The effect of low carbohydrate on energy metabolism

Abstract

OBJECTIVE: To investigate whether low-carbohydrate diets are efficient for reduction of body weight and through which mechanism. DESIGN: A couple of studies using low-carbohydrate diets in the treatment of obesity are reviewed. Mechanisms for explaining the reduced appetite are described in relation to knowledge on regulation of appetite for fat and carbohydrate. RESULTS: Studies with low-carbohydrate diets demonstrate a rapid weight loss, being more pronounced after 3 and 6 months compared to low-fat diets. After 12 months there is no difference between the low-carbohydrate and the conventional low-fat diet on weight loss. Both diets lead to improvements in risk factors for coronary heart disease, the low-carbohydrate diet leading to a greater decrease in serum triglycerides and increase in HDL cholesterol compared to the low-fat diet. Blood pressure, insulin sensitivity and LDL cholesterol were improved to a similar degree by the two diets. The mechanism for the rapid weight loss with the low-carbohydrate diet is a suppressed appetite, first through the high-protein content of the diet, second through the ketogenic nature of the diet with satiety signals for fat being active and third through the absence of hunger-promoting carbohydrate components like sucrose and/or fructose. CONCLUSION: A rapid initial weight loss occurs with a low-carbohydrate diet due to a suppressed appetite. There is as yet no indication of an increased metabolic rate and an increased thermogenesis by the low-carbohydrate diet. The safety and efficacy of low-carbohydrate diets have to await further studies.

The biochemistry of ketogenesis and its role in weight management, neurological disease and oxidative stress

“…Later, weight loss is more difficult to explain. Some authors have suggested that ketones act on the satiety center of the brain and suppress hunger [13], while others believe that it is simply the physical form of the carbohydrate consumed that affects satiety [33]. Increased lipolysis (due to reduced insulin secretion) does promote weight loss [43], but probably not to a significant extent.…”

Short-Term Carbohydrate-Restricted Diet for Weight Loss in Severely Obese Women

“…There are evidences that the low-carbohydrate diet results in quick weight loss because of enhanced energy expenditure via ketogenesis [29], or simply by appetite suppression due to high protein content [30]. Researchers believe that this weight loss occurs because of the combination of limited food choice with the satiety promoted by the large amount of protein in the diet [14].…”

From birth to adolescence: Vienna 2005 European Childhood Obesity Group International Workshop

“…They concluded that energy metabolism is changed with a low-carbohydrate diet, leading to decreased body weight, mainly because of increased satiety from fat and protein and an increased thermogenesis. 45 Psychology Psychological aspects are important in both the development and the treatment of childhood obesity. We have to use the encounter with the patient as professionally as possible as this is a major tool in treatment.…”