| Study summary: |
|
Obesity can lead to many serious health conditions, including high blood pressure, diabetes,
heart disease, and stroke. It is estimated that more than 65% of adults in the United States
are overweight or obese, which is a significant increase over the past two to three decades.
Although numerous studies have identified successful programs that help people achieve
initial weight loss, few weight loss programs have shown promise for long-term success.
Research has shown that a weight loss program in which there is continued contact between
the program leader and the participant may improve long-term weight loss outcomes. In
addition, a stepped-care approach to weight loss, in which contact between the participant
and program leader increases when needed to achieve the next weight loss goal, may be
beneficial. This study will examine whether a long-term weight loss program delivered in a
stepped-care manner results in greater weight loss than does a standard behavioral weight
loss program. Study researchers will also evaluate the cost effectiveness of both programs.
Participants in this 18-month study will be randomly assigned to either a standard
behavioral weight loss program or a stepped-care weight loss program. Participants in the
standard behavioral weight loss program will attend group meetings once a week for Months 1
to 6, every other week for Months 7 to 12, and once a month for Months 13 to 18. The group
meetings will focus on modifying eating habits and physical activity behaviors to improve
weight loss. Participants in the stepped-care weight loss program will take part in a
combination of treatments, whose timing and intensity will depend on the participants'
abilities to achieve predetermined weight loss goals. These treatments may include attending
monthly group meetings, receiving weekly weight loss information in the mail, receiving
telephone calls from study staff to discuss weight loss behaviors, taking part in individual
sessions with study staff to discuss weight loss, and receiving meal replacements (e.g.,
Slim Fast shakes, meal bars). Participants who do not achieve their weight loss goals at
select time points during the study will receive more individual attention from study staff.
All participants will follow a diet that focuses on decreasing calories and fat. They will
be instructed to follow a walking program 5 days a week and to keep a food and exercise
diary. Participants will also have access to a Web site that will include a study calendar
and information about how to change eating and exercise behaviors; the use of this Web site
is optional.
Study visits will occur at baseline and Months 3, 6, 9, 12, 15, and 18. At each visit,
participants' weight and height will be measured, and participants will complete
questionnaires about their mood, general health, and exercise and diet habits. At baseline
and Months 6, 12, and 18, participants will undergo measurements of blood pressure, fat,
muscle, and waist and hip circumferences. Also at these times, physical fitness levels will
be measured through a treadmill walking activity, during which an electrocardiogram (ECG)
will record heart rate. For 7 consecutive days at baseline and Months 6, 12, and 18,
participants will wear an activity monitor to measure physical activity levels. |
| Criteria: |
|
Inclusion Criteria:
- Body mass index (BMI) between 25.0 and 39.9 kg/m2
Exclusion Criteria:
- Reports losing more than 5% of current body weight in the 6 months before study entry
- Participated in a research project involving weight loss or physical activity in the
6 months before study entry
- Pregnant during the 6 months before study entry, currently breastfeeding, or planning
to become pregnant in the 18 months after study entry
- Current treatment for any medical condition that could affect body weight (e.g.,
diabetes mellitus, cancer)
- History of heart attack or heart surgery, including bypass or angioplasty
- Currently taking medication that would affect heart rate or blood pressure responses
to exercise (e.g., beta blockers)
- Currently taking medication that could affect metabolism or change body weight (e.g.,
synthroid)
- Currently being treated for psychological issues or has taken psychotropic
medications in the 6 months before study entry |