High-protein diet
DefinitionHighproteindiets are diets in which 20% or more
of the total daily calories comes from proteins. A very
high protein diet is one where 30% or more of the total
daily calories comes from protein. By comparison, in
the average American diet about 12–16% of calories
come from protein.OriginsHigh protein diets have been popular off and on
since the 1960s. In the 1960s, Dr. Maxwell Stillman of
the Stillman Diet was one of the first to advocate a
high protein, no carbohydrate,low fat dietfor fast
weight loss. In the 1990s, diet books promoting high
protein diets began to appear on bestseller lists. The
most popular of these ‘‘new’’ high protein diets was the
Atkins Diet. Other high protein diets include theZone
Diet, Protein Power, and Sugar Busters. These diets
are the heirs to the Stillman Diet, slightly modified to
include somecarbohydrates, and repackaged with
some updated terminology and scientific explana-
tions. They encourage high protein diets for weight
loss and/or for bodybuilding.DescriptionAll human protein is made from about 20 differ-
ent small molecules called amino acids. Out of these 20
amino acids, nine are considered essential amino
acids. They are essential because the body cannot
make them from other nutrients and they must be
obtained fully formed from diet.
Both animals and plants are sources of protein.
Animal protein has the higher biological value because
it is a complete protein. Complete proteins contain all
nine essential amino acids. Animal proteins include
meat, poultry, fish, egg whites, and dairy products.
Plant proteins have a lower biological value
because they are incomplete proteins that do not con-
tain all nine essential amino acids. Some plants are
better sources of protein than others because they lack
only one or two essential amino acid. Better plant
proteins include dried beans and bean products such
as tofu (made from soybeans), nuts, and grains such as
corn and quinoa. Many cultures have developed
dishes such as red beans and rice or corn tortillas and
beans that combine these incomplete proteins in the
same meal to provide all the essential amino acids
needed for health.The federal Dietary Guidelines for Americans
2005 recommends that no more than 15% of an indi-
vidual’s daily calories come from protein. The Amer-
ican Heart Association and the National Institutes of
Health state that protein equaling 10-12% of anKEY TERMS
Amino acid—molecules that are the basic building
blocks of proteins
B-complex vitamins—a group of water-soluble
vitamins that often work together in the body.
These include thiamine (B 1 ), riboflavin (B 2 ), niacin
(B 3 ), pantothenic acid (B 5 ), pyridoxine (B 6 ), biotin
(B 7 or vitamin H), folate/folic acid (B 9 ), and coba-
lamin (B 12 ).
Dietary fiber—also known as roughage or bulk.
Insoluble fiber moves through the digestive system
almost undigested and gives bulk to stools. Soluble
fiber dissolves in water and helps keep stools soft.
Enzyme—a protein that change the rate of a chem-
ical reaction within the body without themselves
being used up in the reaction
Essential amino acid—an amino acid that is neces-
sary for health but that cannot be made by the body
and must be acquired through diet.
Glucose—a simple sugar that results from the
breakdown of carbohydrates, and under some con-
ditions proteins and fats. Glucose circulates in the
blood and is the main source of energy for the body.
Glycogen—A compound made when the level of
glucose (sugar) in the blood is too high. Glycogen is
stored in the liver and muscles for release when
blood glucose levels are too low.
Mineral—an inorganic substance found in the
earth that is necessary in small quantities for the
body to maintain a health. Examples: zinc, copper,
iron.
Osteoporosis—a condition found in older individ-
uals in which bones decrease in density and
become fragile and more likely to break. It can be
caused by lack of vitamin D and/or calcium in the
diet.
Quinoa—a high-protein grain native to South
America (pronounced keen-wah)
Vitamin—a nutrient that the body needs in small
amounts to remain healthy but that the body cannot
manufacture for itself and must acquire through
dietHigh-protein diet