Sample #1: From Samaha et al.'s IntroductionThe differences in health benefits between a carbohydrate-restricted diet and a calorie- and fat-restricted diet are of considerable public interest. However, there is concern that a carbohydrate-restricted diet will adverselyaffect serum lipid concentrations. Previous studies demonstrating that healthy volunteers following a low-carbohydrate diet can lose weight have involved few subjects, and few used a comparison group that followedconsensus guidelines for weight loss. The reported effects of a carbohydrate- restricted diet on risk factors for atherosclerosis have varied. We performed a study designed to test the hypothesis that severely obese subjectswith a high prevalence of diabetes or the metabolic syndrome would have a greater weight loss, without detrimental effects on risk factors for atherosclerosis, while on a carbohydrate-restricted (low-carbohydrate) diet than on a calorie- and fat-restricted (low-fat) diet.Sample #2: From Samaha et al.'s DiscussionWe found that severely obese subjects with a high prevalence of diabetes and the metabolic syndrome lost more weight in a six-month period on a carbohydrate-restricted diet than on a fat- and calorie-restricted diet. The greater weight loss in the low-carbohydrate group suggests a greater reduction in overall caloric intake, rather than a direct effect of macronutrient composition. However, the explanation for this difference is not clear. Subjects in this group may have experienced greater satiety on a diet with liberal proportions of protein and fat. However, other potential explanations include the simplicity of the diet and improved compliance related to the novelty of the diet.Sample #3: From Rabast et al.'s DiscussionThe dietary study described was performed on 21 selected obese persons who could be classified into three groups with virtually identical somatic data. Earlier studies have shown that, in reducing diets involving isocaloric exchange of carbohydrate and fat, the reduction in body weight was more marked during the diet restricted in carbohydrate and relatively rich in fat.The finding outlined in the present paper are in confirmation of these results, in that the mean weight reduction on the high-carbohydrate diet 1 was 9.5 kg, as compared to 11.4 and 12.5 kg, respectively, on the low-carbohydrate diets 2 (corn oil) and 3 (butter fat). The methodological design of the present study varied from the conditions previously described in the literature. It is felt that the conflicting results reported in the literature are causally related to the fact that the individual studies were performed over short periods and in small heterogeneous groups receiving inaccurately defined diets [for references, see Rabast et al. 25]. . . . The nitrogen excretion measured at weekly intervals was significantly higher on the low-carbohydrate diet after the 3rd and 4th week. Also the cumulatively calculated excretion of urinary potassium was found to be significantly higher on the low-carbohydrate diet during the 1st and 2nd week. Therefore the greater loss of lean tissue, especially on the corn oil diet, is to be discussed as an explanation for the more pronounced weight loss on the low-carbohydrate diet. But there were no significant differences for potassium excretion after 21 and 28 days, so the differences were not sufficiently conspicuous to afford a full explanation for the observed weight differences.Sample #4: From Johnston et al.'s DiscussionThe absence of a thermic response to the HC diet at 2.5 hours after the breakfast meal seems contradicted, butthis phenomenon has been noted by others [18]. The metabolic cost of glycogen synthesis and lipogenesis is believed to account for 55% to 65% of the thermic effect of carbohydrate ingestion [22], but only for 10% to 30% of the thermic effect of protein ingestion. The breakfast meal was consumed after an overnight, 12-hour fast; hence, it is conceivable that the ingested glucose was readily utilized by body tissues and not available for glycogen synthesis. At the lunch and dinner meals, nutrient storage would be enhanced as nutrient availability increased with repeated food ingestion.Sample #5: From Halton & Hu's Review PaperIn addition, Johnston [9] found that a diet with 30% from protein had a thermic effect of 34 kj/hour higher than a diet consisting of 15% protein. Mikkelson [14] found that a 29% pork diet increased 24-hour energy expenditure by 3.9% compared to a high carbohydrate diet with 11% protein. Leblanc [11] found that a 97% protein diet caused an oxygen consumption of 31 mL O2/kg/min while a 1% protein feeding resulted in an oxygen consumption of 17 mL O2/kg/min. However, this level of protein is unrealistic. Zed [18] found significantly increased oxygen consumption for a high protein meal compared to a high carbohydrate meal. Inboth normal and obese subjects, Swaminathan [5] found significantly higher mean metabolic rates for a high protein preload compared to high fat and high carbohydrate preloads. This evidence suggests that diets higher in protein exert a larger effect on energy expenditure than diets lower in protein. A logical question is whether or not this difference is enough to affect body weight. In the Johnston investigation [9], it was estimated that the average difference between the high and low protein diet for their subjects was 126 kj a day. For Crovetti [7], this number was 168 kj after 7 hours, and for Robinson [15] it was 251 kj after 9 hours. Sample #6: Student DraftA study on the effects of carbohydrate-restricted diets on exercise in obese persons is necessary for assessing the value of low carbohydrate restricted diets. Exercise is associated with proven health benefits, such as improved cardiovascular health, improved utilization of fatty acids, and increased insulin sensitivity, which are all important for obese individuals who are at greater risk of heart disease and diabetes (5). But, if the mechanisms that cause weight loss in low carbohydrate diets impede exercise or even make exercise a potentially dangerous activity, then the value of such diets would need to be reevaluated. Present research provides a very unclear idea of how studies on obesity and exercise would turn out. Helge's (4) study on untrained individuals indicated that a high fat diet would not be as effective as a high carbohydrate diet at improving endurance performance. Though performance may be a measure of diet