U.S. Department of Health and Human Services

Long-term Lifestyle Change for Type 2 Diabetes and Obesity Study: Look AHEAD

Purpose

The NIDDK funded the Look AHEAD (Action for Health in Diabetes) study to evaluate whether weight loss lowered the risk for cardiovascular disease events such as heart attack and stroke—and other health problems—in people who were overweight or obese and had type 2 diabetes. Researchers looked at whether participants could lose weight and keep it off through a lifestyle intervention program involving increased physical activity and healthy eating. Few, if any, studies of this size and length have had similar success in helping participants reach and maintain a significant weight loss.

In the United States, type 2 diabetes is the most common form of diabetes in adults. Type 2 diabetes occurs when people have higher-than-normal levels of blood glucose, also called blood sugar. Over time, high blood glucose increases the risk for serious health problems such as cardiovascular disease, kidney disease, eye disorders, and nerve diseases. Overweight and obesity are linked to higher risks of other diseases and conditions, including type 2 diabetes and cardiovascular disease. Overweight (Body Mass Index [BMI] 25.0-29.9) and obesity (BMI ≥ 30.0) now affect about 70 percent of adult Americans. 

Results

Encouraging results from the first years of the study showed that people who have obesity and type 2 diabetes can lose weight and maintain weight loss through a lifestyle intervention program. These results are important because earlier research suggested that weight loss and maintenance might be more difficult in people with type 2 diabetes who are also overweight or obese.

After one year, people who took part in the lifestyle intervention program lost about 9 percent of their weight, while people who received only diabetes support and education lost less than 1 percent of their weight. After 8 years, people in the lifestyle intervention program kept up a weight loss of nearly 5 percent, an amount that experts recommend to improve health, while people in the diabetes support and education group gradually lost about 2 percent of their body weight over time.

Although participants in the lifestyle intervention program successfully achieved their weight loss goals, there was no difference in cardiovascular events between the two groups. However, intervention group participants gained other health benefits, including improved:

  • blood pressure levels
  • blood glucose levels
  • blood cholesterol levels
  • fitness levels
  • mobility
  • quality of life
  • medication use
  • health care costs
  • sleep apnea (problems breathing during sleep)
  • urinary incontinence
  • hospitalization frequency

Since the study did not find a difference in the number of cardiovascular events, the lifestyle intervention program was stopped in September 2012. Researchers are continuing to follow participants to evaluate whether they experience other health benefits over the long-term.

Study Size, Participant Demographics, Study Design, and Follow-up

The Look AHEAD recruitment and intervention took place from 2001 to 2012. Researchers continue to study the participants to identify longer term results of the study.

More than 5,100 adults—ages 45 to 76 with type 2 diabetes and who were overweight or obese—were enrolled at the start of the study and participated in a lifestyle change program for up to 11 years. Participants included men and women, and about one third were members of minority groups that are more likely to have diabetes and obesity.

Participants were assigned to one of two groups: an intensive lifestyle intervention program group, or a diabetes support and education group (standard group). People in the lifestyle intervention program were given weekly one-on-one and group counseling sessions for the first 6 months of the study and 3 group counseling sessions per month during months 6-12 of the study. After that, the meetings continued but were less often. The participants’ goal was to lose and keep off at least 7 percent of their body weight by eating prepared meals and liquid meals with fewer calories and doing at least 175 minutes of moderate or intense physical activity per week. For participants not able to meet the weight-loss goal with diet and physical activity alone, a weight-loss medicine could be added, if appropriate, to the lifestyle intervention changes. People in the standard group had just three group sessions per year on diet, exercise, and social support.

People in the study had yearly study visits. During the visits, they had their weight and blood pressure checked, and had exercise and blood tests to check fitness levels, diabetes control, and blood fat levels such as cholesterol. During yearly visits and telephone calls every 6 months, health care providers also gathered information from participants about medications, medical problems, and hospital stays.

Look AHEAD has been conducted at multiple centers across the country. The study’s coordinating center is at Wake Forest University in Winston-Salem, North Carolina. The clinical centers are at the following sites:

  • Johns Hopkins University, Baltimore, Maryland
  • Baylor College of Medicine, Houston, Texas
  • University of Colorado Health Sciences Center, Denver, Colorado
  • University of Washington, Seattle, Washington
  • University of Tennessee, Memphis, Tennessee
  • St. Luke’s-Roosevelt Institute for Health Sciences, New York, New York
  • The Miriam Hospital, Providence, Rhode Island
  • University of Alabama at Birmingham, Birmingham, Alabama
  • Pennington Biomedical Research Center, Baton Rouge, Louisiana
  • University of Texas Health Science Center, San Antonio, Texas
  • University of Minnesota, Minneapolis, Minnesota
  • University of Pittsburgh, Pittsburgh, Pennsylvania
  • Massachusetts General Hospital, Boston, Massachusetts
  • University of Southern California, Los Angeles, California
  • University of Pennsylvania, Philadelphia, Pennsylvania
  • Southwest American Indian Center, Phoenix, Arizona

In addition to the NIDDK, other sponsors included the following institutes and centers of the National Institutes of Health (NIH): the National Heart, Lung, and Blood Institute (NHLBI); National Institute of Nursing Research (NINR); the Office of Research on Women´s Health (ORWH); and the National Institute on Minority Health and Health Disparities (NIMHD). The study was also supported by the Centers for Disease Control and Prevention (CDC).

In 2016, the NIDDK, along with NIH’s National Institute on Aging (NIA), renewed support for Look AHEAD for 5 more years (now called Look AHEAD-Extension or Look AHEAD-E). The extended study will examine whether lifestyle changes (healthy eating and increased physical activity to lose weight) have lasting effects that will increase life span, lower health care costs, and have other long-term effects on healthy aging in older adults who have type 2 diabetes.

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