Once again the terms high and low in a diet plan say very little about anything.  What is a high carbohydrate diet?  Pizza I suppose.  What is a low carbohydrate diet?  Celery?  For our purposes here lets say that low carbohydrate diets are below 30 percent carbohydrate consumption on an otherwise appropriate caloric intake.  I have tried numerous Low or No carbohydrate diets. They do work fairly well if the calorie intake of protein and fat is high enough to minimize the catabolism of muscle and protein. The concept of Low carbohydrate dieting is that you will not convert excess carbohydrate into fat and on many of the very low carbohydrate diets, you will also begin to burn fat instead of carbohydrate. This is called Ketosis. Ketosis is not going to happen if the carbohydrate intake level is still too high for that particular individual so the reason most low carbohydrate diets work is simply that the dieter is watching intake of carbohydrate and other fuel sources, very possibly for the first time in a long while.  You might feel irritable and foggy on a low carbohydrate diet since the brain is being deprived of its first choice of fuels, but this will usually go away and leave you feeling  calm and level.  I suggest the Body Opus diet if you wish to really go after that stubborn fat and still feel like you can participate in normal life while you are dieting.  DO NOT stay on a low or no carbohydrate diet longer than two weeks without taking a break and returning to normal ratios of carbohydrate, protein, and fat such as 40-30-30 or 50/30/20.  Your body needs the vegetables, fruits, and macro-nutrients that these foods provide.  Ketogenic diets seem to have a strong association with stroke and heart failure so please be careful on these diets.  There are certainly better and more healthy ways of losing fat than going on a low or zero carbohydrate diet.  All in all, if it does not have real terms or percentages and real numbers then stay away from it.  How on Earth can you know if your eating program is healthy and successful if it has no way to measure it.  Words like high and low just lead to frustration and confusion.