The New York Times
September 10, 2002
High-Fat Diet: Count Calories and Think Twice
By JANE E. BRODY
The debate over high-fat versus low-fat as a means of weight control flared
up again this summer, leaving many weight-conscious Americans thoroughly
confused and most nutrition experts up in arms.
Though billed as a "diet revolution," the high-protein, high-fat, extremely
low carbohydrate diet championed by Dr. Robert C. Atkins is hardly
revolutionary. It was first promoted in the late 1800's by an English
coffin maker and has reappeared periodically in various incarnations, most
successfully since the early 1970's by Dr. Atkins, who promoted it with a
series of books and a clinic that bear his name.
Does it help people lose weight? Of course it does. If you cannot eat
bread, bagels, cake, cookies, ice cream, candy, crackers, muffins, sugary
soft drinks, pasta, rice, most fruits and many vegetables, you will almost
certainly consume fewer calories. Any diet will result in weight loss if it
eliminates calories that previously were overconsumed.
This diet seems easy because it places no limits on the amounts of meats,
fats, eggs, cheese and the like you can eat. These foods digest slowly,
making you feel satisfied longer. Also, a diet without carbohydrates causes
the body to make substances called ketones that may create a mild nausea,
suppressing hunger.
But in a major report last week, the Institute of Medicine of the National
Academies emphasized the importance of balance of nutrients, with
carbohydrates — starches and sugars — making up 45 percent to and 65
percent of daily calories and fats, 20 percent to 35 percent. The panel of
21 scientists also urged Americans to keep as low as possible their
consumption of saturated fats, the foods Dr. Atkins recommends as his
diet's main components.
Testimonials abound from people who have lost scores of pounds —
painlessly, they say — on the Atkins diet. This is not surprising. After
all, how much of a limited category of foods can you eat before you find
yourself eating less and less? With few carbohydrates, the weight initially
comes pouring off — literally — in body water, the first 5 to 10 pounds of
weight loss.
One question I'd like to see answered is how long anyone can stay on such a
scheme and what happens when you start adding back some of the wholesome
foods limited or forbidden on this diet, like sweet corn, grapes,
watermelons, potatoes, carrots, beets or oatmeal.
The Great Unknowns A more important question: For those who stick with the
diet, which allows back very limited amounts of carbohydrate-rich foods,
what happens to their health?
In a study by Dr. Chia-Ying Wang and colleagues at the University of Texas
Southwestern Medical Center in Dallas, reported in August in The American
Journal of Kidney Diseases, just six weeks of a low-carbohydrate,
high-protein diet greatly increased the risk of developing kidney stones.
"This study shows that this is not a healthy way to lose weight," Dr. Wang
said.
What is surprising is that after three decades of simmering and soaring
popularity, the Atkins diet has yet to be tested for long-term safety and
effectiveness.
In an interview, Dr. Atkins said: "A long-term study would cost millions
and millions of dollars. We can afford to do a six-month study." Those
shorter studies, he said, have shown "major improvements in lab tests and
well-being." He said his foundation has contributed to a study under way at
Harvard comparing the short-term effectiveness and health effects of diets
low in carbohydrates versus diets low in fat.
Dr. Abby Block, nutritionist at the foundation, said studies of the Atkins
diet lasting six months to a year and extensive clinical experience, have
shown consistent improvements in blood lipids and glucose levels,
suggesting that the diet can improve health despite its high levels of
saturated fats and cholesterol, long associated with heart disease risks.
Why hasn't the government tested it? One possible reason is that it is
unlikely to be approved by any review committee, given what is known about
the effects of animal fats and cholesterol on the risk of heart disease,
strokes and some cancers, as well as accumulating evidence that diets rich
in fruits and vegetables and moderate in protein and fat can prevent
diseases like high blood pressure, prostate cancer, heart disease and
diabetes.
The Atkins diet is shy on several vital nutrients, including the B vitamins
and vitamins A, C and D, antioxidants that slow the effects of aging, and
calcium. And, a diet rich in animal protein can draw calcium from the
bones, increasing the risk of osteoporosis and hip fractures.
What Are the Facts?
The Atkins diet is attractive to many Americans who have found it hard to
lose weight on a low-fat diet. In recent decades, as Americans have been
admonished to eat less fat, levels of obesity continued to rise, a
situation noted in a recent article in The New York Times Magazine by Gary
Taubes, a science writer, who told me he had lost considerable weight on
the Atkins diet.
But many well-established facts can explain what happened to the American
figure without damning carbohydrates or blaming low-fat diets, per se.
First, Americans are simply eating more — an average of 400 calories a day
more than they did decades ago. Four hundred calories times 365 days
divided by 3,500 (the amount of calories in a pound of fat) equals 41.7
pounds gained in a year, all other things being equal.
Of course, the caloric increase did not happen overnight, but the gradual
increase, with little or no increase in caloric output from physical
activity, can easily explain the creeping obesity that is now approaching a
gallop.
Second, portion sizes have ballooned. A double cheeseburger, jumbo fries
and supersize soda may be a single meal at a restaurant, but they contain
all the calories a person should consume in an entire day. In a recent
survey by the American Institute for Cancer Research, two-thirds of diners
said they ate all they were served — at one sitting — most or all of the
time.
When nutrition experts began urging Americans to cut back on fats, many
filled in by eating more carbohydrates — a lot more than anyone
recommended. Food producers jumped on the bandwagon to produce low-fat
snacks and desserts, and Americans went hog wild, eating as much of them as
they wanted.
Many fat-free foods have as many calories, or nearly as many, as their
original high-fat versions, since sugars and other carbohydrates replace
the fat and reduce the loss of flavor.
Third, Americans are not eating a low-fat diet. Despite a decline in the
percentage of fats in the American diet, most people still eat the same
amount. As caloric intake rose, the percentage of fat calories dropped but
the total amount did not. Americans are eating more of everything,
especially refined carbohydrates, which are made from white flour and
sugars, doing neither their health nor their waistlines any good.
Too many refined carbohydrates can raise blood levels of heart-damaging
triglycerides and may increase the risk of diabetes as well as obesity.
Neither is it wise to cut out all fats. The body needs fat to aid in the
absorption of essential nutrients, fat enhances flavor and satiety, and
some fats actually promote health.
These ideas are not new. Several years ago, I wrote that healthful dietary
fats found in foods like avocados, nuts and fish belong in the diet, both
for disease prevention and weight control. I quoted Dr. Margo Denke of
Southwestern Medical Center: "The swing back to Atkins is a response to the
fact that a low-fat diet hasn't worked for a lot of people because they
stuff in carbohydrates."
To which Dr. Alice H. Lichtenstein, professor of nutrition at Tufts
University in Boston, added: "Reducing fat alone is no guarantee of weight
loss. You must cut calories or increase physical activity."
Dr. Denke concurred: "No matter what anyone tells you, it's calories that
count. Carefully controlled metabolic studies show that it doesn't matter
where extra calories come from. Eat more calories than you expend and
you'll gain weight."
Copyright 2002 The New York Times Company
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