Many studies have shown that Low Carb Diets do result in weight loss, and in most cases provide better results than Low Fat Diets. While very effective, the Negative Health Effects of Low Carb Diets can not be ignored.
When you go on a strict Low Carb Diet your body becomes starved of carbohydrates. In the long term this can result in a Metabolic Disorder known as 'Ketosis'. If you develop Ketosis, it will leave you with no energy, sluggish, tired and lethargic. The Negative Health Effects of Ketosis seem to be reversed by just eating high carb foods once again. While this reverses the negative effects, all the weight that was lost will most likely return once you start eating high carb foods again.
While the full extent of the Negative Effects of Ketosis are still being researched, some studies have shown that apart from low energy levels, people on low carb diets did not perform as well doing higher order mental tasks.
To reduce or negate any of the Negative Health Effects of Low Carb Diets, moderation and regular exercise should be considered. An alternative to a strict low carb or low calorie diet would be something like a Calorie Shifting Diet.
While a Low Carb Diet has been proven to work, the long term Negative Health Effects should be taken into consideration. If you do decide on a diet like this it would be a good idea to consult a medical professional before doing so.