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New research suggests a
diet higher in protein and lower in carbohydrates
than currently recommended may help people maintain desirable
body weight and overall health.
For 30 years fad diets and various nutritional
recommendations have come and gone, said Donald Layman, a
professor of nutritional sciences at the University of Illinois.
The result:
Americans take in more calories than ever, obesity is at an
all-time high, and heart disease rates equal those of the
1970s.
In addition, the Centers for Disease Control
in Atlanta recently announced a
10 percent rise in the rates of cardiac deaths among 15- to
34-year-olds between 1989 and 1996, and that just
25 percent of Americans over age 18 met basic physical activity
recommendations in the 1990s.
The situation is one of the worst public
health fiascoes we've ever seen. We may have fewer people
dying from heart disease, but that's only because our medical
recovery is better. We also are looking at an approaching
onslaught of Type 2 diabetes.
The research focused on the relationship
between exercise and nutrition, particularly what balance
of food helps maintain sufficient muscle mass so a person
can efficiently expend energy to maintain a healthy body.
For 10 weeks, 24 mid-life women, all above
ideal weight, ate 1,700-calories-a-day diets. One group ate
according to the USDA
Food Guide Pyramid - 55% carbohydrates,
15% protein (or 68 grams per day) and 30% fat.
The experimental group ate a modified
daily diet of 40% carbohydrates, 30% protein (125
grams per day) and 30% fat.
The average weight loss of all the women
was virtually identical (about 16 pounds). From there, however,
there were startling differences
for women who ate the higher protein diet.
They lost 12.3
pounds of body
fat and just 1.7
pounds of muscle
mass, a 7-to-1 ratio.
Those who stuck to the food pyramid diet
lost 10.4 pounds
of body fat and, more significantly, 3
pounds of muscle
mass - a ratio of 3.5 to 1.
The protein
diet was twice as effective.
Women eating the lower protein diet were
less capable of burning calories at the end of the study as
when they started it. Investigators believe this is the effect
of more protein, particularly the increased amount of leucine
(an essential amino acid found in protein) in the diet. Leucine's
effect has been documented in several animal studies.
The study also found higher levels of
thyroid hormones among women who ate the high protein diet,
suggesting a higher rate of metabolism. Protein-eaters also
experienced a significant decline of overall triglycerides
(fat in the blood) and a slight rise in HDL (the desirable
component of cholesterol).
Annual Meeting
Of The Federation Of American Societies For Experimental Biology
In Orlando, FL April 1, 2001
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