Carbohydrate reduction has been a very popular means of weight reduction over
the last 12 years in the US. This popularity largely derives from the now-famous
"Atkins Diet" written by the late Dr. Richard Atkins. While there is little question that
carbohydrate reduction does work to cause weight loss, it generally is difficult for
people to maintain this sort of diet and so far, the long term effects of these diets
on human health remain largely unknown.
1: They are fast. Because most low-carb diets have an "induction phase" during
which people eat extremely low amounts of carbohydrate, they usually cause a
peculiar metabolic condition known as as "ketosis" wherein the body, in order to
feed the brain absent sugar, produces large amounts of "secondary fuel" called
"ketone bodies" that have the effect of reducing hunger and producing diuresis
(water-loss by urination). Because of this water loss, people can lose as much as
ten pounds in their first week on a low-carbohydrate diet. Of course the lost
water is quickly reasimilated when ketosis stops. This accounts for the dramatic
weight fluctuations that accompany low-carb diets.
2: They tend suit the meat-laden American concept of a "meal". Typically,
people on low carbohydrate diets consume a lot of meat. This seems very
appealing to people who may have been long-advised to avoid this kind of food.
3: Dramatic Blood Sugar Control: Often, when a person with type-2 diabetes
starts a low-carbohydrate diet his or her blood sugar levels can literally improve
overnight, sometimes very much. This combined with the improvement in blood
sugar associated with weight loss makes low carbohdrate diets very tempting for
diabetic patients and the physicians who treat them. Nevertheless, few people
can mainain a very low carbohydrate intake for many years so even when it
makes sense for a person to follow such a diet in the short term, a more
macronutrient-balanced approach needs to be considered for the long-haul.
1: No long-term data: So far, we don't have any good research results to help
determine wether low carbohydrate dies are safe and beneficial in the long-term.
2: All-or-Nothing: Because strict low-carbohydrate diets require that people
stay in the fluid-depleting state of ketosis, any "slip-up" or carbohydrate binge
tends to cause rapid fluid regain that, of course, is reflected as a weight
3: Monotony: Meat and cheese for every meal might sound appealing to
someone who has long-refrained from such habits, but within days, many people
find low-carb diets bland, boring and unpleasant.
4: Excessive Protein: Because of the emphasis placed upon meat consumption
within low-carbohydrate diets, many people consume far more protein than they
need. The problem with this is that excess protein cannot be stored by the body
and therefore must be eliminated. This elimination places significant stress on the
kidneys, particularly in the semi-dehydrated state of ketosis. There have been
case-reports of serious kidney damage that appear to be associated with high
protein intake from, among other causes, low-carbohydrate diets.
5:Cultural Evidence is Lacking: One of the most reassuring facts about low-fat
(not low-carbohydrate) is that billions of people around the world consume low
fat diets nearly daily (and have thus consumed for millenia) and live long and
healthy lives. The statistics are far less reassuring as regards low-carbohydrate
Dr. Atkins, in his book, argues that native Americans living in the polar north
("Eskimos") traditionally consumed low-carbohydrate diets (fish, whale meat and
blubber) and remained thin and healthy. While this is true, several practical
problems remain. First, the "Eskimo" diet wasn't merely "low-carbohydrate", it
was practically zero-carb and therefore rather different than the less severe
diets popular today. Second, while the traditional Eskimo lifestyle proves that
people are capable of surviving and even thriving in extremes of diet and climate,
it doesn't argue that given a choice most people would actually choose to live
this way. It still begs the question whether low-carbohydrate diets are liveable.
Low carbohydrate diets and low-fat diets are polar opposites. Low carbohydrate
diets are necessarily high fat diets whereas low fat diets are high in
carbohydrates. This is confusing to many people if they are familiar with one
approach (say low-carb) and then later try the other (low fat). A common
complaint of dieters is the seemingly conflicting advice offered them by
proponents of low carbohydrate and low fat diets.
Low carbohydrate diets are effective and safe for weight control in the short
term. Long term data are lacking.