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
Benefits of Low-Carbohydrate Diets:
- 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
"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 assimilated when ketosis stops. This accounts for the dramatic weight
fluctuations that accompany low-carb diets.
- 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.
- 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 carbohydrate
diets very tempting for diabetic patients and the physicians who treat them.
Nevertheless, few people can maintain 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
Problems and Risks of Low-Carbohydrate Diets:
- No long-term data: So far, we don't have any good research
results to help determine whether low carbohydrate dies are safe and beneficial
in the long-term.
- 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 increase.
- 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.
- 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.
- 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 millennia)
and live long and healthy lives. The statistics are far less reassuring as
regards low-carbohydrate diets. 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 livable.
Confusion Caused by Low-Carbohydrate Diets:
- 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. Conclusions: Low carbohydrate diets are effective and safe
for weight control in the short term. Long term data are lacking.