glycemic index. Weight loss in phase 2 is expected to be
1–2 lb (0.6–1 kg) per week. The permitted foods are the
same as in phase one with the addition of whole grain
cereals, oatmeal, whole-grain bread and whole-grain
pasta, barley, low-fat milk, nuts, beans, starchy vegeta-
bles, wine, and most fruits. These items are portion-
controlled. Watermelon, bananas, raisins, white bread,
baked goods, and sugary foods are not allowed. Satu-
ratedfatsandtransfats (animal fats, butter, cream,
fatty meats, some solid-type margarines) are forbidden.
Dieters stay on the phase 2 diet until they have
achieved their desired weight, at which time they move
to phase 3, a maintenance phase. The list of restricted
foods in phase 3 is quite similar to phase 2. Foods
made with white flour and high levels of refined
sugar are sill off limits. Individuals who get off track
and violate the diet in phases 2 or 3 are instructed to go
back to phase 1 and start again.
For a fee, the South Beach diet Website offers tools
to help the dieter stay on track. These include as recipes,
advice from dietitians, food journals, and meal plan-
ners. Daily moderate aerobic exercise and strength
training are recommended for people on this diet.FunctionThe South Beach diet is based on the idea that to
lose weight, the dieter must replace ‘‘bad carbohydrates’’
with ‘‘good carbohydrates’’and ‘‘bad fats‘‘ and ‘‘good
fats’’. Good carbohydrates are defined as those that have
a low glycemic index, while bad carbohydrates have a
high glycemic index in order toreduce insulin resistance.
The glycemic index compares foods on a scale of
1–100 for how much they increase the level of glucose
(sugar) in the blood. When people eat, the level of
glucose in their blood increases. How much it increases
depends on the foods they eat. ‘‘Good’’ foods with a low
glycemic index (below 50) raise blood sugar less than
‘‘bad’’ foods with a high glycemic index (above 50 or
above 65 depending on which authority is consulted).
When blood glucose levels increase, cells in the pan-
creas release the hormone insulin. This signals cells in
the body to convert some of the glucose into a com-
pound called glycogen that is stored in the liver and
muscles and some into fat, stored in fat cells. When
blood glucose levels go down, different cells in the
pancreas release the hormone glucagon. Glucagon sig-
nals cells in the liver and muscle to release glycogen,
which is converted back into glucose and is burned by
the body. If glucose levels continue to be low, fat is also
burned for energy.
When people eat foods that contain a lot of sugar
or carbohydrates that break down rapidly in the body
into glucose (the ‘‘bad’’ carbohydrates of the South
Beach diet) their insulin level spikes. When people eat
carbohydrates that break down more slowly into glu-
cose (the ‘‘good’’ carbohydrates of the South Beach
diet), their insulin level rises more slowly and does not
reach as high a level. When someone eats too many
sugary foods too often, they secrete a lot of insulin,
and eventually cells in the body may become insulin
resistant. Insulin resistance is a factor in type 2 diabe-
tes. By removing all carbohydrates from the diet for
two weeks, the South Beach diet is claims to eliminate
insulin resistance.KEY TERMS
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.
Glucose—A simple sugar that results from the break-
down of carbohydrates. Glucose circulates in the
blood and is the main source of energy for the body.
Glycemic index—A ranking from 1–100 of how
much carbohydrate-containing foods raise blood
sugar levels within two hours after being eaten.
Foods with a glycemic index of 50 or lower are
considered ‘‘good.’’
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.
Hormone—A chemical messenger that is produced
by one type of cell and travels through the blood-
stream to change the metabolism of a different type
of cell.
Insulin—A hormone made by the pancreas that con-
trols blood glucose (sugar) levels by moving excess
glucose into muscle, liver, and other cells for storage.
Insulin resistance—A condition in which the cells
of the body do not respond to insulin to the degree
they normally should. This creates a condition in
which more and more insulin must be used to con-
trol glucose levels in the blood.South Beach diet