Blow to High-Protein Diets
Health Scout News Reporter
choice is yours: If you follow a high-protein, low-carbohydrate
such as the Atkins Diet, you'll probably shed pounds.
However, you're also putting yourself at risk for excruciating
stones and possibly bone loss, new research has found.
"This is not a healthy way to lose weight," says Dr. Chia-Ying
co-author of the study and an assistant professor of internal
University of Texas Southwestern Medical Center in Dallas.
The study appears in the August issue of The American Journal of
Wang and her colleagues put 10 healthy, not overweight, adults on
Atkins Diet, one of several popular weight-loss plans that
diet mainly of meats, dairy products and some vegetables but very
fruit, bread or other grains.
During the first two weeks of the study, the subjects ate their
diet. During the second two weeks, they ate a highly restricted
"induction" diet that followed the Atkins plan and included less
grams of carbohydrates daily. That's about what you'd find in one
During the next four weeks, participants were allowed to eat
more carbohydrates (40 grams a day), the same amount called for in
Atkins Diet. Each person also took a multivitamin tablet daily.
The researchers measured the level of citrate in the urine.
citrate inhibits kidney stones, rock-like accumulations of calcium
other minerals in the kidneys that can cause extreme pain and, in
cases, severe illness, Wang says.
They found levels of urinary citrate dropped by 25 percent during
first phase of the diet. The level of urinary citrate increased
when the carbohydrates were increased during the next four weeks.
At the same time, researchers found acid excretion in the blood
as much as 90 percent during the phase of the diet in which
were most restricted. Acid load fell only slightly during the next
of the diet, when slightly more carbohydrates were permitted.
The acid level rose for two reasons, Wang says. The first is that
proteins have a high acidic content. The second has to do with the
metabolism of fats.
Carbohydrates are a ready source of energy for the body. When you
restrict those, the body turns to other sources of energy,
When the body burns fat, ketone bodies are formed. An overload of
bodies can lead to a condition called ketoacidosis, when the blood
Chronic acid load in the blood suppresses osteoblasts, cells that
build bone, and stimulates osteoclasts, cells that break down
bone is broken down faster than it's built up, bone strength
To maintain bone strength, these processes have to be in balance.
And yet, the subjects did lose weight on the diet.
The average weight loss during the first two weeks of the diet was
6 to 7
pounds. After two weeks, they lost, on average, an additional 1 to
pounds a week.
"We are not questioning the value of the diet in producing weight
says Dr. Kashayer Sakhaee, co-author of the study and a professor
internal medicine at the medical center. "We are investigating a
countermeasure so that subjects can benefit from weight loss
experiencing the side effects of increased risk of stones and bone
The researchers did not measure the actual number of cases of
stones or the change in bone density.
Dawn Jackson, a spokeswoman for the American Dietetic Association,
plenty of previous research has linked diets high in animal
sodium to kidney stones.
"Everybody is trying all sorts of fad diets," Jackson says. "At
you've got 45 percent of women and 25 percent of men trying to
weight. This is a very vulnerable time for people. They are
Jackson recommends a diet of moderation. If you're trying to lose
cut back a little on what you're eating and give it a little time
"The bottom line is small changes you can make to the diet you're
currently eating are best, and so is a diet that has a lot of
lot of balance and moderation," she says.