Why low carb diets “work”- yes.. using the word (work) extremely loosely..
Weight loss or gain is primarily related to total caloric intake, not the macronutrient profile of the diet. The weight lost on a low carbohydrate diet can be attributed to two factors: low caloric intake and loss of fat-free mass. If an individual begins dropping carbohydrate rich foods from his or her diet, it is inevitable that caloric intake will drop as a result. Added to the caloric reduction, are dwindling glycogen stores. For every gram of glucose taken out of glycogen, it brings with it 2.7g of water. This loss of muscle glycogen (including water) can be quite significant in the first week of a low carb diet, and adds to the pounds lost on the scale. This is how low carbohydrate fad diets can promise dramatic weight loss in such a short period. Long term success in weight loss is associated with realistic eating style, not one that severely limits or omits one of the macronutrients.