A Dangerous Obsession

If dieting just wasted your time, it would be bad enough. But dieting is also
very dangerous—not just for anorexics and bulimics but also for average,
everyday dieters. Typical yo-yo dieting (what medical professionals call weight
cycling) doesn’t just damage your self-esteem; it can damage your body as
well. That’s why, unlike most doctors who call dieting a healthy activity, I call
it what it really is: a disease.
How does dieting jeopardize your health? Here’s a short list.

• Dieting hurts your heart and cardiovascular system. Studies of large
groups of people show that yo-yo dieting can increase your risk of death
from cardiovascular disease.6 Why? One recent study found that yo-yo dieting
significantly lowers levels of the “good” cholesterol HDL-C in women,7
and another study of rats showed that weight cycling disrupts levels of serum
cholesterol, triglycerides, glucose, and insulin in ways that could increase
heart disease risk.8 Yo-yo dieting is dangerous for men’s hearts as well as
women’s: one study found that men who experience at least one cycle of major
weight loss and regain are at increased risk of death from cardiovascular disease
compared to men who steadily gain weight or those whose weight
remains stable.9
• Dieting can break your bones. Yo-yo dieting reduces your bone mass
and increases your risk of hip fractures.10 Because we stockpile bone mass
during childhood and early adulthood, it’s particularly dangerous for preteens,
teens, and young adults to diet.
• Dieting can increase your risk of gallstones. Middle-aged women are
especially prone to this painful and sometimes dangerous medical problem,
which often requires major surgery called a cholecystectomy. According to a
recent study, “the risk for cholecystectomy associated with weight cycling [is]
substantial, independent of attained relative body weight.”11 For years, doctors
told patients that the highest-risk group for gallstones is “fat, female, and
forty,” but we’re learning that being overweight may be less risky than weight
cycling.
• Dieting can affect your immune system.When you reduce your calorie
consumption drastically, you also dramatically reduce the numbers of disease-
fighting cells in your body,12 putting you at increased risk for infections
and possibly even cancer.
• Dieting causes changes in the breast. Two recent studies link weight
cycling to DNA damage or abnormal cell changes in breast tissue, meaning
that yo-yo dieting may increase a woman’s risk of breast cancer.13
• Dieting may increase a woman’s risk of having a hysterectomy. It
sounds strange, but research indicates that yo-yo dieting is strongly linked to
menstrual problems serious enough to require removal of the uterus.14
• Dieting can ruin your teeth. Extreme dieting can deprive you of the
calcium you need to have strong, healthy teeth. If you purge after bingeing,
the stomach acids you bring up can cause the enamel on your teeth to erode.
Chronic purging can lead to cavities, tooth staining, and even the necessity
for tooth removal.
• Dieting makes you physically weak. Study after study reports that
physical fatigue is one of the primary side effects of dieting.
• Dieting is bad for your mental health. I’ll talk later about how dieting
can make you feel bad about yourself. But it can also make your brain feel bad.
As I mentioned, women who diet have reduced levels of tryptophan, the building
block of the brain chemical serotonin—and low serotonin levels are linked
to depression, hostility, impulsive behavior, obsessive-compulsive behavior,
and even an increased risk of suicide.
In addition, dieting appears to make you less smart—no kidding. A recent
study found that women had slower reaction times, exhibited poorer immediate
recall of words, and were less vigilant on cognitive tests when they were
dieting than when they weren’t.15
• Dieting can put you at risk for alcohol abuse. Canadian researchers
evaluated the dieting behaviors and alcohol use of nearly two hundred female
university students. They report that levels of food restraint correlated strongly
with how much the women drank and how often they engaged in “binge drinking.”
“Chronic dieting,” the researchers say, “appears to be related to a relatively
heavy drinking pattern that can be characterized as potentially risky.”16