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After hours of sweaty stove-side work, I had created a masterpiece: roasted
red snapper on a bed of linguine draped with mango salsa; sautéed spinach and
potatoes on the side with a bowl of fresh strawberries for dessert. But when
my friend Scott arrived for dinner he wouldn’t eat. He was trying a new
high-protein diet and couldn’t eat carbohydrates. This diet, he hoped, would
help him feel more energetic and improve his athletic performance.
Baffled by news of Scott’s seemingly illogical theory, I set out to learn a
little more about it. What I discovered is one of the greatest current controversies
in nutrition science.
The Pros of High Protein
Since the late sixties, beginning with the work of Dr. Robert Atkins, alternative
doctors have suggested a protein-centric, low-carb diet as a means to lose weight
and feel more energized. This plan has been dismissed repeatedly as an unsubstantiated
fad by most in the medical profession, but continues to find traction among athletes
and dieters alike.
Whether it’s Atkins’ diets, Barry Sears’ popular Zone diet, or Dr. Phil
Maffetone’s 40-30-30 (40% carbs, 30% protein, 30% fat), high protein diets are
based on the premise that carbohydrates induce weight gain through increased
fat storage and perpetually induced hunger. Carbs also lead to peaks and troughs
in energy levels, as well as increased production of insulin. Insulin helps
the blood cells absorb glucose quickly, causing a fast depletion of blood sugar
levels. Insulin has also been associated with increased risk of cancer and
other diseases, protein proponents say.
“Elevated insulin combined with excess carbohydrate calories leads to
increased triglycerides, obesity, and production of pro-inflammatory eicosanoids.
All three are major factors for developing heart disease,” writes Zone advocate
Dr. Paul Kahl.
Without excessive carbohydrates, your body will turn to its fat stores for fuel,
according to this theory. Maffetone also claims a high protein, low carb diet
will ease the mental and physical fatigue commonly experienced after eating, as
well as improve memory, reduce intestinal gas, and alleviate depression. “By
moderating carbohydrate intake to control insulin production, you can increase
your fat burning as an optimal and efficient source of almost unlimited
energy.”
Carbo-Centrists Speak Out
But the research of protein advocates like Atkins or Maffetone isn’t convincing
mainstream nutrition experts, who firmly believe that carbohydrates are the
body’s main source of fuel, especially for active individuals.
“Unfortunately these claims rely on unpublished research or studies that have
not been peer reviewed or controlled, meaning they have little respect in the
scientific community,” wrote Lisa Hark, Ph.D., RD, CDE, in her article “The
Reincarnation of the High Protein Diet.” Hark explains that the high protein
theories are unfounded mainly because your body converts all calories to glucose,
to be stored as fat for energy, regardless of whether those calories come from
carbohydrates or protein. “It’s your overall calorie intake, and not
carbohydrates, that causes fat to be stored. And besides, foods that are high
in protein, such as meats and cheeses, are also high in saturated fat, which we
now know will increase blood cholesterol levels if eaten in excess.”
Most major health organizations, including the American Heart Association,
the National Institute of Health, the American Cancer Society, the Food and
Drug Administration, and the National Cholesterol Education Program endorse
a carbohydrate-centric diet consisting of roughly 30% fat, 10% protein, and
60% carbs.
“I think the 40-30-30 is very unrealistic.” says marathon runner, registered
nutritionist and Rocky Mountain Chapter of the American College of Sports
Medicine board member Cindy Byfield. “I’m a really big believer in a
high-carbohydrate diet for athletic performance. I think athletes are really
hurting themselves by not getting enough carbohydrates.”
You Decide
But when I reported my findings back to my friend Scott, who has played
professional soccer off and on over the past few years and trains regularly,
he felt his experience proved otherwise. Scott followed a modified version
of the Atkins diet, eating heavy amounts of protein but continuing to eat
fruits and vegetables as his only source of carbohydrates—and supplementing
with a multi-vitamin.
“I had a heightened amount of energy. I found that during my day-to-day
routine, I never went through the ups and downs of energy that I used to
have. I used to get tired, need to eat, want to take a nap, then need to
eat again. Without carbs, I was on a more steady, higher plateau throughout
the day,” he said. “With increased energy, I was able to train a little
harder.”
So why did Scott seem to benefit from a diet that flies in the face of all
scientific evidence? I don’t know. Maybe he was really eating more carbs
than he let on (people often underestimate the carbohydrate they take in in
simple sugars, like sugar in their coffee, etc.) or maybe he has an unusual
body chemistry that benefits from a different approach. The fact that
athletes are smashing records right and left, using new training and nutrition
information, such as carbo loading, leaves me thinking that maybe I’ll go
with scientific opinion on this one. On the other hand...
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Can Too Much Protein Hurt?
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We all know that protein is an essential building block in our body’s
growth, but can an overdose of protein be bad?
First, it can lead to kidney problems. Our bodies can’t metabolize
nitrogen, one of the components of protein. Because the body disposes of
nitrogen through the urine, an abundance of protein will not only stress
the kidneys but could cause kidney stones and usually results in dehydration.
In fact, individuals eating a high-protein diet commonly experience a four
to five-times increase in urine volume, Experts say, and this is doubly
harmful when combined with a reduction of carbohydrates in your
diet.
Second, it can lead to dehydration. For every gram of glycogen (from
carbohydrates), your body stores three grams of water. Stop eating
carbohydrates and you not only lose the three grams of water with the
glycogen, but also lose additional fluids from excessive urination. The
more water you lose, the more you’ll need to replace in order to stay
hydrated, according to Experts.
Experts prescribe more protein than the USRDA, but still advocates a
carbo-centric diet. An active individual should have about 1.3 grams of
protein per kilo of body weight each day, she says, and an elite athlete
training hard should increase that amount to about 1.7 g/kg, or roughly
200% USRDA. Research shows that the human body can’t metabolize more
than 1.9 g/kg, and if you’re eating more than that, the
protein will be stored as fat.
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