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Low-Carbohydrate Diets, Weight Loss and CaloriesLow Carb Weight Loss Theory on CaloriesProponents of high-fat, low-carb diets dismiss the notion that caloric intake is important to either weight gain or weight loss. They claim that "most overweight individuals do not overeat" , even as they suggest that high-carb meals leave individuals less satisfied than meals that contain adequate fat, resulting in increased hunger and increased food intake. They suggest that those who do overeat do so "because of a metabolic component driving them on, most often a truly addictive craving for carbohydrates". Because "carbohydrates are addictive," the carbohydrate "addict" continues to eat carbohydrates, producing more and more insulin, which inhibits brain serotonin release. Reductions in this "satiety" neurotransmitter result in a decreased sense of satisfaction. With respect to weight loss, Atkins claims that on a low-carb diet there are "metabolic advantages that will allow overweight individuals to eat as many or more calories as they were eating before starting the diet yet still lose pounds and inches". Carbs and InsulinFurthermore, proponents contend overproduction of insulin, driven by high carb intake, is the cause of the metabolic imbalance that underlies obesity. Eating too much carbohydrate results in increased blood glucose, increased blood insulin, and increased TGs. An already overweight person who continues to overeat carbohydrates develops hyperinsulinemia and insulin resistance, "resulting in insulin’s lack of effectiveness in converting glucose into energy, but enabling glucose (e.g. dietary carbohydrate) to be stored as fat". Carb-Restriction in Daily DietAdvocates of low-carb diets propose a simple solution to this "vicious cycle" of carb addiction, carb-overeating, hyperinsulinemia, decreased glucose use and increased fat storage. It involves restricting carbs severely enough to produce ketosis. The ketosis is a reliable indicator of fat mobilization. In this condition, the key benefit is that blood glucose and blood insulin levels are reduced, and appetite is suppressed. In short, authors contend that a high-fat, low-carb, high-protein, ketogenic diet results in weight loss, body fat loss, preservation of lean body mass, and correction of serious medical complications of diabetes, heart disease, and high blood pressure. The contention is that the high-fat, low-CHO diet supports long-term health, controls weight without hunger, and should be followed for the rest of one’s life. --------------- Scientific Assessment of Low Carb Diet TheoriesWhat is the effect of diet composition on weight loss, e.g., will consuming a high-fat, low-carb diet result in weight loss regardless of caloric intake?Answer: Energy intake and energy expenditure are highly relevant when looking at weight gain and weight loss. Overweight and obesity results from an energy imbalance (e.g., excess caloric intake, decreased energy expenditure, or both). Reduction of body weight and body fat can be achieved by creating an energy deficit (e.g., restricting energy intake, increasing energy expenditure, or a combination of the two). Atkins calls these basic thermodynamic principles "a millstone around the neck of dieters and a miserable and malign influence on their efforts to lose". But do followers of high-fat, low-carb diets have a metabolic advantage that enables them to eat a greater number of calories, and still lose body weight and body fat?It seems not. No scientific evidence exists to suggest that low-carb ketogenic diets have a metabolic advantage over more conventional diets for weight reduction. Studies consistently show that under conditions of negative energy balance, weight loss is a function of caloric intake, not diet composition. In all cases, individuals on high-fat, low-CHO diets lose weight because they consume fewer calories. --------------- How are low carb diets performing in clinical weight loss trials?In several small weight loss trials, low carb programs have performed well (compared to more orthodox lower-fat diets), with better blood-glucose control and slightly faster weight loss. Evidence from larger and longer-term studies is now awaited to see if there are any long-term health effects of low carb diets, as at least one clinical weight loss trial showed that a high-fat low-carb diet had negative effects on several indicators for increased heart risk. Sources include: NIDDK and Carbohydrates InformationRelated Low Carb Diet Links Information
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