse—in 2017–2020, 41.8% of US adults were obese.”                                                                                      —Healthy People 2030¹

In a sign of the times, the American Diabetes Association (ADA) and American Academy of Family Physicians (AAFP) have teamed up on a series of seven podcasts titled “Special Edition: A Focus on Obesity.”² Four episodes are designed for healthcare professionals, and three episodes are directed to people with diabetes and their caregivers. The series addresses obesity not simply as a lifestyle matter but as “a complex, chronic disease requiring a nuanced approach to management.”² Funding support comes from Novo Nordisk and Lilly.

The dimensions of the challenge are sobering; rates of obesity in the United States have tripled in the past 50 to 60 years, such that 1 in 3 adults is overweight, 2 in 5 are obese, and 1 in 11 has severe obesity. Among children and adolescents, 1 in 6 is overweight and 1 in 5 is obese.^2,3 Obesity increases the risk of a long list of diseases, from type 2 diabetes, heart disease and stroke, to liver and kidney disease, certain cancers, osteoarthritis, sleep apnea, and gallbladder and pancreatic diseases. Obesity also heightens the risk of low self-esteem, body image problems, depression, and eating disorders.⁴

Management of obesity and overweight is important enough to command a chapter of its own in the ADA’s 2024 Standards of Care in Diabetes.⁵ The topic is also a recurring theme in several other chapters, including one on delaying or preventing the onset of diabetes⁶ and another on facilitating positive health behaviors and well-being to improve outcomes.⁷

Disease prevention: an uphill battle
Obesity—along with other factors such as age, diet, physical activity, smoking, and drinking alcohol—figures prominently in the two leading causes of death in the US: heart disease and cancer. These factors are also key players in diabetes, the eighth leading cause of death, which claims more than 100,000 lives a year.⁸ As the Centers for Disease Control and Prevention (CDC) notes, “In the last 20 years, the number of adults diagnosed with diabetes has more than doubled as the American population has aged and become more overweight or obese.”⁹ An estimated 30%­­–53% of newly diagnosed cases of diabetes can be attributed to obesity, making it “the major driver of incident diabetes mellitus compared with other known risk factors.”¹⁰

Despite the frightful tolls taken by these diseases, prevention has long been an uphill battle. Data from the federal government’s Healthy People 2030 initiative show that only 21% of physician office visits by adults who are obese include education or counseling on losing weight, improving nutrition, or increasing physical activity.¹ Overall use of clinical preventive services is low and has actually declined in recent years.¹¹ In 2015, only 8.5% of US adults 35 years of age and older received all the recommended high-priority clinical preventive services. In 2020, that figure dropped to 5.3%.¹¹ The COVID-19 pandemic did not help, and other factors are also at work, including low awareness of preventive services and lack of access to healthcare.

The good news is that prevention programs can and do work. The picture is destined to brighten further as drugs for achieving significant weight loss gain wider use. In this article, we will focus on the risk factors of obesity and overweight and the measurable results of diabetes prevention programs. Most initiatives, including the CDC’s own National Diabetes Prevention Program,¹² seek to enroll people with prediabetes, a risk factor not just for diabetes but also for stroke and cardiovascular disease. The CDC estimates that 38% of adults in the US (98 million people) have prediabetes, but only 19% with the condition have been told by a health professional that they have it.¹³

“There is strong and consistent evidence that obesity management can delay the progression from prediabetes to type 2 diabetes and is highly beneficial in treating type 2 diabetes.”                                                                                                                               —ADA, Standards of Care in Diabetes—2024⁵

Gaining health by losing weight
The ADA’s 2024 Standards of Care for Diabetes recommend that adults who are overweight or obese and at high risk for type 2 diabetes be referred to a program of intensive lifestyle change, with a goal of losing at least 7% of their initial body weight through a combination of reduced calorie intake and an exercise plan of 150 minutes per week of moderately intense activity (eg, brisk walking).⁶ In addition to achieving and maintaining weight loss, goals include slowing the progression of hyperglycemia and reducing cardiovascular risk.⁶

People with prediabetes who participate in a structured program of lifestyle change, including weight loss of 5%–7%, can reduce their risk of developing type 2 diabetes by 58%. For people 60 years of age and older, the risk can be cut by 71%. These conclusions come from the Diabetes Prevention Program,¹⁴ a foundational precursor to the CDC’s current initiative that remains a classic point of reference.

The original Diabetes Prevention Program, a randomized controlled trial conducted from 1996–2001 at 27 centers in the US, included 3,234 adults without diabetes but with elevated fasting and post-load blood glucose levels.¹⁴ Participants were assigned to one of 3 groups: standard lifestyle recommendations plus placebo, standard lifestyle recommendations plus metformin, or an “intensive” lifestyle intervention program with the goals of achieving 7% weight loss and 150 minutes per week of moderate-intensity physical activity. The average age was 51 years of age, and the average body mass index (BMI) was 34 kg/m². The study group was diverse; 68% were women, and 45% were from minority groups.¹⁴

After an average follow-up period of 2.8 years (range: 1.8–4.6 years), lifestyle intervention reduced the incidence of diabetes by 58% compared to placebo (95% confidence interval [CI]: 48%–66%).¹⁴ Results were similar for men and women and across racial groups. Among participants taking metformin, there was a 31% reduction in the incidence of diabetes (95% CI: 17%–43%). Notably, 50% of the lifestyle intervention group achieved 7% weight loss by the end of a 24-week curriculum, and 38% maintained that loss at the time of the last visit in the study period.¹⁴

The Diabetes Prevention Program investigators regarded weight loss as an important mediator in preventing the development of type 2 diabetes or delaying its onset. Every kilogram of weight loss was accompanied by a 16% reduction in the risk of progression to diabetes.¹⁵

A follow-up conducted approximately 10 years after randomization in the Diabetes Prevention Program included 88% of the original participants.¹⁶ Cumulative diabetes incidence since the time of randomization was reduced by 34% in the lifestyle intervention group and 18% in the metformin group in comparison to the placebo group. Incidence rates were similar across all 3 groups during the follow-up period itself, when everyone had an opportunity to access a lifestyle intervention program. Lifestyle intervention delayed the onset of diabetes by approximately 4 years versus the placebo and metformin by about 2 years.¹⁶ At the 15-year follow-up, the cumulative incidence of diabetes was reduced by 27% in the lifestyle intervention group and 18% in the metformin group relative to placebo.¹⁷

The National Diabetes Prevention Program
The CDC’s National Diabetes Prevention Program, authorized by Congress in 2010, is modeled on the original Diabetes Prevention Program. A wide-ranging partnership of public and private stakeholders, the initiative describes itself as a Lifestyle Change Program, emphasizing the basics of eating right, losing weight, and becoming more active.¹²

The program is set up as a yearlong effort, starting with a CDC-approved curriculum of 16 training sessions with a lifestyle coach over a 6-month period, followed by 6 months of reinforcement and maintenance. Programs are available in person, remotely, or in combination.¹² The CDC’s Diabetes Prevention Recognition Program provides a national registry of authorized providers.¹⁸ The expectation is that goals and interventions for achieving and sustaining weight loss will be individualized.

Participation in the program is open to individuals 18 years of age and older, with a BMI of 25 or higher (23 if Asian), who are not pregnant, and have not had a prior diagnosis of type 1 or 2 diabetes (gestational diabetes is acceptable). Prediabetes is typically determined by a blood test showing fasting blood glucose of 100–125 mg/dL, A1c of 5.7%–6.4%, or post-load plasma glucose of 140–199 mg/dL. Criteria are slightly different for the Medicare Diabetes Prevention Program (eg, fasting plasma glucose of 110–125 mg/dL).¹⁹

In the first 4 years of the CDC’s program (2012–2016), 36% of participants achieved a 5% weight loss.²⁰ The study included more than 14,000 enrollees who attended a median of 14 sessions over an average of 172 days. The longer people stuck with the program, the better their results. Median weight loss was 6% for people who attended at least 17 sessions and remained in the program for 7 to 12 months, versus a median weight loss of 1.9% for those attending 2 to 16 sessions over 1 to 6 months.²⁰

The Healthy People 2030 initiative currently has a goal in development to increase the proportion of eligible people who complete CDC-recognized programs in diabetes prevention.¹ Baseline data are not yet available.

While the focus of the CDC prevention program is on achieving weight loss through healthy food selection, calorie restriction, and increased physical activity, the ADA’s Standards of Care in Diabetes for 2024 note that many FDA-approved obesity medications can slow the progression to type 2 diabetes in individuals at risk.⁵ With drugs now capable of generating weight loss well beyond the 7% objectives of traditional diabetes prevention programs, the options for a wide range of disease prevention and wellness programs are rapidly evolving. As the ADA/AAFP podcast noted, diet and exercise will remain a bedrock approach to weight loss and better health, with pharmacology providing a propellant.²

Newer weight loss agents are approved as an adjunct to diet and physical activity for treating people who are obese (BMI 30 or higher) or who are overweight (BMI 27 or higher) and have at least 1 weight-related comorbidity, such as cardiovascular disease, type 2 diabetes, hypertension, dyslipidemia, or obstructive sleep apnea.

Results from other prevention studies
In the US and around the world, diabetes prevention programs have produced promising results:

• A meta-analysis of 44 studies published in the US from 2003 to 2016, evaluating Diabetes Prevention Program-style intervention programs, reported “clinically meaningful” reductions in weight and cardiometabolic risk factors. The programs enrolled a total of 9,000 participants and typically conducted 12 to 16 sessions.²¹
• A meta-analysis of 53 studies encompassing 66 programs of diet and physical activity reported “strong evidence of effectiveness in reducing new-onset diabetes” along with improvement in cardiometabolic risk factors such as overweight, high blood pressure, and abnormal lipid profiles.²²
• The Finnish Diabetes Prevention Study offered a program of diet and exercise for a median of 4 years (range 1–6 years), after which people who remained free of diabetes were followed for up to 3 years, with no intervention provided. The initial study group (intervention and controls) included 522 middle-aged men and women with impaired glucose tolerance. Lifestyle modification produced a 43% reduction in the incidence of diabetes versus controls over the total period and a 36% reduction during the 3-year follow-up period.²³ Further follow-up 13 years after baseline showed a 39% reduction in the risk of diabetes among the former intervention group over the entire time and a reduction of 33% during the median 9 years of post-intervention follow-up.²⁴
• In China, the Da Qing Diabetes Prevention Study began as a 6-year project in 1986, enrolling 577 adults with impaired glucose tolerance. Participants were assigned to 1 of 3 intervention groups (diet, exercise, and diet plus exercise) or a control group. After 30 years, follow-up information was available for 84% of the original participants. The combined intervention groups experienced a median delay of 3.96 years in the onset of type 2 diabetes. They also experienced fewer cardiovascular events than controls with a hazard ratio (HR) of 0.74, a lower rate of microvascular complications (HR: 0.65), fewer cardiovascular deaths (HR: 0.67), and lower all-cause mortality (HR: 0.74).²⁵

“In people with type 2 diabetes and overweight or obesity, modest weight loss improves glycemia and reduces the need for glucose-lowering medications. Larger weight loss substantially reduces A1c and fasting glucose and may promote sustained diabetes remission.”                                                         —ADA, Standards of Care in Diabetes—2024⁵

Weight loss in treating established type 2 diabetes
While the focus in this report is on prevention of diabetes and other obesity-related diseases, weight loss is also a core element in the treatment of most patients with established type 2 diabetes. While emphasizing the importance of individualizing treatment, the ADA’s recommended options range from lifestyle interventions focused on diet and exercise to intensive, structured weight management programs, pharmacotherapy, and metabolic surgery.⁵

The ADA recommends nutrition guidance, physical activity, and behavioral therapy to help patients with type 2 diabetes who are overweight or obese to achieve and maintain a weight loss of 5% or greater. More ambitious weight loss goals of 7%, 10%, 15%, or more “may be pursued to achieve further health improvements if the individual is motivated and more intensive goals can be feasibly and safely attained.”⁵ Weight loss of more than 10% not only improves control of diabetes but also “improves other metabolic comorbidities, including cardiovascular outcomes, nonalcoholic steatohepatitis, nonalcoholic fatty liver disease, adipose tissue inflammation, and sleep apnea, as well as physical comorbidities and quality of life.”⁵

While a number of pharmacologic agents can produce clinically meaningful weight loss, the ADA recommends that “in people with type 2 diabetes and overweight or obesity, agents with both glucose-lowering and weight loss effects are preferred.”⁵ This description includes glucagon-like peptide-1 (GLP-1) receptor agonists and dual GLP-1 and glucose-dependent insulinotropic polypeptide receptor agonists.

The ADA further recommends a regimen that includes a glucose-lowering agent with high to very high efficacy for weight loss. Tirzepatide and semaglutide have very high efficacy, according to the ADA, and dulaglutide and liraglutide have high efficacy.²⁶

References

1. Healthy People 2030. Overweight and obesity. Accessed May 22, 2024.
2. American Diabetes Association and American Academy of Family Physicians. A focus on obesity: a special podcast series from ADA and AAFP. Accessed May 22, 2024.
3. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Overweight & obesity statistics. Accessed May 24, 2024.
4. NIDDK. Health risks of overweight and obesity. Accessed May 26, 2024.
5. American Diabetes Association Professional Practice Committee. Standards of Care in Diabetes—2024. 8. Obesity and weight management for prevention and treatment of type 2 diabetes. Diabetes Care. 2024;47(suppl 1):S145–S157.
6. American Diabetes Association Professional Practice Committee. Standards of Care in Diabetes—2024. 3. Prevention or delay of diabetes and associated comorbidities. Diabetes Care. 2024;47(suppl 1):S47–S51.
7. American Diabetes Association Professional Practice Committee. Standards of Care in Diabetes—2024. 5. Facilitating positive health behaviors and well-being to improve health outcomes. Diabetes Care. 2024;47(suppl 1):S77–S110.
8. Centers for Disease Control and Prevention (CDC). Leading causes of death. Accessed May 14, 2024.
9. CDC. About the Division of Diabetes Translation. Accessed May 21, 2024.
10. Cameron NA, Petito LC, McCabe M, et al. Quantifying the sex-race/ ethnicity-specific burden of obesity on incident diabetes mellitus in the United States, 2001 to 2016: MESA and NHANES. J Am Heart Assoc. 2021;10(4):3018799.
11. Reed P. Prevention is still the best medicine. Office of Disease Prevention and Health Promotion, US Department of Health and Human Services. January 26, 2024. Accessed May 15, 2024.
12. CDC. National Diabetes Prevention Program. Accessed May 21, 2024.
13. CDC. National Diabetes Statistics Report. Accessed May 21, 2024.
14. Knowler WC, Barrett-Connor E, Fowler SF, et al. Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes by lifestyle intervention or metformin. N Engl J Med. 2002;346(6):393–403.
15. Hamman RF, Wing RR, Edelstein SL, et al. Effect of weight loss with lifestyle intervention on risk of diabetes. Diabetes Care. 2006;29(9):2102–2107.
16. Diabetes Prevention Program Research Group. Knowler WC, Fowler SE, Hamman RF, et al. 10-year follow-up of diabetes incidence and weight loss in the Diabetes Prevention Program Outcomes Study. Lancet. 2009;374(9702):1677–1686.
17. Diabetes Prevention Program Research Group; Nathan DM, Barrett-Connor E, Crandall JP. Long-term effects of lifestyle intervention or metformin on diabetes development and microvascular complications over 15-year follow-up. Lancet Diabetes Endocrinol. 2015;3(11):866–875.
18. CDC. National Registry of Recognized Diabetes Prevention Programs. Accessed May 22, 2024.
19. CDC. Preventing type 2 diabetes with Medicare. Accessed May
20. Ely EK, Gruss SM, Luman ET, et al. A national effort to prevent type 2 diabetes: participant level evaluation of CDC’s National Diabetes Prevention Program. Diabetes Care. 2017;40(10):1331–1341.
21. Mudaliar U, Zabetian A, Goodman M, et al. Cardiometabolic risk factor changes observed in diabetes prevention programs in US settings: a systematic review and meta-analysis. PLoS Med. 2016;13:e1002095.
22. Balk EM, Early AM, Raman G, et al. Combined diet and physical activity promotion programs to prevent type 2 diabetes among persons at increased risk: a systematic review for the community services preventive task force. Ann Intern Med. 2015;163:437–451.
23. Lindstrom J, Ilanne-Parikka P, Peltonen M, et al; Finnish Diabetes Study Group. Sustained reduction in the incidence of type 2 diabetes by lifestyle intervention: follow-up of the Finnish Diabetes Prevention Study. Lancet. 2006;368(9548):1673–1679.
24. Lindstrom J, Peltonen M, Eriksson JG, et al. Improved lifestyle and decreased diabetes risk over 13 years: long-term follow-up of the randomized Finnish Diabetes Prevention Study (DPS). Diabetologia. 2013;56(2):286–293.
25. Gong Q, Zhang P, Wang J, et al; Da Qing Diabetes Prevention Study Group. Morbidity and mortality after lifestyle intervention for people with impaired glucose tolerance: 30-year results of the Da Qing Diabetes Prevention outcome Study. Lancet Diabetes Endocrinol. 2019;7(6):452–461
26. American Diabetes Association Professional Practice Committee. Standards of Care in Diabetes—2024. 9. Pharmacologic approaches to glycemic treatment. Diabetes Care. 2024;47(suppl1):S158–S178.

Helpful Resources

Rosenzweig JL, Bakris GL, Berglund LF, et al. Primary prevention of ASCVD and T2DM in patients at metabolic risk: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2019;104(9):3939–3985.

MyHealthfinder, a website offered by the HHS Office of Disease Prevention and Health Promotion. Information for families is available on 100 health topics. Health professionals can post the educational materials for free on their own websites.

CDC Diabetes Prevention Impact Toolkit

Dietary Guidelines for Americans

CDC Division of Diabetes Translation

Office of Disease Prevention and Health Promotion, HHS