Counting Calories, Exercise and Counseling Add Up to
Best Diet in Battle Against Obesity
For senior citizens exercise may be key to offset
reduced daily activity; this diet works regardless of carbohydrate,
protein or fat content
Feb.
26, 2009 - Many popular diets emphasize either carbohydrate, protein or
fat as the best way to lose weight. But, a comparison of overweight
participants assigned to four different diets over a two-year period
showed that reducing calories achieved weight loss regardless of which
of the three nutrients was emphasized. What may be more important to
senior citizens, than younger people, is the importance of moderate exercise
in this program, since too most seniors reduce daily activity as the age.
There have been a few studies that evaluate the
effect on weight loss of diets with different compositions of those
nutrients but most lasted less than a year.
This randomized clinical trial was led by
researchers at the Harvard School of Public Health (HSPH) and Pennington
Biomedical Research Center of the Louisiana State University System. The
study, which was funded by the National Heart, Lung, and Blood Institute
(NHLBI) of the National Institutes of Health, appears in the February
26, 2009 issue of The New England Journal of Medicine.
"This is important information for physicians,
dieticians and adults, who should focus weight loss approaches on
reducing calorie intake," said Frank Sacks, professor of cardiovascular
disease prevention at HSPH and lead author of the study.
The NEJM issue includes an accompanying editorial
on the study's findings.
The trial included 811 men and women who were
randomly divided into four diet groups with different target nutrient
compositions:
● Low-fat, average protein: 20% of calories from
fat, 15% of calories from protein, 65% of calories from carbohydrate
>> The participants were diverse in age, sex
(62% women, 38% men), geography and income.
>> The diets followed heart-healthy principles,
replacing saturated with unsaturated fat and were high in whole cereal
grains, fruits and vegetables.
>> Each participant received a diet prescription
that encouraged a 750-calorie reduction per day, however none
were less than 1,200 total calories per day.
>> Participants were asked to do 90 minutes of
moderate exercise each week.
>> They recorded their daily food and drink
intake in a food diary and in a web-based program that provided
information on how closely they were meeting their dieting goals.
>> Individual counseling was provided every
eight weeks over two years and group sessions were held three out of
four weeks during the first six months and two out of four weeks from
six months to two years.
The results showed the following:
● Regardless of diet, weight loss and reduction
in waist circumference were similar.
● Participants lost an average of 13 pounds at
six months and maintained a 9-pound loss at two years.
● Weight loss primarily took place in the first
6 months; after 12 months, all groups began to slowly regain weight, a
finding consistent with other diet studies. However, the extent of
weight regain was much less, about 20%, of the average regain in
previous studies.
● Waistlines were reduced by an average of two
inches at the end of the two-year period.
● Most risk factors for cardiovascular disease
improved for dieters at six months and two years. HDL ("good")
cholesterol increased and LDL ("bad") cholesterol, triglycerides, blood
pressure and insulin decreased.
● The metabolic syndrome, a group of coronary
heart disease risk factors including high blood pressure, insulin
resistance and abdominal obesity, also decreased.
● The main finding from the trial was that diets
with varying emphases on carbohydrate, fat and protein levels all
achieved clinically meaningful weight loss and maintenance of weight
loss over a two-year period.
"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.
Another important finding was that participants who
regularly attended counseling sessions lost more weight than those who
didn't. Dieters who attended two thirds of sessions over two years lost
about 22 pounds of weight as compared to the average weight loss of 9
pounds.
"These findings suggest that continued contact with
participants to help them achieve their goals may be more important than
the macronutrient composition of their diets," said Sacks.
Support for this study was provided by the National
Heart, Lung, and Blood Institute, National Institutes of Health and NIH
General Clinical Research Center.
Harvard School of Public Health (
http://www.hsph.harvard.edu ) is dedicated to advancing the public's
health through learning, discovery, and communication. More than 400
faculty members are engaged in teaching and training the 1,000-plus
student body in a broad spectrum of disciplines crucial to the health
and well being of individuals and populations around the world. Programs
and projects range from the molecular biology of AIDS vaccines to the
epidemiology of cancer; from risk analysis to violence prevention; from
maternal and children's health to quality of care measurement; from
health care management to international health and human rights. For
more information on the school visit:
http://www.hsph.harvard.edu
Keep up with the latest news for senior citizens, baby
boomers
Feb.
26, 2009 - Many popular diets emphasize either carbohydrate, protein or
fat as the best way to lose weight. But, a comparison of overweight
participants assigned to four different diets over a two-year period
showed that reducing calories achieved weight loss regardless of which
of the three nutrients was emphasized. What may be more important to
senior citizens, than younger people, is the importance of moderate exercise
in this program, since too most seniors reduce daily activity as the age.