Carbohydrate for weight and metabolic control: Where do we stand?
ABSTRACT Changes in lifestyle are considered to play an important role in the etiology of obesity and type 2 diabetes, and improvements in diet and physical activity are the first-choice treatment for these metabolic diseases. Since the dietary recommendations of almost 40 y ago that fat should be decreased and that carbohydrate should be increased, recommendations for a healthy diet, except for minor amendments, have not changed that much. It is generally considered that caloric restriction is more important than changes in the macronutrient composition of the diet for weight loss and body weight control. Although this is true, there is increasing evidence that changes in the macronutrient composition of the diet (decreasing carbohydrate and increasing unsaturated fats and/or protein) play a role that facilitates weight loss, increases insulin sensitivity and glucose tolerance, and improves cardiovascular risk factors, such as blood pressure, blood lipid profile, and inflammatory markers, often independent of weight loss. Low-carbohydrate diets, whether they be high in unsaturated fats and/or protein, are not recommended by the American Diabetes Association; however, despite this the Joslin Diabetes Center currently advocates a diet composition of approximately 40% carbohydrate, 30% fat, and 30% protein energy for overweight and obese adults with type 2 diabetes or prediabetes or those at high risk of developing type 2 diabetes. Hopefully, future studies will indicate whether diets with a more equilibrated macronutrient composition than presently recommended are more appropriate for body weight and metabolic control.
- SourceAvailable from: Shangyu Hong
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- "In addition to central nervous system effects, low-carbohydrate ketogenic diets are also considered as a potential alternative to low-fat, high-carbohydrate dieting in preventing obesity and its metabolic complications . Human trials have shown that the weight loss achieved on low carbohydrate diets is equivalent to caloric restriction on a high carbohydrate diet and may also confer cardiovascular benefits     . "
ABSTRACT: Low-carbohydrate ketogenic diets are commonly used as weight loss alternatives to low-fat diets, however the physiological and molecular adaptations to these diets are not completely understood. It is assumed that the metabolic phenotype of the ketogenic diet (KD) is caused by the absence of carbohydrate and high fat content, however in rodents the protein content of KD affects weight gain and ketosis. In this study we examined the role of methionine and choline in mediating the metabolic effects of KD. We have found that choline was more effective than methionine in decreasing the liver steatosis of KD-fed mice. On the other hand, methionine supplementation was more effective than choline in restoring weight gain and normalizing the expression of several fatty acid and inflammatory genes in the liver of KD-fed mice. Our results indicate that choline and methionine restriction rather than carbohydrate restriction underlies many of the metabolic effects of KD.08/2013; 2(3):306-13. DOI:10.1016/j.molmet.2013.07.003
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- "Numerous discussions and investigations have focused on whether sedentary lifestyles, contemporary changes in diet, or both are responsible for the rise in obesity found throughout Westernized cultures. Proponents of the diet change argument point to the fact that our current diet is comprised of unbalanced nutrients, mainly too many carbohydrates, and has a total caloric intake that is well above our daily needs  . Some anthropologists who subscribe to this view believe that early humans (hominids) consumed a significant amount of meat and possibly obtained most of their food from hunting . "
ABSTRACT: Metabolic syndrome, as manifested by visceral obesity, hypertension, insulin resistance, and dyslipidemia, is reaching epidemic proportions in the Western World, specifically the United States. Epidemiologic studies suggest that the increased prevalence of metabolic syndrome directly correlates with an increase in the consumption of fructose, mainly in the form of high-fructose corn syrup. This inexpensive alternative to traditional sugar has been increasingly utilized by the food industry as a sweetener since the 1960s. While augmented caloric intake and sedentary lifestyles play important roles in the increasing prevalence of obesity, the pathogenesis of hypertension in metabolic syndrome remains controversial. One intriguing observation points to the role of salt in fructose-induced hypertension. Recent studies in rodents demonstrate that increased dietary fructose intake stimulates salt absorption in the small intestine and kidney tubules, resulting in a state of salt overload, thus setting in motion a cascade of events that will lead to hypertension. These studies point to a novel interaction between the fructose-absorbing transporter, Glut5, and the salt transporters, NHE3 and PAT1, in the intestine and kidney proximal tubule. This paper will focus on synergistic roles of fructose and salt in the pathogenesis of hypertension resulting from salt overload.07/2011; 2011:392708. DOI:10.4061/2011/392708
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ABSTRACT: A quasi-zero reactive power demand which is mandatory in single-phase AC (25 kV/50 Hz) traction systems is considered. Multilevel converter structures and high-performance control techniques have been developed to fulfil this goal in AC heavy traction drives. The tasks of the three level rectifier are described in detail. The current control logic is particularly suitable for applications to multilevel bridges. Advantages deriving from the use of a medium-voltage converter with three different DC potentials are discussed. Digital simulation performed using the general-purpose electromagnetic transients program made it possible to verify the effectiveness of the regulating techniques on the whole system. By controlling converters suitably, the reactive power flowing was reduced to quasi-zero values having a constant voltage on the DC-link and minimizing the harmonic content of the line current in every load condition. Another regulation technique was studied to balance the voltage on condensers which, acting exclusively on the rectifier and not using dissipating techniques or raising the device switching frequency, manage to keep the unbalance DV within a prefixed bandApplied Power Electronics Conference and Exposition, 1990. APEC '90, Conference Proceedings 1990., Fifth Annual; 04/1990