A Low-Carbohydrate as Compared with a Low-Fat Diet in Severe Obesity

Samaha, Frederick F.; Iqbal, Nayyar; Seshadri, Prakash; Chicano, Kathryn L.; Daily, Denise A.; McGrory, Joyce; Williams, Terrence T.; Williams, Marvin M. D.; Gracely, Edward J.; Stern, Linda

doi:10.1056/nejmoa022637

Cited by 1,109 publications

(858 citation statements)

References 16 publications

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“…This finding confirms in nonobese subjects the results of previous intervention trials in severely obese subjects comparing a low-CHO, high-fat and protein diet with a low-fat diet (Foster et al, 2003;Samaha et al, 2003).…”

Section: Discussionsupporting

confidence: 89%

Effects of different dietary protein intakes on body composition and vascular reactivity

et al. 2005

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Objective: To assess the effects of a diet rich in protein of animal origin in comparison to one with a protein intake of about 15% of the total daily calories on body composition and arterial function. Design: Randomized prospective study with parallel groups. Body weight (BW), blood pressure (BP), main parameters of carbohydrate and lipid metabolism, body mass composition by bioelectrical impedance analysis, forearm blood flow at rest and in the postischaemic phase by strain gauge plethysmography and flow-mediated dilation of the brachial artery by echography were measured at baseline and after 6 months of the dietary intervention. Subjects: In total, 15 clinically healthy male volunteers, regularly performing a mixed training three times weekly for 90 min. Intervention: The participants were randomly prescribed a diet with high (1.9 g/kg BW) or normal (1.3 g/kg BW) protein content. Statistical analysis: Differences between means were evaluated by the t-tests for paired or unpaired data and by one way analysis of variance. The strength of correlation between variables was investigated by bivariate Pearson correlation. Results: Serum cholesterol significantly decreased with both diets in comparison to baseline values, whereas BW was slightly but significantly reduced only by the high-protein (HP) diet. No change was detected in BP and the other metabolic parameters. Body mass composition was not significantly modified by either diet. On the other hand, postischaemic flow-mediated dilation of the brachial artery was enhanced by the sole normal protein (NP) diet, whereas no change in the forearm blood flow, both at rest and in the postischaemic phase, was detected. Conclusions: These preliminary results indicate that HP diet was found to be not useful in increasing the muscle mass in comparison to a NP intake. In contrast to this, the latter diet seems to enhance the endothelial function of the arterial vessels with a more pronounced dilatation of the lumen in response to the increase in blood flow.

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Section: Discussionsupporting

confidence: 89%

Effects of different dietary protein intakes on body composition and vascular reactivity

et al. 2005

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“…Zone) 5 diets, which have been shown in many studies of free-living individuals to be associated with impressive weight loss and improved cardiovascular risk indicators over a relatively short period of time (up to 6 months). [6][7][8][9][10][11][12][13][14][15][16] Very few data are available relating to longterm (12 months or greater) comparisons of such alternative dietary regimens 6,[17][18][19][20] and only one study has been published that compares HP, HF and the more widely recommended HC-high-fibre diet over a prolonged period. 21 We have previously reported a 6-month comparison of such diets in overweight insulin-resistant women.…”

Section: Introductionmentioning

confidence: 99%

Long-term effects of popular dietary approaches on weight loss and features of insulin resistance

et al. 2005

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Objective: High-carbohydrate (HC)-high-fibre diets are recommended for weight loss and for treating and preventing diseases such as diabetes and cardiovascular disease. We report a randomised trial comparing high-fat (HF) and high-protein (HP) diets with the conventional approach. Research design and methods: A total of 93 overweight insulin-resistant women received advice following randomisation to HF, HP or HC dietary regimes, to achieve weight loss followed by weight maintenance over 12 months. Weight, body composition and measures of carbohydrate and lipid metabolism were investigated. Results: Retention rates were 93% for HP and 75% for HC and HF. Features of the metabolic syndrome improved in all groups during the first 6 months, to a greater extent on HF and HP than an HC. During the second 6 months the HF group had increases in waist circumference (mean difference 4.4 cm (95% CI 3.0, 5.8)), fat mass (2.3 kg (1.5, 3.1)), triglycerides (0.28 mmol/l (0.09, 0.46)) and 2 h glucose (0.70 mmol/l (0.22, 1.18)). Overall there was substantial sustained improvement in waist circumference, triglycerides and insulin in the HP group and sustained but more modest changes on HC. Dietary compliance at 12 months was poor in all groups. Conclusions: HP and HC approaches appear to be appropriate options for insulin-resistant individuals. When recommending HP diets appropriate composition of dietary fat must be ensured. HC diet recommendations must include advice regarding appropriate high-fibre, low glycaemic index foods.

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“…Although there is great variability, a pattern of better responses on very low CHO is evident. It is notable that Samaha et al studied a population in which 39 % had diabetes and 43% had MetS [46]. …”

Section: Introductionmentioning

confidence: 99%

Carbohydrate restriction improves the features of Metabolic Syndrome. Metabolic Syndrome may be defined by the response to carbohydrate restriction

2005

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Metabolic Syndrome (MetS) represents a constellation of markers that indicates a predisposition to diabetes, cardiovascular disease and other pathologic states. The definition and treatment are a matter of current debate and there is not general agreement on a precise definition or, to some extent, whether the designation provides more information than the individual components. We consider here five indicators that are central to most definitions and we provide evidence from the literature that these are precisely the symptoms that respond to reduction in dietary carbohydrate (CHO). Carbohydrate restriction is one of several strategies for reducing body mass but even in the absence of weight loss or in comparison with low fat alternatives, CHO restriction is effective at ameliorating high fasting glucose and insulin, high plasma triglycerides (TAG), low HDL and high blood pressure. In addition, low fat, high CHO diets have long been known to raise TAG, lower HDL and, in the absence of weight loss, may worsen glycemic control. Thus, whereas there are numerous strategies for weight loss, a patient with high BMI and high TAG is likely to benefit most from a regimen that reduces CHO intake. Reviewing the literature, benefits of CHO restriction are seen in normal or overweight individuals, in normal patients who meet the criteria for MetS or in patients with frank diabetes. Moreover, in low fat studies that ameliorate LDL and total cholesterol, controls may do better on the symptoms of MetS. On this basis, we feel that MetS is a meaningful, useful phenomenon and may, in fact, be operationally defined as the set of markers that responds to CHO restriction. Insofar as this is an accurate characterization it is likely the result of the effect of dietary CHO on insulin metabolism. Glucose is the major insulin secretagogue and insulin resistance has been tied to the hyperinsulinemic state or the effect of such a state on lipid metabolism. The conclusion is probably not surprising but has not been explicitly stated before. The known effects of CHO-induced hypertriglyceridemia, the HDL-lowering effect of low fat, high CHO interventions and the obvious improvement in glucose and insulin from CHO restriction should have made this evident. In addition, recent studies suggest that a subset of MetS, the ratio of TAG/HDL, is a good marker for insulin resistance and risk of CVD, and this indicator is reliably reduced by CHO restriction and exacerbated by high CHO intake. Inability to make this connection in the past has probably been due to the fact that individual responses have been studied in isolation as well as to the emphasis of traditional therapeutic approaches on low fat rather than low CHO.We emphasize that MetS is not a disease but a collection of markers. Individual physicians must decide whether high LDL, or other risk factors are more important than the features of MetS in any individual case but if MetS is to be considered it should be recognized that reducing CHO will bring improvement. Response of symptoms to CHO ...

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A Low-Carbohydrate as Compared with a Low-Fat Diet in Severe Obesity

Cited by 1,109 publications

References 16 publications

Effects of different dietary protein intakes on body composition and vascular reactivity

Effects of different dietary protein intakes on body composition and vascular reactivity

Long-term effects of popular dietary approaches on weight loss and features of insulin resistance

Carbohydrate restriction improves the features of Metabolic Syndrome. Metabolic Syndrome may be defined by the response to carbohydrate restriction

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