Re: New Study: Low Carb Diet Improves Metabolic Syndrome

x-no-archive: yes

Gantlet wrote:

Hello Will.

I would love to see a study that compares the 2 types of diets. low carb and low fat.

Really? I've posted many, which you've never read nor been interested in before, evidently:

J Clin Endocrinol Metab. 2003 Apr;88(4):1617-23. Related Articles,
Links


A randomized trial comparing a very low carbohydrate diet and a
calorie-restricted low fat diet on body weight and cardiovascular risk
factors in healthy women.

Brehm BJ, Seeley RJ, Daniels SR, D'Alessio DA.

University of Cincinnati and Children's Hospital Medical Center, Cincinnati,
Ohio 45221-0038, USA. bonnie.brehm@xxxxxx

Untested alternative weight loss diets, such as very low carbohydrate diets,
have unsubstantiated efficacy and the potential to adversely affect
cardiovascular risk factors. Therefore, we designed a randomized, controlled
trial to determine the effects of a very low carbohydrate diet on body
composition and cardiovascular risk factors. Subjects were randomized to 6
months of either an ad libitum very low carbohydrate diet or a
calorie-restricted diet with 30% of the calories as fat. Anthropometric and
metabolic measures were assessed at baseline, 3 months, and 6 months.
Fifty-three healthy, obese female volunteers (mean body mass index, 33.6 +/-
0.3 kg/m(2)) were randomized; 42 (79%) completed the trial. Women on both
diets reduced calorie consumption by comparable amounts at 3 and 6 months.
The very low carbohydrate diet group lost more weight (8.5 +/- 1.0 vs. 3.9
+/- 1.0 kg; P < 0.001) and more body fat (4.8 +/- 0.67 vs. 2.0 +/- 0.75 kg;
P < 0.01) than the low fat diet group. Mean levels of blood pressure,
lipids, fasting glucose, and insulin were within normal ranges in both
groups at baseline. Although all of these parameters improved over the
course of the study, there were no differences observed between the two diet
groups at 3 or 6 months. beta- Hydroxybutyrate increased significantly in
the very low carbohydrate group at 3 months (P = 0.001). Based on these
data, a very low carbohydrate diet is more effective than a low fat diet for
short-term weight loss and, over 6 months, is not associated with
deleterious effects on important cardiovascular risk factors in healthy
women.


N Engl J Med. 2003 May 22;348(21):2074-81. Related Articles, Links



A low-carbohydrate as compared with a low-fat diet in severe obesity.

Samaha FF, Iqbal N, Seshadri P, Chicano KL, Daily DA, McGrory J, Williams T,
Williams M, Gracely EJ, Stern L.

Philadelphia Veterans Affairs Medical Center, University of Pennsylvania
Medical Center, Philadelphia, USA. rick.samaha@xxxxxxxxxx

BACKGROUND: The effects of a carbohydrate-restricted diet on weight loss and
risk factors for atherosclerosis have been incompletely assessed. METHODS:
We randomly assigned 132 severely obese subjects (including 77 blacks and 23
women) with a mean body-mass index of 43 and a high prevalence of diabetes
(39 percent) or the metabolic syndrome (43 percent) to a
carbohydrate-restricted (low-carbohydrate) diet or a calorie- and
fat-restricted (low-fat) diet. RESULTS: Seventy-nine subjects completed the
six-month study. An analysis including all subjects, with the last
observation carried forward for those who dropped out, showed that subjects
on the low-carbohydrate diet lost more weight than those on the low-fat diet
(mean [+/-SD], -5.8+/-8.6 kg vs. -1.9+/-4.2 kg; P=0.002) and had greater
decreases in triglyceride levels (mean, -20+/-43 percent vs. -4+/-31
percent; P=0.001), irrespective of the use or nonuse of hypoglycemic or
lipid-lowering medications. Insulin sensitivity, measured only in subjects
without diabetes, also improved more among subjects on the low-carbohydrate
diet (6+/-9 percent vs. -3+/-8 percent, P=0.01). The amount of weight lost
(P<0.001) and assignment to the low-carbohydrate diet (P=0.01) were
independent predictors of improvement in triglyceride levels and insulin
sensitivity. CONCLUSIONS: Severely obese subjects with a high prevalence of
diabetes or the metabolic syndrome lost more weight during six months on a
carbohydrate-restricted diet than on a calorie- and fat-restricted diet,
with a relative improvement in insulin sensitivity and triglyceride levels,
even after adjustment for the amount of weight lost. This finding should be
interpreted with caution, given the small magnitude of overall and
between-group differences in weight loss in these markedly obese subjects
and the short duration of the study. Future studies evaluating long-term
cardiovascular outcomes are needed before a carbohydrate-restricted diet can
be endorsed. Copyright 2003 Massachusetts Medical Society


Nutr Metab. 1978;22(5):269-77. Related Articles, Links


Comparative studies in obese subjects fed carbohydrate-restricted and high
carbohydrate 1,000-calorie formula diets.

Rabast U, Kasper H, Schonborn J.

45 obese subjects were fed a high-carbohydrate, relatively low-fat, or a
low-carbohydrate, relatively high-fat 1,000-calorie (4.14MJ) formula diet.
The diet provided for an isoenergetic substitution of 170 g of carbohydrates
for 75 g of fat. Weight reduction up to day 30 was significantly higher in
the subjects on the carbohydrate-restricted diet. There were no significant
differences between the water and electrolyte balances. The mean total
weight reduction achieved on the high-carbohydrate diet was 9.8 +/- 4.5kg
with a mean daily weight loss of 298 +/- 80g, while the corresponding values
on the carbohydrate-restricted diet were 14 +/- 7.2 kg and 362 +/- 91 g/day,
respectively.

Int J Obes. 1979;3(3):201-11. Related Articles, Links


Dietetic treatment of obesity with low and high-carbohydrate diets:
comparative studies and clinical results.

Rabast U, Schonborn J, Kasper H.

In spite of numerous studies in the literature, it is still questionable as
to whether the isocaloric exchange of carbohydrate and fat, in the form of a
diet, leads to different degrees of weight loss. In comparative studies,
obese patients given a low-carbohydrate (4.14 MJ [1000 kcal]) formula diet
(diet Ia) lost 14.0 +/- 1.4 kg and those given an iso-energetic
high-carbohydrate diet (diet Ib) 9.8 +/- 0.9 kg. The degree of weight loss
was significantly different. Daily weight losses were 362 g and 298 g
respectively. Comparative studies of high and low-carbohydrate (7.83 MJ
[1900 kcal]) formula diets (diets IIa and b) with a greater number of
calories did not show any significant difference. However, there was a
greater mean weight loss with the low-carbohydrate diet (351 g/day) compared
with that under the high-carbohydrate diet (296 g/day). Evaluation of 117
patients treated with formula diets resulted in a weight loss of over 9 kg
in 102 obese patients and over 18 kg in 52 patients. The good response to
the low-carbohydrate diet was partly responsible for the successful therapy.

Ann Nutr Metab. 1981;25(6):341-9. Related Articles, Links


Loss of weight, sodium and water in obese persons consuming a high- or
low-carbohydrate diet.

Rabast U, Vornberger KH, Ehl M.

Isocaloric 5.61 mJ (1,340 kcal) formula diets involving the isocaloric
exchange of fat and carbohydrate were fed to 21 obese persons selected for
sex, height, and weight before the start of the treatment and distributed
over three groups. The weight loss observed during the
carbohydrate-restricted diets was significantly greater than during the
high-carbohydrate diet. After 28 days of treatment the weight loss recorded
on the high-carbohydrate diet was 9.5 +/- 0.7 kg, as compared to 11.4 +/-
0.7 kg (p less than 0.05) on the corn oil-containing diet and 12.5 +/- 0.9
kg (p less than 0.01) on the butter-fat-containing diet. The weight loss
achieved was not dependent on the type of fat administered (saturated vs.
polyunsaturated). When calculated cumulatively, sodium excretion during the
first 7 days was significantly greater on the low-carbohydrate diet, whereas
after 28 days the total amount of sodium excreted was highest on the
high-carbohydrate diet. Potassium excretion during the low-carbohydrate
diets was significantly greater for as long as 14 days, but at the end of
the experimental period the observed differences no longer attained
statistical significance. At no time did the intake and loss of fluid and
the balances calculated therefrom show significant differences. From the
findings obtained it appears that the alterations in the water and
electrolyte balance observed during the low-carbohydrate diets are
reversible phenomena and should thus not be regarded as causal agents of the
different weight reduction.






J Pediatr. 2003 Mar;142(3):253-8. Related Articles, Links


Comment in:
J Pediatr. 2003 Mar;142(3):225-7.

Effects of a low-carbohydrate diet on weight loss and cardiovascular risk factor in overweight adolescents.

Sondike SB, Copperman N, Jacobson MS.

Division of Adolescent Medicine, Schneider Children's Hospital, New Hyde Park, New York 10128, USA.

OBJECTIVES: To compare the effects of a low-carbohydrate (LC) diet with those of a low-fat (LF) diet on weight loss and serum lipids in overweight adolescents. DESIGN: A randomized, controlled 12-week trial. SETTING: Atherosclerosis prevention referral center. METHODS: Random, nonblinded assignment of participants referred for weight management. The study group (LC) (n = 16) was instructed to consume <20 g of carbohydrate per day for 2 weeks, then <40 g/day for 10 weeks, and to eat LC foods according to hunger. The control group (LF) (n = 14) was instructed to consume <30% of energy from fat. Diet composition and weight were monitored and recorded every 2 weeks. Serum lipid profiles were obtained at the start of the study and after 12 weeks. RESULTS: The LC group lost more weight (mean, 9.9 +/- 9.3 kg vs 4.1 +/- 4.9 kg, P <.05) and had improvement in non-HDL cholesterol levels (P <.05). There was improvement in LDL cholesterol levels (P <.05) in the LF group but not in the LC group. There were no adverse effects on the lipid profiles of participants in either group. CONCLUSIONS: The LC diet appears to be an effective method for short-term weight loss in overweight adolescents and does not harm the lipid profile.

Publication Types:
Clinical Trial
Randomized Controlled Trial

PMID: 12640371 [PubMed - indexed for MEDLINE

http://www.ajcn.org/cgi/content/full/80/5/1102

Saturated fat prevents coronary artery disease? An American paradox1,2
Robert H Knopp and Barbara M Retzlaff
1 From the Northwest Lipid Research Clinic, University of Washington
School of Medicine, Seattle

2 Address reprint requests to RH Knopp, Northwest Lipid Research
Clinic, University of Washington, School of Medicine, 325 9th Avenue,
Seattle, WA 98104. E-mail: rhknopp@xxxxxxxxxxxxxxxxx

See corresponding article on page 1175.


It is an article of faith that saturated fat raises LDL cholesterol and
accelerates coronary artery disease, whereas unsaturated fatty acids
have the opposite effect (1, 2). One of the earliest and most
convincing studies of the better efficacy of unsaturated than of
saturated fat in reducing cholesterol and heart disease is the Finnish
Mental Hospital Study conducted in the 12 y between 1959 and 1971. In
this study, the usual high-saturated-fat institutional diet was
compared with an equally high-fat diet in which the saturated fat in
dairy products was replaced with soybean oil and soft margarine and
polyunsaturated fats were used in cooking. Each diet was provided for 6
y and then the alternate diet was provided for the next 6 y (3). After
a comparison of the effects of the 2 diets in both men and women, the
incidence of coronary artery disease was lower by 50% and 65% after the
consumption of polyunsaturated fat in the 2 hospitals.

In this issue of the Journal, Mozaffarian et al (4) report the opposite
association. They found that a higher saturated fat intake is
associated with less progression of coronary artery disease according
to quantitative angiography. How can this paradox be explained? In
food-frequency questionnaires, saturated fat intake is more precisely
estimated than is total fat. If saturated fat is more precisely
estimated, it will associate more strongly in statistical analyses with
the outcome variable, even though other variables-such as total fat
or carbohydrate-could be more relevant physiologically. We believe
that these possibilities deserve a closer look.

Unlike the diet used in the Finnish Mental Hospital Study, the diet
described by Mozaffarian et al was low in fat, averaging 25% of energy.
The study subjects were women with coronary artery disease: most were
hypertensive, many had diabetes (19-31%), their body mass index
(kg/m2) ranged from 29 to 30, and their lipid profile indicated
combined hyperlipidemia (triacylglycerol concentration: 200 mg/dL;
HDL-cholesterol concentration: 40-50 mg/dL; above-average LDL
concentration: 135-141 mg/dL); these characteristics are consistent
with the metabolic syndrome. In addition, two-thirds of these women
were taking sex hormones. The importance of each of these points is
addressed below.

What are the effects of a low-fat, high-carbohydrate diet in comparison
with those of a higher-fat, lower-carbohydrate diet? The response
differs by the 2 main types of hyperlipidemia: simple
hypercholesterolemia and combined hyperlipidemia. In our studies of
simple hypercholesterolemia in men, a fat intake <25% of energy and a
carbohydrate intake >60% of energy was associated with a sustained
increase in triacylglycerol of 40%, a decrease in HDL cholesterol of
3.5%, and no further decrease in LDL in comparison with higher fat
intakes (5). In contrast, a low-fat diet in persons with combined
hyperlipidemia caused no worsening of triacylglycerol or HDL, but
intakes of fat >40% of energy and of carbohydrate <45% of energy for 2
y were associated with a lower triacylglycerol concentration at a
stable weight (6). In the subjects of Mozaffarian et al, a greater
saturated fat intake paralleled a total fat intake, which ranged from
18% to 32% of energy in the first to fourth quartiles. Modest favorable
trends in triacylglycerol and HDL-cholesterol concentrations were
observed with higher fat intakes.

Triacylglycerol and HDL-cholesterol concentrations are stronger
predictors of coronary artery disease in women, whereas the
LDL-cholesterol concentration is a stronger predictor in men (7).
Because VLDL triacylglycerol secretion and removal rates in healthy
women are double those of men (8), conditions impairing lipoprotein
removal would be expected to exaggerate the hyperlipidemic response in
women as compared with that in men (9). This sex difference is seen
with the development of diabetes. The increment in lipids is greater in
women than in men and is associated with a greater increment in
coronary artery disease risk in women than in men (9). Similarly, the
development of insulin resistance and obesity is associated with a
greater lipoprotein increment in women than in men (10). The
exaggerated decreases in HDL- and HDL2-cholesterol concentrations
observed with the consumption of a low-fat Step II diet in women but
not in men appear to be another facet of this effect (11).

The failure of female sex hormones to prevent coronary artery disease
has been a great disappointment (9). This effect might also be due to
an estrogen-induced increase in lipoprotein entry against a fixed or
impaired rate of lipoprotein removal, as might be expected in women
with the metabolic syndrome and coronary artery disease.

Would saturated fat still be bad for anyone? Not necessarily. The
effect of saturated fat and cholesterol ingestion in the form of 4
eggs/d for 1 mo in obese, insulin-resistant subjects is 33% of that
seen in lean, insulin-sensitive subjects, likely because of diminished
cholesterol absorption (12). Thus, the classic effects of saturated fat
as compared with those of unsaturated fat seen in the Finnish Mental
Hospital Study are likely blunted in the subjects of Mozaffarian et al,
whereas the effects of low fat and high carbohydrate intakes on
triacylglycerol and HDL-cholesterol concentrations appear to be
exaggerated by the interactions of female sex, exogenous sex hormones,
and the metabolic syndrome. A major effect on cardiovascular disease
risk would be the result of hypertriglyceridemia and low
HDL-cholesterol concentrations, which are attenuated by an increase in
saturated fat intake itself or in total fat intake, for which saturated
fat is a more statistically stable surrogate (4).

In conclusion, the hypothesis-generating report of Mozaffarian et al
draws attention to the different effects of diet on lipoprotein
physiology and cardiovascular disease risk. These effects include the
paradox that a high-fat, high-saturated fat diet is associated with
diminished coronary artery disease progression in women with the
metabolic syndrome, a condition that is epidemic in the United States.
This paradox presents a challenge to differentiate the effects of
dietary fat on lipoproteins and cardiovascular disease risk in men and
women, in the different lipid disorders, and in the metabolic syndrome.


REFERENCES


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Miettinen M, Turpeinen O, Karvonen MJ, Elosuo R, Paavilainen E. Effect
of cholesterol-lowering diet on mortality from coronary heart-disease
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progression of coronary atherosclerosis in postmenopausal women. Am J
Clin Nutr 2004;80:1175-84.[Abstract/Free Full Text]
Knopp RH, Walden CE, Retzlaff BM, et al. Long-term cholesterol-lowering
effects of 4 fat-restricted diets in hypercholesterolemic and combined
hyperlipidemic men. The Dietary Alternatives Study. JAMA
1997;278:1509-15.[Abstract]
Retzlaff BM, Walden CE, Dowdy AA, McCann BS, Anderson KV, Knopp RH.
Changes in plasma triacylglycerol concentrations among free-living
hyperlipidemic men adopting different carbohydrate intakes over 2 y:
the Dietary Alternatives Study. Am J Clin Nutr
1995;62:988-95.[Abstract]
Knopp RH, Zhu X, Bonet B. Effects of estrogens on lipoprotein
metabolism and cardiovascular disease in women. Atherosclerosis
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Mittendorfer B, Patterson BW, Klein S. Effect of sex and obesity on
basal VLDL-triacylglycerol kinetics. Am J Clin Nutr
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Barrett-Connor E, Giardina EG, Gitt AK, Gudat U, Steinberg HO, Tschoepe
D. Women and heart disease: the role of diabetes and hyperglycemia.
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Aikawa K, Retzlaff B, Fish B, et al. Dyslipidemia of insulin resistance
and obesity: gender differences. Circulation 2002;106(suppl 2):II-75
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Walden CE, Retzlaff BM, Buck BL, Wallick S, McCann BS, Knopp RH.
Differential effect of the National Cholesterol Education Program
(NCEP) Step II diet on HDL cholesterol, its subfractions, and
apoprotein A-I levels in hypercholesterolemic women and men after 1
year: the beFIT Study. Arterioscler Thromb Vasc Biol
2000;20:1580-7.[Abstract/Free Full Text]
Knopp RH, Retzlaff B, Fish B, et al. Effects of insulin resistance and
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Lipids. 1994 Feb;29(2):129-38. Related Articles, Links

The effect of dietary fat level and quality on plasma lipoprotein
lipids and plasma fatty acids in normocholesterolemic subjects.

Sanders K, Johnson L, O'Dea K, Sinclair AJ.

School of Nutrition and Public Health, Deakin University, Geelong,
Victoria, Australia.

This study examined the effect on the plasma lipids and plasma
phospholipid and cholesteryl ester fatty acids of changing froma
typical western diet to a very low fat (VLF) vegetarian diet
containing one egg/day. The effect of the addition of saturated,
monounsaturated or polyunsaturated fat (PUFA) to the VLF diet was also
examined. Three groups of 10 subjects (6 women, 4 men) were fed the
VLF diet (10% energy as fat) for two weeks, and then in the next two
weeks the dietary fat in each group was increased by 10% energy/week
using butter, olive oil or safflower oil. The fat replaced dietary
carbohydrate. The VLF diet reduced both the low density lipoprotein
(LDL)- and high density lipoprotein (HDL)-cholesterol levels; addition
of the monounsaturated fats and PUFA increased the HDL-cholesterol
levels, whereas butter increased the cholesterol levels in both the
LDL- and HDL-fractions. The VLF diet led to significant reductions in
the proportion of linoleic acid (18:2 omega 6) and eicosapentaenoic
acid (20:5 omega 3) and to increases in palmitoleic (16:1),
eicosatrienoic (20:3 omega 6) and arachidonic acids (20:4 omega 6) in
both phospholipids and cholesteryl esters. Addition of butter reversed
the changes seen on the VLF diet, with the exception of 16:1, which
remained elevated. Addition of olive oil resulted in a significant
rise in the proportion of 18:1 and significant decreases in all omega
3 PUFA except 22:6 compared with the usual diet. The addition of
safflower oil resulted in significant increases in 18:2 and 20:4 omega
6 and significant decreases in 18:1, 20:5 omega 3 and 22:5 omega 3.
These results indicate that the reduction of saturated fat content of
the diet (< 6% dietary energy), either by reducing the total fat
content of the diet or by exchanging saturated fat with unsaturated
fat, reduced the total plasma cholesterol levels by approximately 12%
in normocholesterolemic subjects. Although the VLF vegetarian diet
reduced both LDL- and HDL-cholesterol levels, the long-term effects of
VLF diets are unlikely to be deleterious since populations which
habitually consume these diets have low rates of coronary heart
disease. The addition of safflower oil or olive oil to a VLF diet
produced favorable changes in the lipoprotein lipid profile compared
with the addition of butter. The VLF diets and diets rich in butter,
olive oil or safflower oil had different effects on the 20 carbon
eicosanoid precursor fatty acids in the plasma.(ABSTRACT TRUNCATED AT
400 WORDS)

PMID: 8152346 [PubMed - indexed for MEDLINE]
Lipids 1995 Nov;30(11):969-76 Related Articles, Links

Low-fat diets do not lower plasma cholesterol levels in healthy men compared to high-fat diets with similar fatty acid composition at constant caloric intake.

Nelson GJ, Schmidt PC, Kelley DS.

Western Human Nutrition Research Center, USDA, ARS, Presidio of San Francisco, California 94129, USA.

In most studies reporting the effects of high-fat (HF) and low-fat (LF) diets on human plasma fatty acids (FA) and lipoprotein levels, the design involved adding to the diet an oil that had an FA composition (FAC) very different from the FAC of the control diet. Thus, it is difficult to determine if simply reducing the fat content of the diet without changing the dietary FAC changes the tissue FAC or alters plasma lipid levels. In this study, we fed diets that contained either 22 or 39% of calories from fat, but had no differences in their FAC, for 50 d to a group (n = 11) of healthy men (20-35 y). Thus, the polyunsaturated/saturated ratios (1.0) of the diets were identical as were the n-3/n-6 ratio and the monounsaturated-to-total fat ratios. The diets contained (wt% of total fat) approximately 28% saturated FA, 33% monounsaturated cis-FA, 6% monounsaturated trans-FA, 22% n-6 polyunsaturated FA, and 7% n-3 polyunsaturated FA, and 4% other minor FA. The diets consisted of natural foods and were formulated to contain 16 en% protein, either 45 or 62 en% carbohydrate (CHO) and at least the recommended daily allowance for all micronutrients. Both diets contained 360 mg of cholesterol per day. All subjects were given the HF diet for 20 d, and then six were placed on the LF and the other five remained on the HF diet for 50 d. The two groups were crossed-over for the remaining 50 d of the study. The subjects' baseline total cholesterol level was 173 mg/dl, after 50 d on the HF diet it was 177 mg/dl and after 50 d on the LF diet, 173 mg/dl. The differences were not significant, and there were no significant changes in either the LDL or HDL cholesterol levels with either diet. Triglyceride levels, and consequently very low density lipoprotein levels, rose significantly on the LF, higher CHO diet compared to the levels found in the subjects on the HF diet (91.5 and 66.4 mg/dl respectively, P < 0.002). The linoleic acid content of the plasma, platelets, and red blood cells was significantly (P < 0.05) reduced in the LF diet compared to HF diet, without any obvious physiological effects. Hence, many earlier observations indicating reductions in plasma lipid levels when people are on LF diets may be due to changes in the FAC of the diet, not the reduction in fat calories.

PMID: 8569436 [PubMed - indexed for MEDLINE]

Int J Obes Relat Metab Disord 1996 Dec;20(12):1067-72 Related Articles, Links

Weight-loss with low or high carbohydrate diet?

Golay A, Eigenheer C, Morel Y, Kujawski P, Lehmann T, de Tonnac N.

Department of Internal Medicine, University Hospital Geneva.

OBJECTIVE: With obesity being recognized as an important cardiovascular risk factor, it is important to determine the optimal hypocaloric diet for decreasing that risk. The goal of this study was to compare the effects of two hypocaloric diets of similar caloric value, but differing in carbohydrate content (25% and 45%). SUBJECTS: Sixty-eight out-patients were followed for 12 w. DESIGN: The patients were assigned to one of two groups that received either a low (25% CHO, n = 31) or a high (45% CHO, n = 37) carbohydrate hypocaloric diet (5.0 MJ/d, 1200 Kcal/d). RESULTS: After 12 w, the mean weight loss was similar and did not differ significantly between the two groups: 10.2 +/- 0.7 kg (25% CHO) and 8.6 +/- 0.8 kg (45% CHO). Furthermore, loss of adipose tissue was similar, 8.1 +/- 0.5 kg (25% CHO) and 7.1 +/- 0.7 kg (45% CHO). Despite a high protein intake (1.4 g/kg/ideal body weight) there was loss of lean body mass: 2.2 +/- 0.4 kg (25% CHO) and 1.4 +/- 0.3 kg (45% CHO). The waist/hip ratio diminished significantly (P < 0.001) and identically in both groups. The fasting blood glucose (even though normal, along with cholesterol and triglyceride concentrations, were significantly decreased after weight loss. The fasting blood insulin which was mildly elevated before weight loss decreased more markedly with the 25% CHO diet compared to the 45% CHO diet (P < 0.003). The glucose/insulin ratio improved significantly (P < 0.05) after weight loss with both diets (0.17 +/- 0.04 mmol/mU (25% CHO) vs 0.10 +/- 0.03 mmol/mU (45% CHO). CONCLUSIONS: Neither diet offered a significant advantage when comparing weight loss or other, metabolic parameters over a 12 w period. However, considering the greater improvement of fasting blood insulin, the glucose/insulin ratio and blood triglyceride, the low carbohydrate diet (25%) could be more favourable in the long-term. The improvement of fasting blood insulin could be explained by the differences in monounsaturated fat composition in the low carbohydrate diet.

PMID: 8968851 [PubMed - indexed for MEDLINE]

High-Protein Beats High-Carbohydrate for Weight Loss in Low-Fat Diets
A DGReview of :"Postprandial Thermogenesis Is Increased 100% on a High-Protein,
Low-Fat Diet versus a High Carbohydrate, Low-Fat Diet in Healthy, Young Women"
Journal of the American College of Nutrition

02/26/2002
By David Ball


High-protein, low-fat diets are more efficacious for weight loss than
high-carbohydrate, low-fat diets.

The result could be explained by the added energy-cost associated with the
former, say researchers at Arizona State University East, United States, who
compared both diets for the acute, energy-cost of meal-induced thermogenesis.

Ten campus female students, aged 19-22 years, took part in the randomised,
cross-over designed study. These healthy, non-smoking volunteers consumed the
high-protein and the high-carbohydrate diets for one day each.

Testing was separated by a 28 or 56 day interval. Control diets were consumed
for two days before each test day when resting energy expenditure, non-protein
respiratory quotient and body temperature were measured. Urine and fasting
blood samples were collected.

Measurements taken after a 10 hour fast and at 2.5-hour post breakfast, lunch
and dinner showed that postprandial thermogenesis averaged about twofold higher
on the high-protein against the high-carbohydrate diet.

After breakfast and dinner the differences were significant (p<0.05) and after
the dinner meal body temperature was slightly higher on the high protein diet
(p=0.08). There was no difference between diets in changes in the respiratory
quotient post meals and none in 24 hour glomerular filtration rates.

Nitrogen balance on the high protein diet was found to be significantly greater
than the high-carbohydrate diet (7.6±0.9 and -0.4±0.5 gN/day, p<0.05). Fasting
plasma urea nitrogen concentrations at 24 hour post intervention were raised on
the high-protein versus the high-carbohydrate diet (13.9±0.9 and 11.2±1.0 mg/dL
respectively, p<0.05).

Journal of the American College of Nutrition 02:21:pg.55. "Postprandial
Thermogenesis Is Increased 100% on a High-Protein, Low-Fat Diet versus a High
Carbohydrate, Low-Fat Diet in Healthy, Young Women"



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