Heart-healthy, Low-cal Diets Promote
Weight Loss Regardless Of Fat, Protein And Carb 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.
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 Dr. Elizabeth G. Nabel, 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. Dietswere 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 risk."
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
"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
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. Click here
for the general guidelines.
For more information on the
NIH/National Heart, Lung and Blood Institute, visit www.nhlbi.nih.gov.