Here is an excerpt from a recent 'Food for Thought' publication by University of Illinois -

Is one diet as good as another? Study says no and tells why
if you want to lose weight, any diet
will do, right? No, not if you want
to lose fat instead of muscle. Not if
you want to lower your triglyceride levels
and be less likely to develop diabetes and
heart disease. Not if you want to avoid cravings
that tempt you to cheat on your diet.
And not if you want to keep your lost weight
off long-term.
“Our latest study shows you have a
better chance of achieving all these goals if
you follow a diet that is moderately high in
protein and lower in carbohydrates,”said
Donald Layman, a professor emeritus of
nutrition. The research was published in the
Journal of Nutrition.
Layman’s study followed the weight-loss
efforts of 130 persons at the U of I and Penn
State University during 4 months of active
weight loss and 8 months of maintenance.
Two previous studies had looked at short term
weight loss; this one was designed to
look at long-term effects, he said.

The participants were divided between
two eating plans. The plans were equal in
calories, but half the group followed a moderate-
protein diet (40 percent carbohydrates,
30 percent protein, 30 percent fat)
while the other half followed a diet based on
USDA’s food-guide pyramid (55 percent carbohydrates,
15 percent protein, 30 percent
fat).
“Persons in the first group ate twice the
amount of protein as the second group,”said
Layman.
And the difference in protein made all
the difference in improved body composition
and body lipids, he said.
Although the amount of weight lost by
all participants was similar, at 4 months
those in the moderate-protein group had
lost 22 percent more body fat. At 12 months,
that advantage had grown to 38 percent.
“The additional protein helped dieters
preserve muscle. That’s important for longterm
weight loss because muscle burns calories—
if you lose muscle, and you used to be
able to consume 2,000 calories without gaining
weight, you’ll find that now you can only
eat, say, 1,800 calories without weight gain,”
Layman said.
What were the effects on lipids? Although
at 4 months the food-guide pyramid
diet appeared to be more effective in lowering
LDL (“bad”) and total cholesterol levels,
at 12 months that group’s LDL cholesterol
came back up, showing the two diets to be
equally effective, Layman said.
“This is the first study to show that shortterm
changes in LDL cholesterol are not
maintained with long-term weight loss.
Most scientists believe that high cholesterol
is more a factor of genetics than of diet,”he
said.
But the moderate-protein diet had by far
the bigger effect on lowering triglycerides,
and that lasted as long as individuals remained
on the diet.
“Of the two types of lipid problems, high
triglycerides pose a greater risk for heart disease.
Approximately twice as many people
have high triglycerides, and people with this
condition are approximately four times more
likely to die from heart disease,”Layman said.
To ensure compliance, participants met
every week for weigh-ins and nutrition instruction.“
We taught participants how to
follow their diet, how to shop for groceries,
and how to prepare the meals. They also
measured everything they ate three days a
week.”

“Studies that report there is no difference
among diets also report that subjects
were not carefully following the diets,”said
Layman.“It’s very important to realize the
difference between diet compliance and
diet effectiveness.”
The moderate-protein diet was easier to
follow and maintain long-term, with 64 percent
of those dieters completing the study
compared to 45 percent of dieters eating the
high-carbohydrate diet, Layman said.
“Subjects on the moderate-protein diet
reported that they weren’t as interested in
snacks or desserts, and they didn’t have food
cravings.When you eat protein, you feel full
longer.”
Average weight loss for the moderateprotein
group was 23 percent higher, with
31 percent of“completers”losing more of
than 10 percent of their initial body
weight compared with 21 percent of the
food-pyramid group.