Protein
Can We Eat Too Much?
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When people concerned about food sustainability consider a vegetarian diet, there is often that knee-jerk reaction, “Really? But where are you going to get your protein from?
In our last column we began to respond to a different question: Can we eat too much protein when following the Standard American Diet? The National Academy of Sciences set the American Recommended Daily Intake for protein at 0.35 grams per pound of ideal body weight. This is more than the 30 grams/day minimum requirement. It works out to 60 grams for a 170-lb man and 45 grams for a 128-lb woman. Even so, most Americans consume between 100 to 130 grams of protein a day. That is almost twice the recommended amount.
Children & Protein
Children do need extra protein, especially during periods of rapid growth. The RDI of 0.35 grams per pound of ideal body weight works out to 17 grams of protein a day for a 50-pound child—a little more than half an ounce. Since children in Western cultures eat the same high-protein diets that adults do, there is very little concern for not getting enough protein!
The problem may well be on the other side of the question. Accumulating evidence suggests that children eating high-fat and -protein diets tend to grow bigger and develop faster. Are they paying the price of a shortened life?
And the amino acid arguments?
Proteins are made of some 20 amino acids. While the body can manufacture 12 of these building blocks, eight amino acids have been proven to be essential for adults. They must be provided by the diet. People used to believe that they had to eat meat and dairy products to supply these “essential” amino acids. The fact that these foods are high in fat and cholesterol, lack fiber, and have detrimental effects on health was, for many years, overlooked or considered irrelevant.
Now we know that these amino acids are easily available from a random selection of plant foods, augmented by the amino acid pool of the body. This is shown in dietary patterns around the world. The staple food in Caribbean countries is black beans and rice. Certain amino acids low in rice are found in the beans, and vice versa. The same is true for the corn tortillas and pinto beans of the Mexicans, and the rice and soybeans relied upon by the Chinese.
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Urea is produced in the processing of protein by the liver. In excess, this urea acts as a diuretic; it pulls water out of the system. A high protein diet therefore may require up to seven times as much water to wash out the waste products from the kidneys. |
The Western world is taking a fresh look at plant foods. They are low in fat, high in fiber, free of cholesterol, full of nutrients, and have plenty of protein. In fact, when enough calories are available from a variety of unrefined plant foods, it’s impossible to create a protein deficiency.
It’s time to bury the myth and catch up with the times. With protein, as with much else in life, too much of a good thing could turn out to be a bad thing.
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