Modernist-Cuisine-Vol.-1-Small

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One way to determine the number
of calories in a food is to place
a sample of it in a pressure vessel
(or “bomb”), flood the chamber
with pure oxygen to a pressure of
20 bar / 290 psi, then use a red-hot,
electrified platinum wire to set the
food on fire. As it burns, the food
heats water around the bomb, and
a thermometer measures the
temperature increase, which is then
converted into calories. Although
this method is fast and convenient,
it is not especially accurate because
the energy obtained by combusting
the food is not the same as the net
energy obtained by digesting it in
a human body. Some foods, such as
those very high in insoluble fiber,
burn well but pass through the
body largely undigested.
Atkins, Zone, and Spectrum
The Atkins diet coerces the body into ketosis,
a condition in which it burns its fat reserves for
fuel, by restricting carbohydrates to about 20
grams per day in the first two weeks (increased
later on). Whether one is in the beginning weeks
or in the maintenance phase, the plan prohibits
refined sugar, milk, white rice, and white flour.
Eating meat, eggs, cheese, and other forms of
protein is encouraged. Carbohydrate consumption
can be gradually increased as long as weight loss
is maintained. The diet is highly controversial
because of its high fat content and because it is one
of the most restrictive diet plans.
The South Beach Diet is similar to Atkins but
restricts saturated fats more and considers the
glycemic index of a food (the degree to which
a food causes you to release insulin) rather than
grams of carbohydrates.
The Zone diet recommends 30% protein, 30%
fat, and 40% carbohydrate to regulate the amount
of insulin the body releases in response to blood
sugar. It does not restrict calories but does prescribe
portion sizes: protein portions should be about the
size of your palm, and the amount of “good”
carbohydrate (lentils, beans, whole grains, most
fruits and vegetables) should be about twice the
amount of protein consumed. If the carbohydrates
are processed, they should be eaten in smaller
amounts. The Zone limits saturated fats but not
olive oil, canola oil, nuts, and avocado. It gets mixed
reviews from nutrition experts, who like that it is
easy to follow but criticize the scientific rationale.
Developed as part of Dr. Dean Ornish’s program
to reverse heart artery blockages without
surgery, the Spectrum diet is high in fiber and low
in fat. Rather than counting calories, Spectrum
groups foods into how often they can be eaten.
Fruits, vegetables, grains, beans, and legumes
can be eaten until satiety. Nonfat dairy can be
eaten in moderation. All meats, oils, nuts, seeds,
regular dairy, and sugar, along with most processed
foods, should be avoided.
According to Ornish, this eating plan should
result in a diet in which less than 10% of the
calories come from fat. Ornish argues that by
eating whatever quantity we like of low-calorie
foods, we convince our Neolithic, feast-orfamine
metabolisms to continue to work even
though we are consuming few calories. In
addition, the high fiber content slows intestinal
absorption and prevents blood sugar levels from
spiking. Although most medicos endorse the
Spectrum plan, dieters find it hard to stick with
because it is so restrictive.
What works? Many nutrition experts conclude
that all reduced-calorie diets produce short-term
weight loss regardless of their composition. In
a 12-month randomized trial of the Atkins, Zone,
Spectrum, and (low-fat) LEARN diets in overweight,
premenopausal women, those on the
Atkins diet had lost an average of 4.7 kg / 10.4 lb.
Weight losses on the LEARN, Spectrum, and
Zone diets were 2.6 kg / 5.7 lb, 2.2 kg / 4.9 lb, and
1.6 kg / 3.5 lb, respectively.
An earlier, one-year-long randomized trial of
Atkins, Spectrum, Weight Watchers, and Zone
found no statistical difference in the amount of
weight that women lost on each diet. Women on
the more restrictive diets, Atkins and Spectrum,
were more likely to stop following the diet plans
than their peers on Weight Watchers and Zone.
Studies also show that, despite initial weight loss
success, most dieters eventually regain weight.
Which diet is healthiest? As low-carbohydrate
diets soared in popularity, many studies were done
to compare their effects on cholesterol and other
measures with those of conventional low-fat diets.
The studies were relatively small, but nearly all
showed that low-carbohydrate diets reduced total
triglycerides and raised HDL (“good”) cholesterol.
The effect of low-carbohydrate diets on LDL
(“bad”) cholesterol varied from study to study,
representing every possibilityperhaps reflecting
the genetic variability in LDL cholesterol response
to dietary fat.
A few studies included additional blood tests
whose results indicated that C-reactive protein,
which is thought to predict inflammation related
to heart disease, was reduced and vitamin B12
was significantly increased. When the Mediterranean
diet was included in comparisons, it generated
the best insulin responses from volunteers.
A study that compared the Atkins, Spectrum,
Weight Watchers, and Zone diets found that risk
factors for heart disease were reduced as people
lost weight. Risk reduction was not associated
with a particular diet.
CONTROVERSIES
Is Low Fat the Problem?
When it comes to national dietary guidelines, there is
a running theme: the solution becomes the problem.
Nowhere has that theme been more apparent than in the
ongoing war on fat.
For 30 years, the government, food companies, the public
health community, the exercise industry, and plenty of others
have vilified dietary fat as a substance in food that can, among
other things, wreck your heart and make you obese. This
effort has changed the way many millions of people eat.
Store shelves are stocked with literally thousands of often
unappealing low-fat and nonfat foods.
The war has worked, in one sense: fat consumption is down
in the United States for both men and women. Official health
statistics suggest that in the U.S., the percentage of fat calories
in adult diets (top chart at right) has been edging downward,
from about 45% in the 1950s to something closer to 33% by
the early 2000s. That’s pretty good progress.
But here’s the thing: obesity is way up (bottom chart). In
1990, no state in the U.S. had a prevalence of obesity higher
than about 15%; in 2008, only one state had an obesity rate
less than 20%, and 32 states had obesity rates of at least 25%.
These findings lead to a paradox. The low-fat message is
trying to prevent obesity. The data tell us that the low-fat
message worked; we did cut at least some of the fat from our
diet. But obesity has increased, and nobody is sure why.
To explain society’s widening collective girth, observers
have pointed to sedentary lifestyles, the supersizing of food
portions and calorie-packed drinks, and the affordability of
consuming larger quantities of food. Cutting back on fat may
not be enough if we overeat everything else.
A few scientists have advanced a bold suggestion: perhaps
some obesity is actually caused by the low-fat approach. They
argue that demonizing fat only encourages people to switch
to a carbohydrate-heavy diet.
The biological effects of this switch are complex and poorly
understood. Some evidence suggests that consuming excess
carbs throws the body’s insulin metabolism out of whack in
ways that increase hunger, overeating, and ultimately the
accumulation of fat in the body. Another possibility is that
commercially processed low-fat foods simply encourage
people to eat more.
Unfortunately, science just is not yet up to the task of
answering many crucial nutritional questions, such as how
much dietary fat is good for you or whether a low-fat diet will
reduce your weight. Almost every national recommendation
that the public drastically increase or diminish consumption
of a particular dietary component thus effectively encourages
hundreds of millions of people to take a leap of ignorance.
When it comes to the public health problem of obesity, the
leap to low-fat diets has not stopped the epidemic—and it
may even have made the problem worse.
Calorie intake from fa t (%)
Obese and overweight population (% of total)
37
36
35
34
Male
Female
1970 1975 1980 1985 1990 1995 2000 2005
75
70
65
60
55
50
45
40
Male
Female
1970 1975 1980 1985 1990 1995 2000 2005
242 VOLUME 1 · HISTORY AND FUNDAMENTALS
FOOD AND HEALTH 243