Some of the more popular diets out there today come in the form of low-carb. There are multiple approaches to why they say this works, from the idea that it's easier to gain weight from carbohydrate calories than from protein and fat calories to the idea that eating fewer carbs will promote weight loss due to the fact that unbalancing your diet will cause an increase in your metabolism.
Your body does need carbohydrates for fuel, it can survive solely on protein and fat if necessary, but your brain can't, the brain requires carbohydrates, it has no way of using protein or fat energy, which is enough reason for many people to avoid low-carb diets.
Low-carbohydrate diets also promote ketosis, when weight loss occurs, fats and proteins are used by your body to create energy, when the body has a lack of carbohydrates it can't properly break down the fats into fatty acids for fuel which produces ketone bodies, causing ketosis. Ketosis sounds bad but it really isn't, however one of the side effects of ketosis can be bad breath, caused by acetones (one of the bodies from ketosis) being expunged through your breath.
As I mentioned earlier one of the benefits claimed by the promoters of low-carb diets is that unbalancing your diet will increase your metabolism, this simply is not true. Other than short term bursts from drugs, the only way to raise your metabolism is through exercise.
The American Heart Association has plenty to say on low-carb diets, including the Atkins, the Zone, Sugar Buster, and the Stillman diet. Robert H. Eckel, MD, chairman of the American Heart Association's Nutrition Committee had this to say, "They put people at risk for heart disease and we're really concerned about this". "These diets will raise the … bad cholesterol and increase the risk for cardiovascular disease, particularly heart attacks."
Judith Stern, professor of nutrition and internal medicine at the University of California, Davis said this on the subject, "You want my response to Atkins saying that his diet can lower your cholesterol and do all sorts of good things for your heart, you know what my response is? Bull! "
Yes, LDL cholesterol (the bad kind) does usually drop as people lose weight from low-carb diets, however, that is due to the weight loss itself, NOT the manner in which it was lost. Plus, it has been shown that if people continue on this diet as a weight sustainer after the weight is lost, "Many people LDL goes up if they remain on the diet …" said Eckel.
Plus, the nutrition committee of the American Heart Association issued a science advisory warning about high-protein diets, they stated:
o Such diets may produce short-term weight loss due to dehydration.
o Weight loss may also occur through caloric restriction resulting from the fact that the diets can be relatively unpalatable.
o These diets often restrict healthful foods that provide essential nutrients.
o Individuals who follow these diets are at potential risk of cardiac, renal, bone and liver abnormalities overall.
o Any improvement in blood cholesterol levels and insulin management would be due to weight loss, not the change in your food.
o A very high protein diet is especially risky for patients with diabetes because it can speed the progression of diabetic kidney disease.