The Benefits of Protein
Beef up your knowledge of protein and good dietary sources.
The Drawbacks of High-Protein Diets continued...
Christopher D. Gardner, PhD, assistant professor of medicine at Stanford
University in Palo Alto, Calif., tells WebMD that high-protein diets like the
Atkins regimen may trade short-term benefits for long-term health consequences.
Among the risks: The body produces ammonia when it breaks down protein. No one
knows the long-term risks of higher levels of ammonia in the body.
Also, there is evidence to suggest that people who eat high-protein diets
typically excrete excess calcium in their urine, says Deborah Sellmeyer, MD,
assistant professor of medicine and director of the Center for Osteoporosis
at the University of California at San Francisco. This suggests that the body
is releasing stores of calcium into the bloodstream to counteract an increase
in acids caused by protein consumption (calcium buffers, or neutralizes,
acids). Too much calcium loss could lead to osteoporosis down the road,
Lastly, there are the obvious concerns. Carbohydrate foods shunned by some
people on low-carb diets include fruits and vegetables, which are the best
sources for vitamins, fiber, and antioxidants -- nutrients that help prevent
disease. By contrast, animal foods that are high in protein are usually also
high in saturated fats, which increase the risk for heart
disease, stroke, diabetes, and
several types of cancer.
The American Heart Association warns: "Reducing consumption of [carbs]
usually means other, higher-fat foods are eaten instead. This raises
cholesterol levels even more and increases cardiovascular risk." The AHA also
notes that by concentrating on protein sources and skipping carbs, dieters may
be getting too much salt, and not enough calcium, potassium, or magnesium,
which are typically found in fruits, vegetables, and whole grains.
The (Short-Term) Case for High Protein Diets
While no one knows the effect of eating a high-protein diet over the long
term, the diet appears to be safe and effective for up to six months.
Frank Hu, MD, PhD, assistant professor in the Department of Nutrition at
Harvard University School of Public Health in Boston, asked a student to review
published studies on high-protein diets and try to answer these four important
Do high protein diets increase fat burning in the body?
Do they increase satiety (the sense of being "full" or "satisfied" after a
Do they decrease subsequent energy (calorie) intake by the body?
Do they lead to weight loss?
For the most part, says Hu, the answers are "yes." Protein can be converted
by the body into glucose for energy, but it takes twice as much effort as
converting carbohydrates or fats into glucose. The extra effort translates into
fewer calories available, Hu said at a recent symposium on the science of obesityobesity.
When it comes to feeling full, the clinical studies consistently showed that
high-protein diets increase satiety and decrease hunger compared with high-fat
or high-carbohydrate diets. In addition, most, but not all of the studies
reviewed showed that most people on high-protein diets took in about 10% less
energy (roughly 200 calories) per day, which could account for at least some of
the weight loss seen with this type of diet.