|Heart-Healthy, Reduced-Calorie Diets Promote
Long-term Weight Loss
Regardless of Fat, Protein, and Carbohydrate Content
Heart-healthy diets that reduce calorie intake — regardless of
differing proportions of fat, protein, or carbohydrate — can
help overweight and obese adults achieve and maintain weight loss,
according to a study funded by the National Heart, Lung, and Blood
Institute (NHLBI) of the National Institutes of Health, and published
Feb. 26, 2009, in the New England Journal of Medicine.
Researchers from the Preventing Overweight Using Novel Dietary
Strategies (POUNDS LOST) study found similar weight loss after
six months and two years among participants assigned to four diets
that differed in their proportions of these three major nutrients.
The diets were low or high in total fat (20 or 40 percent of calories)
with average or high protein (15 or 25 percent of calories). Carbohydrate
content ranged from 35 to 65 percent of calories. The diets all
used the same calorie reduction goals and were heart-healthy — low
in saturated fat and cholesterol while high in dietary fiber.
On average, participants lost 13 pounds at six months and maintained
a 9 pound loss at two years. Participants also reduced their waistlines
by 1 to 3 inches by the end of the study. Craving, fullness, hunger,
and diet satisfaction were all similar across the four diets.
"These results show that, as long as people follow a heart-healthy,
reduced-calorie diet, there is more than one nutritional approach
to achieving and maintaining a healthy weight," said Elizabeth
G. Nabel, M.D., director, NHLBI. "This provides people who need
to lose weight with the flexibility to choose an approach that
they’re most likely to sustain — one that is most suited
to their personal preferences and health needs."
In the POUNDS LOST study, 811 overweight and obese adults aged
30 to 70 were assigned to one of four diets, and asked to record
their food intake in a diary or an online tool that showed how
intake compared with goals. Group diet counseling sessions were
held at least twice per month throughout the two years of the study,
and individual sessions were held every eight weeks. Participants
were given personalized calorie goals, ranging from 1,200 to 2,400
calories per day, which reduced their overall caloric intake as
compared with their daily energy requirement. All participants
were asked to do moderate-intensity physical activity, such as
brisk walking, for at least 90 minutes per week. Study participants
were diverse in gender and ethnicity, with 38 percent men and 22
percent representing minorities. Participants did not have diabetes
or severe heart disease but could have had other risk factors,
such as high blood pressure or high cholesterol.
Overweight is defined by having a body mass index (BMI) — a
calculation of the relationship between weight and height — greater
than 25 and less than 30. Those with a BMI of 30 or higher are
considered to be obese. Sixty-six percent of American adults are
overweight and of those, 32 percent are obese, according to the
Centers for Disease Control and Prevention.
Research was conducted in Boston at Harvard University School
of Public Health and at the Pennington Biomedical Research Center
of Louisiana State University in Baton Rouge, La. Diets were adapted
during sessions to the diverse cuisines from these two regions
of the country.
"We were encouraged that, in addition to achieving and maintaining
weight loss, study participants experienced other positive health
changes as well," said Catherine M. Loria, Ph.D., a nutritional
epidemiologist at NHLBI and co-author of the study. "The findings
emphasize the importance of weight loss in reducing heart disease
All diets improved risk factors for cardiovascular disease at
both six months and two years in ways consistent with previous
studies. Improved risk factors include reduced levels of triglycerides,
LDL (bad) cholesterol, lowered blood pressure, and increased HDL
(good) cholesterol. All diets decreased the presence of metabolic
syndrome, a cluster of related conditions, overweight, high triglycerides,
high blood sugar, high blood pressure, and low HDL cholesterol,
which increases heart disease risk.
Previous studies have shown that a loss of 5 to10 percent of body
weight will help reduce risk factors for heart disease and other
medical conditions. In this study, 15 percent of patients achieved
a 10 percent weight loss after two years.
"This new information should focus weight loss approaches
on reducing calorie intake rather than any particular proportions
of fat, protein or carbohydrate. This is important information
for health professionals who prescribe weight loss for their patients,
and for adults who are seeking ways to sustain a healthful eating
pattern," said Frank M. Sacks, M.D., principal investigator
of POUNDS LOST and Professor of Cardiovascular Disease Prevention
in the Nutrition Department at the Harvard School of Public Health.
The target nutrient compositions of the four diets were:
- Low-fat, average protein: 20 percent fat, 15 percent protein,
65 percent carbohydrate
- Low-fat, high protein: 20 percent fat, 25 percent protein,
55 percent carbohydrate
- High-fat, average protein: 40 percent fat, 15 percent protein,
45 percent carbohydrate
- High-fat, high-protein: 40 percent fat, 25 percent protein,
35 percent carbohydrate
While the design of the POUNDS LOST study called for physical
activity targets to be set at 90 minutes per week, many people
need more physical activity in order to achieve their weight loss
goals. For more information, see the 2008 Physical Activity Guidelines
for Americans at www.health.gov/paguidelines.
Further information about this trial (NCT00072995) can be found
Part of the National Institutes of Health, the National Heart, Lung,
and Blood Institute (NHLBI) plans, conducts, and supports research
related to the causes, prevention, diagnosis, and treatment of heart,
blood vessel, lung, and blood diseases; and sleep disorders. The
Institute also administers national health education campaigns on
women and heart disease, healthy weight for children, and other topics.
NHLBI press releases and other materials are available online at www.nhlbi.nih.gov.
The National Institutes of Health (NIH) — The Nation's
Medical Research Agency — includes 27 Institutes and
Centers and is a component of the U.S. Department of Health and
Human Services. It is the primary federal agency for conducting
and supporting basic, clinical and translational medical research,
and it investigates the causes, treatments, and cures for both
common and rare diseases. For more information about NIH and
its programs, visit www.nih.gov.