REDUCED CARBOHYDRATE RATIO ENHANCES METABOLIC CHANGES ASSOCIATED WITH WEIGHT
LOSS DIET

Harn J. Shiue, Carl Sather, Don K. Layman; University of
Illinois-Champaign-Urbana, 430 Bevier Hall, 905 S. Goodwin, Urbana, IL 61801


Weight loss associated with energy restriction is often associated with loss
of muscle mass as well as body fat.  This study evaluated effects of a diet
with reduced CHO/Prot ratio on changes in body composition and protein
metabolism.  Twenty-four women, 45-56 years old and 10-30% above idea were
selected to be consuming an average U.S. diet with ratios of CHO/Prot/Fat of
51/14/34.  Women were paired based on age, weight, and hormone status and
assigned to either a Protein Group (CHO/Prot ratio of 1.4) or a CHO Group
(CHO/Prot 3.7).  Diets were isocaloric (1660 kcal/d) and contained 50g
fat/d.  after 10 weeks, total weight loss for the Prot and CHO Groups were
7.53 kg and 6.96 kg, respectively.  The Prot Group lost 18% more body fat
and 27% less muscle mass (0.88 kg vs. 1/21 kg) compared to the CHO Group.
The Prot Group maintained higher levels of thyroid hormone (T3 and T4)
suggesting a higher BMR.  Fasting plasma levels of branched-chain amino
acids (BCAA) were 47% in the Prot Group.  BCAA were further elevate after
meals in the Prot Group.  These changes were associated with a 21% increase
in the post-prandial plasma alanine plus glutamine pool in the Prot Groups.
Fasting blood urea levels were not different between groups.  The meal
response was proportional to protein intake with a 43% increase in the Prot
Group and a 27% increase in the CHO Group.  These findings suggest that
weight loss on a moderate protein diet maintains thyroxine levels, increases
plasma concentration of branched-chained amino acids, and enhances changes
in body composition.  (Sponsors: NCBA and Kraft)


İFASEB* Journal 2001;15 (4 Part 1); A 301
*Federation of American Societies for Experimental Biology

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