High-Protein Diets
Hidden Dangers

Ross Hume Hall, Ph.D.
biochemistry, nutrition,  food technology.

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Supplement or Not




A high-protein diet is a starvation diet. Those steak, fried chicken, and cream diets cause weight loss at a price. The human brain runs on carbohydrate not protein or fat. When carbs are absent the body flips into starvation mode. O.K. for emergencies but not for long- term health or your brain.

We have two new kittens in the house and I was looking at the nutrition label of the kitten food I bought in a pet store. Thirty-six percent of calories derived from protein. I guess our kittens are right in stride with those high-protein, low-carbohydrate diets that are all the rage.

But unlike folks who follow these diets to lose weight, our kittens gained weight, doubling in size faster than you can say steak and whip cream. The kitty diet got me to thinking. Catsĺ all carnivores for that matterĺ thrive on high-protein food. Can human beings thrive on such a high proportion of protein calories?

Well human beings are not cats, which should be obvious. High-protein food flows smoothly through the catís system, converted into kitty energy and more cat. Not so in the human. The human digestive system is designed to accommodate a mixture of foods, both plant and animal, definitely lower protein and much more carbohydrate.

A high-protein diet knocks the human metabolic system off kilter, The body thinks it's staving.

A high-protein diet based on steak and fried chicken knocks the human digestive system off kilter. The diet sends the wrong signal to the body. Although the individual may be eating a fair amount of food, the body is fooled into thinking itís starving. Alarm bells start ringing and the bodyís metabolism flips into emergency mode, a condition known as ketosis.

Itís unlikely people following a high-protein, low carbohydrate diet think they are living the life of a starving person. Yet thatís exactly what happens when their bodies switch into ketosis.

Why does the body need an emergency mode in case of starvation. Why doesnít the body just consume those fat stores wrapped around midriff or thigh. Itís not that simple. Itís all to do with the brain. The brain in one a sense is like a computer. Unlike the heart, which can operate at variable speeds from high to low, the brain is either turned on or turned off. In the off state, youíre dead. Thus, during starvation the body has a single priority: keep the brain turned on, keep the brain running at all costs.

The brain is normally fueled by blood sugar and the source of blood sugar is the carbohydrate you eat. Now what, if your carbohydrate intake for the day is the equivalent of two pieces of dry toast. This is about the amount of carbohydrate allowed, for example, in the popular Dr. Atkinís diet.

That much carbohydrate is less than a tenth of the brainís daily needs. In absence of dietary carbohydrate, the body starts manufacturing substances called ketone bodies, hence the name ketosis. The ketone bodies prevent the brain from shutting down, because this vital organ starts burning the ketone bodies in place of sugar.

It is not a very efficient condition. But that is exactly what proponents of high-protein, low-carbohydrate diet want. Fat instead of being completely burned for energy is partially converted into things, called ketone bodies.

The brain takes up some of these substances, while the rest exit via the urine. It means for a given amount of walking or running or just plain sitting around, the body consumes more fat than it normally would. Sounds good, but hold on. Thereís a downside.

In my nutrition classes for nurses and medical students Iíd take up the subject of ketosis as an unnatural, an unwanted event, a body out of tune. There are disease conditions as well as starvation that force the body into ketosis. Iíd point out that when you spot this problem in a patient, time to take corrective action.

But now weíve got-- goodness knows how many-- folks embracing ketosis as if it were as natural and wonderful as falling in love. No question the high-protein, low-carbohydrate diet cause people to lose weight. What else do they lose? Erosion of general health? Medical and nutrition authorities have a low opinion of this skewed diet.

The United States Department of Agriculture (USDA) in a 2001 report advises: stick with the kind of balance nature intended for humans, no more than 20 percent of calories as protein. Eat plenty of fruits and vegetables. Half your calories at least from carbohydrate foods.

High-protein gurus cite carbohydrate as an  enemy.

That much carbohydrate? If you read the many diet books touting a high-protein, low-carbohydrate diet, you see carbohydrate cited as the enemy. Why? It has to do with the hormone, insulin. These books say carbohydrate provokes release of the hormone, insulin, shocking the body--not good.

Insulin shocks over the years indeed can contribute to diabetes and heart disease. But why lump all carbohydrates together? The class includes sugars, white flour, whole grains and vegetables. How you consume the carbohydrate matters. Drink a soft drink or eat a candy bar on a empty stomach and youíll provoke plenty of insulin. Because the sugars in these foods race into the blood.

But carbohydrate taken in a mixed meal or as whole grains or whole fruit does not overwork oneís insulin USDA makes this point in saying: get your carbohydrates from whole grain breads and pastas, brown rice, and vegetables.

If nature had intended humans to eat like a cat she would have given us claws and a relatively small brain ( no offense to cats) The big human brain is a voracious consumer of carbohydrates,. up to a fifth of daily calories. This fact of life seems to have escaped promoters of high-protein dieters.


© Ross Hume Hall 2002, All rights Reserved

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