U.S. Environmental Protection Agency. 1200 Pennsylvania
Avenue, NW, Washington, DC 20460. 202-272-0167.
<www.epa.gov>.
Centers for Disease Control and Prevention. 1600 Clifton
Road, NE, Atlanta, GA 30333. 1-800-CDC-INFO
(1-800-232-4636) or 404-639-3534.<www.cdc.gov>.
Crohn’s and Colitis Foundation of America. 386 Park Ave-
nue South, 17th Floor, New York, NY 10016. 1-800-
932-2423.<www.ccfa.org>.
American Gastroenterological Association. 930 Del Ray
Avenue, Bethesda, MD 20814. (301)654-2055.
<www.gastro.org>.
International Foundation for Functional Gastrointestinal
Disorders Inc. P.O. Box 170864, Milwaukee, WI- 11.<www.iffgd.org>.
Monique Laberge, Ph.D.Diet drugs
Definition
Diet drugs are medications that may help obese
people lose weight when the drugs are used together
with a program of diet and exercise. Historically,
many drugs have been used as weight loss aids, and
some ineffective products have been marketed with
claims of helping in a program of weight loss.Purpose
All diet drugs are intended to reduce caloric intake
or increase calorie usage, however the methods vary.Description
Appetite suppressants (anorexiants)
Most FDA-approved weight loss drugs suppress
appetite by affecting one or more neurotransmitters in
the brain. These are hormones control appetite and
mood. The model for these drugs is amphetamine,
although there are many closely related drugs includ-
ing the botanical product epehdrine. The mechanism
of action of amphetamines on appetite suppression is
not fully understood. It is known that amphetamines
and amphetiamine-like drugs cause the release of nor-
epinephrine and dopamine. Although they are stimu-
lants, amphetamines do not increase the basal
metabolic rate, the rate at which the body uses energy
while in a resting state. Phenylpropanolamine had
been approvel by the United States Food & Drug
Administration as an over-the-counter aid to diet in1983, but this approval was withdrawn after several
reports of hemorrhagic stroke associated with use of
the drug.
Most weight loss drugs are approved for only a
few weeks, and weight rapidly returns once the drug is
discontinued. Long-term studies do indicate that con-
tinued use of weight loss drugs may be effective in
maintaining weight loss, but in most cases long-term
studies have not been conducted to adequately dem-
onstrate safety. This was a particular problem with
amphetamine and its derivatives, which are classified
as controlled substances. Sibutramine, sold under the
brand name Meridia, was approved by the FDA in
1997 for use up to two years. Safety and efficacy
beyond two years has not been established. Sibutr-
amine reduces appetite by inhibiting the reuptake of
norepinephrine, dopamine, and serotonin. One study
found that patients taking sibutramine lost an average
of 7–10 lb (3–5 kg) more over one year than those on a
low-calorie diet alone.
High fiberfoods have also been advocated as
appetite syppressants. A typical example is gluco-
mannan, a dietary fiber derived from the root of the
elephant yam or konjac plant, which is native to Asia.
The theory behind use of foods that contain non-
digestable fiber had been that these foods caused
abdominal distention, swelling of the stomach, which
was believed to cause a feeling of fullness, without
increasing calorie intake. Studies and reviews of the
effects of glucomannan and other non-nutritive fiber
products such as bran have had varying results, but
several of these studies have been encouraging. One
Norwegian study compared three different kinds of
fiber along with a highly calorie restricted diet and
reported ‘‘Glucomannan induced body weight reduc-
tion in healthy overweight subjects, whereas the addi-
tion of guar gum and alginate did not seem to cause
additional loss of weight.’’ A British study reviewed
the effects of guar gum, a fiber which is often used as a
thickening agent in food products, for its value in
weight reduction. The researchers concluded that
guar gum was not effective in aiding weight loss and
the risks associated with taking guar gum outweight its
benefits. It appears that fiber, or the stomach expan-
sion which fiber causes, is not adequate to reduce
calorie intake. If there is a special benefit to gluco-
mannan as indicated by the positive studies, its mech-
anism of action has not been explained.
Past evidence indicated that elevated blood glu-
cose reduced appetite. This belief was the basis for the
claim that sweets before meals would ruin an appetite.Diet drugs