Penn Study Finds Lifestyle Modification and Weight
Loss Medication Superior
to Either Approach Used Alone
Combination of both approaches increases weight loss two-fold
(Philadelphia, PA) - According to a study that appears in
the November 17 issue of The New England Journal of Medicine,
researchers at the University of Pennsylvania School of Medicine
found that weight loss medications work best when combined with dieters'
own efforts to modify their eating and exercise habits. Study participants
who received combined therapy lost significantly more weight than all
"Weight loss medications helped people lose weight, as did a program
of lifestyle modification designed to improve eating and exercise habits.
However, we found that a combination of the two approaches produced approximately
twice the weight loss of either intervention used alone," reported
Thomas A. Wadden, Ph.D., lead author of the paper and
director of the Weight and Eating Disorders Program at Penn. The research
was supported by the National Institute of Diabetes and Digestive and
Kidney Disease, one of the National Institutes of Health.
The one-year study examined 180 women and 44 men with an average age of
44 years, weight of 235 lb., and body mass index of 37.7 kg/m2. Participants
were randomly assigned to one of four treatment groups, all of which were
instructed to consume 1200-1500 calories a day and to exercise 30 minutes
a day, most days of the week.
Participants in the first group were prescribed 10-15 mg/d of the weight
loss medication sibutramine (MERIDIA™, Abbott Laboratories) and
had 8 brief (10-15 min) visits during the year with a primary care practitioner.
These individuals received minimal instruction in lifestyle modification,
consistent with the manner in which most physicians prescribe weight loss
Individuals in the second group received group lifestyle modification
alone, which is recommended as the first step of treatment for all overweight
and obese individuals. They attended a total of 30 group sessions (90
minutes each) over the year and were instructed to keep daily records
of their food intake and physical activity which were reviewed during
Participants in the third group received a combination of the first two
approaches (i.e., sibutramine plus group lifestyle modification) to determine
whether the combined therapy would be superior to either approach used
Individuals in the fourth group received sibutramine and met with a primary
care practitioner 8 times during the year, and were also encouraged to
keep daily food and activity records. This group was included to see if
practitioners could provide effective lifestyle modification counseling
during brief visits.
At the end of 1 year, participants in the four groups lost 11.0 lb (sibutramine
alone), 14.7 lb (group lifestyle modification alone), 26.6 lb (combined
therapy), and 16.5 lb (sibutramine plus brief lifestyle counseling), respectively.
Participants who received combined therapy lost significantly more weight
than those in the three other groups.
"These findings clearly indicate that weight loss medications are
most effective when combined with a comprehensive program of lifestyle
modification," said Robert Berkowitz, M.D., a co-author
of the study and Associate Professor of Psychiatry at Penn. "Sibutramine
appears to modify internal signals that control hunger and fullness, while
lifestyle modification teaches individuals to control the external food
environment - for example, by keeping food records or shopping for groceries
from a list," added Berkowitz, who is also Chair of Psychiatry, The
Children's Hospital of Philadelphia. Participants who received sibutramine
plus brief lifestyle counseling lost significantly more weight than those
treated by sibutramine alone during the first 18 weeks (18.7 vs 13.6 lb,
respectively), suggesting that primary care providers can provide effective
lifestyle counseling during routine office visits.
Examining all 224 participants, weight loss at the end of the year was
associated with a 14.7% reduction in triglyceride levels and an 18.9%
decrease in insulin resistance, a condition that usually precedes the
development of type 2 diabetes. Larger weight losses were associated with
greater improvements in these measures, as well as with greater improvements
in high-density-lipoprotein cholesterol (i.e., the "good" cholesterol).
"Our findings indicate that weight loss medications should be used
only as an adjunct to a program of lifestyle modification, as recommended
by both the National Institutes of Health and the Food and Drug Administration,"
said Wadden. "Lifestyle modification can begin with efforts to reduce
portion sizes, keep a daily food log, and increase daily walking. The
more approaches you combine, the less you'll weigh," he added.
PENN Medicine is a $2.7 billion enterprise dedicated
to the related missions of medical education, biomedical research, and
high-quality patient care. PENN Medicine consists of the University of
Pennsylvania School of Medicine (founded in 1765 as the nation's first
medical school) and the University of Pennsylvania Health System.
Penn’s School of Medicine is ranked #2 in the nation for receipt
of NIH research funds; and ranked #4 in the nation in U.S. News &
World Report’s most recent ranking of top research-oriented medical
schools. Supporting 1,400 fulltime faculty and 700 students, the School
of Medicine is recognized worldwide for its superior education and training
of the next generation of physician-scientists and leaders of academic
The University of Pennsylvania Health System comprises: its flagship hospital,
the Hospital of the University of Pennsylvania, consistently rated one
of the nation’s “Honor Roll” hospitals by U.S. News
& World Report; Pennsylvania Hospital, the nation's first hospital;
Penn Presbyterian Medical Center; a faculty practice plan; a primary-care
provider network; two multispecialty satellite facilities; and home health
care and hospice.