Study reignites low-carb high-protein debate

Here's another interesting study that backs what I've been
writing about concerning a low carb diet.

When combining a low carb diet along with a higher
protein intake it helps with weight loss. I also believe that
the higher protein intake (when combined with a good
weight training program!) will support muscle growth.

And remember, muscle's an active tissue!

Study reignites low-carb high-protein debate:
"A recent study props up the principle of low-carb high-
protein dieting – giving the low carb fad diets that pushed
meat consumption, such as the once fashionable Atkins diet,
one last laugh."

The recent findings by scientists at University College London
(UCL) could vindicate, at least partially, these recent dieting
fads as they have illustrated more clearly how high-protein
diets can be effective in combating obesity.

The study, published in the September issue of Cell
Metabolism, set out to investigate how increased dietary
protein increases satiety, hypothezing that gut hormones
could mediate the differential satiation produced by protein,
fat, and carbohydrates.

The Medical Research Council team of researchers, led by
Dr. Rachel Batterham, linked high protein diets to higher
levels of the gut hormone known as PYY. Their work suggests
PYY is an important appetite suppressor that sends signals
to the brain leading to a feeling of fullness.

"In summary, our current studies have established the
physiological role of PYY as a regulator of energy homeostasis
and demonstrated that it mediates the satiating and weight-
reducing effects of dietary protein," wrote the study authors.

Ten healthy normal-weight and ten obese male volunteers
were given an isocaloric meal, high in one macronutrient -
protein, fat or carbohydrate - and researchers then analyized
their blood samples.

The high-protein diet resulted in the greatest reduction in
hunger in both normal and obese participants. The high-
protein meal resulted in the largest increase in both total
plasma PYY and integrated PYY levels in both groups,
although post-meal levels were lower in obese subjects.

"These findings suggested that PYY could mediate the
satiating effects of protein in humans," explained the
authors. "We therefore developed a rodent experimental
model in which to investigate this possibility."

As such, genetically modified mice that lacked the PYY
hormone were then created. The PYY deficient mice ate
more than regular mice and, as a result, became obese.

The mice were fed high-fat normal-protein, high-fat
high-protein, low-fat normal-protein or low-fat high-protein
diets.

The researchers found the PYY null mice were hyperphagic
and developed marked obesity but were hypersensitive to
exogenous PYY.

They then administered PYY to these mice. The mice's
food intake subsequently decreased to normal levels as
did their weight. When they no longer received PYY, the
amount they ate went up again at the same time as their
weight.

"Chronic treatment with PYY reverses their obesity
phenotype," the authors commented on the obese mice.
"These findings provide compelling evidence that PYY is
a physiologically relevant regulator of food intake and body
weight."

The findings could help explain the current obesity epidemic
plaguing North America and Europe. Statistics show diets
have shifted from being protein-rich to carbohydrate-rich,
according to the study, and carbohydrates do not curb
appetite in the same way protein does, resulting in people
eating more to compensate.

Currently, the average Western diet derives 49 per cent of
energy from carbohydrates, 35 per cent from fat, and 16 per
cent from protein, cites the study.

"This research suggests that an increase in the protein content
of the diet may help tackle obesity," said Dr.Batterham.
"However, large scale clinical trials are needed before high-
protein low-fat diets can be recommended."

Study reference:
Rachel L. Batterham et al. "Critical role for peptide YY in
protein-mediated satiation and body-weight regulation."
Cell Metabolism. Vol 4: 223-233, September 2006.






low carb diet