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[A1CR]

What is the value of having various levels of carbohydrates,
protein and fat
in our diet? Having energy dissipated by having a high
protein level diet
may be the reason that weight loss occurs for such diets, is
my view.

Petzke KJ, Riese C, Klaus S.
Short-term, increasing dietary protein and fat moderately
affect energy
expenditure, substrate oxidation and uncoupling protein gene
expression in
rats.
J Nutr Biochem. 2006 Sep 13; [Epub ahead of print]
PMID: 16979329

Macronutrient composition of diets can influence body-weight
development and
energy balance. We studied the short-term effects of
high-protein (HP)
and/or high-fat (HF) diets on energy expenditure (EE) and
uncoupling protein
(UCP1-3) gene expression. Adult male rats were fed ad
libitum with diets
containing different protein-fat ratios: adequate
protein-normal fat
(AP-NF): 20% casein, 5% fat; adequate protein-high fat
(AP-HF): 20% casein,
17% fat; high protein-normal fat (HP-NF): 60% casein, 5%
fat; high
protein-high fat (HP-HF): 60% casein, 17% fat. Wheat starch
was used for
adjustment of energy content. After 4 days, overnight EE and
oxygen
consumption, as measured by indirect calorimetry, were
higher and
body-weight gain was lower in rats fed with HP diets as
compared with rats
fed diets with adequate protein content (P<.05). Exchanging
carbohydrates by
protein increased fat oxidation in HF diet fed groups. The
UCP1 mRNA
expression in brown adipose tissue was not significantly
different in HP
diet fed groups as compared with AP diet fed groups.
Expression of different
homologues of UCPs positively correlated with nighttime
oxygen consumption
and EE. Moreover, dietary protein and fat distinctly
influenced liver UCP2
and skeletal muscle UCP3 mRNA expressions. These findings
demonstrated that
a 4-day ad libitum high dietary protein exposure influences
energy balance
in rats. A function of UCPs in energy balance and
dissipating food energy
was suggested. Future experiments are focused on the
regulation of UCP gene
expression by dietary protein, which could be important for
body-weight
management.