|
The Zone
diet is a diet popularized
in books by biochemist Barry
Sears. It advocates balancing protein
and carbohydrate
in 3:4 ratios. It is not primarily a weight-loss "diet", though
it can be used for that purpose. [1]
Some nutritional experts, including some of Sears' former colleagues,
are critical of his conclusions from the scientific evidence,
contending that he has distorted or exaggerated the meaning
of much of the basic research. They point out that no direct
studies to verify his conclusions have been performed. Some
experts consider The Zone a fad diet; others think it "not bad."
[2]
Theory
The diet
centers on a "40:30:30" ratio of calories obtained daily from
carbohydrates, proteins, and fats, respectively. The exact formula
is always under debate, but studies over the past several years
(including a non-scientific study by the PBS documentary show
Scientific American Frontiers) have shown that it can
produce weight loss at reasonable rates. The Scientific American
Frontiers study compared the effectiveness of several popular
'diet' regimes including the Zone; somewhat to the surprise
of the show's staff, the participants on the Zone experienced
the greatest fat loss while simultaneously gaining muscle mass.
Participants also reported the Zone as the easiest regime to
adjust to, i.e. having the fewest adverse affects such as fatigue
or hunger. Most people who report fatigue find that the fatigue
diminishes by day 2 or 3.
"The Zone"
is Sears' term for proper hormone balance. When insulin levels
are neither too high nor too low, and glucagon levels are not
too high, then specific anti-inflammatory chemicals (types of
eicosanoids) are released, which have similar effects to aspirin,
but without downsides such as gastric bleeding. Sears claims
that a 30:40 ratio of protein to carbohydrates triggers this
effect, and this is called 'The Zone.' Sears claims that these
natural anti-inflammatories are heart and health friendly.
Additionally,
the human body in caloric balance is more efficient and does
not have to store excess calories as fat.
The human body cannot store fat and burn fat at the same time,
and Sears believes it takes time (significant time if insulin
levels were high because of unbalanced eating) to switch from
the former to the latter. Using stored fat for energy causes
weight loss.
Another
key feature of the Zone diet, introduced in his later books,
is an intake of the proper ratio of Omega-3
to Omega-6
fatty acids. Dr. Sears is believed to have popularized the taking
of pharmaceutical grade Omega 3 fish oils.[3]
Hormonal
paradoxes
Sears emphasizes
a hormonal paradox contrary to the "low-fat" rationale, namely
that low-fat diets increase the production of the hormone insulin,
causing the body to store more fat. The example proposed by
him is the cattle ranching practice
of fattening livestock efficiently by feeding them lots of low-fat
grain. He and others also point out the supposed irony that
human diets in the West for the last twenty years have been
full of low-fat carbohydrates, yet people are considered more
obese now.
Additionally,
Sears suggests fat consumption as essential for "burning"
fat.
His rationale
is: Monounsaturated fats in a meal contribute to a feeling of
fullness and decreases the rate at which carbohydrates are absorbed
into the bloodstream. Slower carbohydrate absorption means lower
insulin levels which means less stored fat and a faster transition
to fat burning. If the body needs energy and can't burn fat
because of high insulin levels, a person feels tired as their
brain starves and metabolism slows to compensate. This occurs
because the brain runs on glucose
and high insulin levels deplete blood glucose levels. Such condition,
rebound hypoglycemia causes sweet cravings (which just starts
the high-insulin cycle all over again).
Sears describes
a Zone meal as follows: "Eat as much protein as the palm of
your hand, as much nonstarchy raw vegetables as you can stand
for the vitamins, enough carbohydrates to maintain mental clarity
because the brain runs on glucose, and enough monounsaturated
oils to keep feelings of hunger away."
Comparison
to low-carb diets
The Zone
is considered a low-carb diet.[4] It is not as restrictive in total carbohydrate
intake as some of the other low-carbohydrate diets (e.g. the
Atkins diet) that became extremely popular throughout the United
States in 2003 and 2004. Sears claims these other diets miss
the point. According to him, they ignore the importance of hormonal
balance, as well as the influence of dietary balance on digestion
and hormone production.
Specific
cases
Italy
The introduction
of the Zone in Italy began in 1997 by a physician, Aronne Romano
M.D. who applied this nutritional style to patients and athletes.
Since the 2nd edition of the book "Come Raggiungere la Zona"
(The Zone), in 1999, the Chef Memo Romano and his brother Aronne
modified the original recipes and menu to suit the local food
and habits.
Famous
obesity case
Possibly
the most famous case of someone using the diet effectively has
been Mexican Manuel Uribe. After weighing in at around 560 kg
(1234 lbs or over 88 stone) but within a year had lost about
180 kg.[5].
Famous
Followers
Several
Hollywood stars, including Jennifer Aniston, Renee Zellweger,
Cindy Crawford, Charlie Sheen and Tiger Wood are believed to
have followed the Zone diet.
Criticism
The American
Heart Association does not recommend the Zone Diet due to high-protein,
lack of essential nutrients, and little information on long-term
effects.[6] However, characterization of the Zone
diet as 'high-protein' may be inaccurate as the diet is not
intended to increase protein intake beyond a typical American
diet.
Most Vegetarian
or vegan diets, according to Sears, are as far as you can get
from The Zone because they generally utilize very little protein
relative to carbohydrate consumption. This, says Sears, prohibits
the body from operating truly efficiently. As critical as Sears
is of vegetarian and vegan diets, individuals who promote a
vegetarian diet are also very critical of aspects of the Zone
and similar diets. In 2000 Dr. Sears published the Soy zone
where he outlined a zone diet based around soy protein, making
it more vegetarian friendly.
Other nutritional
experts, including some of Sears' former colleagues, are critical
of his conclusions from the scientific evidence, contending
that he has distorted or exaggerated the meaning of much of
the basic research. They point out that no direct studies to
verify his conclusions have been performed.[7]
Official
Zone books
(Partial
list)
- Sears,
Barry (1995). The Zone: A Dietary Road Map. HarperCollins
Publishers.
Sears's initial book on the Zone diet.
- Sears,
Barry (1997). Mastering the Zone. HarperCollins Publishers.
Sears urges substitution of raw vegetables for pastas, breads
and refined sugars. More diagrams and flowcharts than in The
Zone.
- Sears,
Barry (1999). The Anti-Aging Zone. Regan Books. .
Information on meditation, relaxation and exercise in addition
to diet.
- Sears,
Barry; Kotz, Deborah (2000). A Week in the Zone: A Quick
Course in the Healthiest Diet for You. Regan Books.
- Sears,
Barry (2000). The Soy Zone. Regan Books. Discusses
Sears preference for soy protein as part of his balanced eating
program. "The longest-living people in the world" living in
Okinawa, Japan consume much greater amounts of soy protein
and eat smaller meals than most other people.
- Sears,
Barry (2002). The Omega Rx Zone: The Miracle of the New
High-Dose Fish Oil. Regan Books.
- Discusses
"high-dose fish oil;" a newly introduced invented pharmaceutical
grade fish oil that Sears touts as a medical miracle that
will put the eicasonids in balance and reduce inflammation.
Extra virgin olive oil is also promoted for its phytochemicals.
- Sears,
Barry (2005). The Anti-Inflammation Zone: Reversing the
Silent Epidemic That's Destroying Our Health. Regan Books.
References
External
links
|
