"DRS" <
[email protected]> wrote in message news:<
[email protected]>...
> "andres muro" <[email protected]> wrote in message
> news:[email protected]
> > "DRS" <[email protected]> wrote in message
>
> [...]
>
> >> The question is, since you made the original claim, can you back it
> >> up?
Let me try:
The Protein Myth
The Building Blocks of Life
Protein is an important nutrient required for the building,
maintenance, and repair of tissues in the body. Amino acids, the
building blocks of protein, can be synthesized by the body or ingested
from food. There are 20 different amino acids in the food we eat, but
our body can only make 11 of them. The 9 essential amino acids which
cannot be produced by the body must be obtained from the diet. A
variety of grains, legumes, and vegetables can also provide all of the
essential amino acids our bodies require. It was once thought that
various plant foods had to be eaten together to get their full protein
value, otherwise known as protein combining or protein complementing.
Intentional combining is not necessary to obtain all of the essential
amino acids.1 As long as the diet contains a variety of grains,
legumes, and vegetables, protein needs are easily met.
Protein Requirements
With the traditional Western diet, the average American consumes about
double the protein her or his body needs. Additionally, the main
sources of protein consumed tend to be animal products which are also
high in fat and saturated fat. Most individuals are surprised to learn
that protein needs are actually much less than what they have been
consuming. The Recommended Dietary Allowance (RDA) for protein for the
average, sedentary adult is only 0.8 grams per kilogram of body
weight.2 To find out your average individual need, simply perform the
following calculation:
* Body weight (in pounds) X 0.36 = recommended protein intake
However, even this value has a large margin of safety, and the body's
true need is even lower. Protein needs are increased for women who are
pregnant or breastfeeding. In addition, needs are also higher for
active persons. As these groups require additional calories, increased
protein needs can easily be met through larger intake of food consumed
daily. Extra serving of legumes, tofu, meat substitutes, or other high
protein sources can help meet needs that go beyond the current RDA.
The Problems with High-Protein Diets
High protein diets for weight loss, disease prevention, and enhanced
athletic performance have been greatly publicized over recent years.
However, these diets are supported by little scientific research.
Studies show that the healthiest diet is one that is
high-carbohydrate, low-fat, and moderate in protein. Increased intake
of whole grains, fruits, and vegetables are recommended for weight
control3 and preventing diseases such as cancer4 and heart disease.5
High-carbohydrate, low-fat, moderate-protein diets are also
recommended for optimal athletic performance.6 Contrary to the fad
diets currently promoted by some popular books, a diet that is high in
protein can actually contribute to disease and other health problems.
Osteoporosis. Diets that are rich in protein, especially animal
protein,7 are known to cause people to excrete more calcium than
normal through their urine and increase the risk of osteoporosis.
Plant-based diets, which provide adequate protein in addition to
calcium through the consumption of leafy green vegetables, beans, and
fortified fruit juices, can help protect against osteoporosis.
Cancer. Although fat is the dietary substance most often singled out
for increasing one's risk for cancer, animal protein also plays a
role. Specifically, certain proteins present in meat, fish, and
poultry, cooked at high temperatures, especially grilling and frying,
have been found to produce compounds called heterocyclic amines. These
substances have been linked to various cancers including those of the
colon and breast.8-10 A diet rich in whole grains, fruits, and
vegetables is important in decreasing cancer risk,4 not to mention
adding more healthful sources of protein in the diet.
Kidney Disease. When people eat too much protein, it releases nitrogen
into the blood or is digested and metabolized. This places a strain on
the kidneys which must expel the waste through the urine. Kidney
problems may result in individuals who are susceptible to disease.
Cardiovascular Disease. Diets high in fat and saturated fat can
increase one's risk of heart disease. High-protein diets often
encourage consumption of meat, eggs, and dairy products, which are all
high in cholesterol, fat, and saturated fat. The most popular of the
high-protein diets have been described as containing excessive amounts
of these artery-clogging products.11 Adequate protein can be consumed
through a variety of plant products which are cholesterol-free and
contain only small amounts of fat.
Weight Loss Sabotage. Many individuals see almost immediate weight
loss as a result of following a high-protein diet. In fact, the weight
loss is not a result of consuming more protein, but by simply
consuming less calories. Over the long run, consumption of this type
of diet is not practical as it can result in the aforementioned health
problems. As with any temporary diet, weight gain is often seen when
previous eating habits are resumed. To achieve permanent weight loss
while promoting optimal health, the best strategy involves lifestyle
changes including a low-fat diet of grains, legumes, fruits, and
vegetables combined with regular physical activity.
Protein Checklist
High protein diets are unhealthy. However, adequate but not excess
amounts of protein to maintain body tissues, including muscle, are
still important and can be easily achieved on a vegetarian diet. If
you are uncertain about the adequacy of protein in your diet, take
inventory. Although all protein needs are individual, the following
guidelines can help you to meet, but not exceed, your needs.
* Aim for 5 or more servings of grains each day. This may include
1/2 cup of hot cereal, 1 oz. of dry cereal, or 1 slice of bread. Each
serving contains roughly 3 grams of protein.
* Aim for 3 or more servings of vegetables each day. This may
include 1 cup of raw vegetables, 1/2 cup of cooked vegetables, or 1/2
cup of vegetable juice. Each serving contains about 2 grams of
protein.
* Aim for 2 to 3 servings of legumes each day. This may include
1/2 cup of cooked beans, 4 oz. of tofu or tempeh, 8 oz. of soymilk,
and 1 oz. of nuts. Protein content can vary significantly,
particularly with soy and rice milks, so be sure to check labels. Each
serving may contain about 4 grams to 10 grams of protein. Meat
analogues and substitutes are also great sources of protein that can
be added to your daily diet.
References
1. Position of the American Dietetic Association: vegetarian diets. J
Amer Diet Assoc 1997;97(11):1317-21.
2. Munoz de Chavez M, Chavez A. Diet that prevents cancer:
recommendations from the American Institute for Cancer Research. Int J
Cancer Suppl 1998;11:85-9.
3. Position of the American Dietetic Association: weight management. J
Amer Diet Assoc 1995;95:809.
4. World Cancer Research Fund. Food, Nutrition and the Prevention of
Cancer: A Global Perspective. American Institute for Cancer Research.
Washington, D.C.: 1997.
5. Ornish D, Brown SE, Scherwitz LW. Can lifestyle changes reverse
coronary heart disease? Lancet 1990;336:129-33.
6. Position of the American Dietetic Association: nutrition for
physical fitness and athletic performance for adults. J Amer Diet
Assoc 1993;93:691.
7. Zemel MB. Calcium utilization: effect of varying level and source
of dietary protein. Am J Clin Nutr 1988;48:880-3.
8. Potter JD. Nutrition and colorectal cancer. Cancer Causes Control
1996;7(1):127-46.
9. Giovannucci E, Goldin B. The role of fat, fatty acids, and total
energy intake in the etiology of human colon cancer. Am J Clin Nutr
1997;66(6suppl):1564S-71S.
10. De Stefami E, Ronco A, Mendilaharsu M, et al. Meat intake,
heterocyclic amines, and risk of breast cancer: a case-control study
in Uruguay. Cancer Epidem Biomark Prev 1997;6:573-81.
11. Titchenal CA, Dobbs JC, Hetzler RK. Macronutrient composition of
The Zone diet based on computer analysis. Med Sci Sport Exer
1997;29(5):S126.
07/12/99
