|Choosing a Diet for Life.
 pdf File
Professor of Biology, The University of Texas Arlington Texas
Fair is a freelance science writer specializing
in health and nutrition
Obesity will be
the No. 1 killer in the USA by 2005 says the Center for Disease Control
[CDC]. In 1986, a RAND economist reported that one in 200 adults in
America were categorized as extremely obese. Fourteen years later, in
2000, that number had quadrupled to one in 50 and the CDC has reported
that obesity accounted for 400,000 deaths that year. America’s
heartland exemplifies our nation’s problem where more than 60 percent
of people in Texas are overweight or obese, said Emily Palmer, a Texas
Department of Health spokeswoman. The truth is slowly coming to light
about weight gain and why those extra pounds are so hard to lose and,
more importantly, why our diet may be increasing our health risks and
our rate of aging. As obesity becomes epidemic in America and it is
generating a succession of fad diets and new governmental reports and
advice (1,2). Even the federal government is getting into the act as
Health and Human Services Secretary Thompson launched an anti-obesity
advert campaign in March.
Obesity is a
“many-edged” sword with many people making bad choices by eating junk
food, others who eat well past their needs and others that follow high
carbohydrate diets supposedly to try and control their weight. A simple
Google web search using keywords, like diet, health and weight loss,
produces millions of references. There is no shortage of nutritional
advice but, apparently, the advice given for decades has been faulty
and has produced the fat, sad state of our population.
So which diet is
Where did the
Obesity Trail begin?
started with the Battle of Bulge when the frequency of obesity began to
rise. The seemingly logical deduction was that the obese were
overweight because they ate fat, so the ‘Fat Wars’ started as many
nutritionist and doctors, including the American Heart Association
(AHA)(3) endorsed various “low-fat” diets. The simplistic
deduction made sense and the low-fat diets were gobbled up by the
public and were followed by the non-fat products of the 80’s and 90’s
in the name of weight loss and good health.
So Why Are We
Getting Fatter ??
that we eat less fat but we have become caught up in a stranglehold of
the ‘Fat War’ and the casualties are mounting. The populous
suffers from what has been coined, Syndrome X – obesity, high blood
sugar, high triglycerides, high blood pressure, and high cholesterol
(4). Death and diseases that stems form these conditions can be traced
to a poor medical and nutritional advise about what types of foods
maintain a healthy metabolism.
Of course, many
people simply eat too much: They live to eat. The eating lifestyle that
evolved from a daily reality of hard physical labor is generally not
appropriate. Most people in our service based, knowledge economy don’t
burn calories like their ancestors who plowed fields. Compounding the
problem, much of our predominantly sedentary population has
transitioned from cooked-from-scratch food, to pre-processed high-fat,
high carbohydrate, ‘simply-heat’ fast foods.
What should we be
The designers of
today’s popular diets, as well as eminent scientists such as Roy
Walford, M.D. of the Biosphere fame (4) and Dr. G. Reaven, the 1988
Banting Lecturer (5), understand that the advice about good nutrition
given over the past decades– diets high in carbohydrates, low in
protein and fats, is dead wrong and can enhance the risk of heart
disease, diabetes and even cancer (6). The problem with the typical
low-fat diet is that increased carbohydrates counter the reduction in
calories. The combination of high blood sugars produced by the
carbohydrates and low dietary satisfaction from the low level of fat
creates a diet that is difficult to maintain because of cravings and
hunger generate a vicious circle of dieting and binging. Today’s fad
diets, the Atkins(7), South Beach, The Zone, and Perricone Prescription
diets, attack the problem with variations on a theme: restriction of
junk carbs and the consumption of low-glycemic foods those that do NOT
increase circulating blood sugar levels rapidly. These diets have
scientific merit and are useful not only for just losing and
maintaining weight, but also to prevent many of the diseases associated
with aging. The diets are designed to create low and stable blood sugar
levels that are responsive to insulin and which prevents its
overproduction. Insulin is the hormone that functions to help cells
utilize the carbohydrates. Overeaters continually have hyped up insulin
levels. After years of overindulgence their cells eventually become
overexposed and insensitive to insulin – a Type 2 diabetic condition
Most of the
“diets” have a two-week ‘shock’ introduction period of very low
carbohydrate intake. WHY?? The low carbohydrate initiates the
mobilization of body fat and stimulates the process of burning it, and
secondly, and very importantly, it reduces cravings. Foods containing
carbohydrates with a low-glycemic index are added back to the diet
gradually and each person must determine which level of carbs works
best for them. The goal of these diets is to create a metabolic state
where the body works at peak efficiency, and that can be maintained for
the rest of your life by eating controlled carbohydrates and
nutrient-dense foods. The diets classify carbohydrates as “Good”
(low-glycemic index) and “Bad” [high glycemic, ones that release
glucose quickly into the blood] and are therefore restricted. To be
avoided, or minimized, are most processed, “junk” foods that contain
hydrogenated fats or refined sugars, sweet or starchy foods, most
“ready to eat” breakfast cereals, white bread, soft drinks, honey,
candy, solid cooking fats, ice cream and pastries. Foods to be
used sparingly include high-fat meats, cheeses and milk products,
potatoes, pasta, white rice, pizza, spaghetti and certain high glycemic
fruits like bananas and oranges.
Of course, the
body needs both fats and carbohydrates. Certain types of fats, such as
Gamma Omega fatty acids, are essential for energy production, cell
membranes and tissue maintenance. Carbohydrates are valuable as fiber
in all diets, as components of tissues and as a fuel for rapid energy
expenditures. However, unless you are a marathon runner or an active,
growing adolescent, both of whom burn up extra calories, the excess can
lead to dire side effects.
Aging and Diet
show evidence that high blood concentrations of glucose, fatty acids
and low-density lipoproteins derived from the consumption of saturated
fats and high glycemic foods directly contribute heavily to obesity,
diabetes, cardiovascular diseases and the overall declining health of
aging humans (4-8).
Life span may be
largely inherited, but there is evidence that it can be influenced by
diet, exercise and other habits. What you do or don’t eat closely
affects the mechanisms of aging. High blood levels of cholesterol,
triglycerides and low-density lipoproteins increase the risk of
cardiovascular disease: substitution of polyunsaturated fats, such as
vegetable oils, reduces this stress and the risk. Similarly,
maintaining low blood glucose levels improves insulin metabolism
reducing the risks of diabetes. Excess blood sugar can also accelerate
the process of aging in that the sugars can react with protein and the
resulting glycated proteins do not have normal turnover rates. These
damaged proteins tend to accumulate with age resulting in the
stiffening of tissues such as collagen and muscle proteins which
produces wrinkling of the skin, cataracts, decreased strength and most
importantly, stiffening of the artery walls throughout the body.
Dr. Walford, a
world-renowned expert on aging, has published a dietary approach that
stresses restriction of calories by the elimination of both high
glycemic sugar sources and saturated fat, supplemented with many
nutraceuticals (4). Dr. Walford’s elegant, and original, version of the
popular low glycemic lifestyle is based upon scientific experiments
that showed, as long as 65 years ago, that an animal’s lifespan can be
doubled if a optimal nutrient balance is maintained while sharply
reducing calories of both carbohydrates and fats, known as “calorie
restriction” diets. The Mayo Clinic reports that the risk of heart
disease is increased not simply by high fat diets but by the
combination of saturated fat and high glycemic foods (9). The studies
that restrict caloric intake have been shown to extend the lifespan of
all animal species tested not simply by keeping the animals slim and
trim but by reducing the incidence of, and retarding the development
of, a broad spectrum of age-associated pathophysiological diseases.
Calorie restriction has some profound effects upon the body’s
metabolism (10): because blood glucose drops circulating insulin levels
also decline as cells become more responsive to both insulin and
glucose. Body temperature drops, particularly during rest periods and
at the beginning of the program metabolic rate reportedly slows but
readjusts after weeks or months. It is also reported that the
efficiency of energy metabolism improves and there is a reduction in
oxidant production that reduces oxidative damage to cellular DNA,
proteins and lipids in the heart, brain and skeletal muscle. Oxidative
stress damage is the reason that the dietary intake of anti-oxidant
foods and nutraceuticals are a component of all dietary
recommendations. Many scientists who study the aging body believe that
the production of oxygen free radicals during our lifetime produces
many of the outward and tangible signs of aging and that it can be
ameliorated by antioxidant therapy. Scientists suggest that one key to
a healthy existence in old age may be through calorie restriction that
reduces the chronic oxidant production. Oxidants produce damage to
specific cytokines, causes the accumulation of protein aggregates [as
in Alzheimer’s Disease] and glycooxidation products while producing
mitochondrial and nuclear DNA damage.
calorie restricted diet may seem impractical and unacceptable for most
people as a long-term key for human longevity. However, it appears that
the benefits of calorie restriction can be mimicked by a controlled
carbohydrate/controlled fat lifestyle, without the side effects of
starving yourself into health (11). The dietary efforts to mimic the
metabolic effects of calorie restriction show much promise of defeating
the many diet induced, life-shortening diseases. Also, scientists have
shown that synthetic insulin mimetic compounds can overcome obesity and
insulin resistance (12) but have yet to show the effect upon lifespan.
Researchers have also discovered compounds that interact with the
marijuana receptor and block food, alcohol and tobacco cravings. (13)
Riker, a PR spokesman for McDonald’s in Chicago says the hamburger
giant is slimming down its menu because of public pressure to provide
more-healthful food options. Texas public school cafeterias are
curtailing junk foods in line with a new nutrition policy unveiled by
Texas Agriculture commissioner, Susan Combs
It appears that
we are what we eat and that a healthy trip into old age can be a matter
of our own choice.
US Dept of Health & Human Services, and Dept. of Agriculture:
Dietary guidelines for Americans, 5th ed. 2000. Home and Garden
Bulletin No. 232:239. Washington DC, Supt of Documents.
Byers, T. et al., American Cancer Society guidelines. Cancer J. Clin.
52 (2002), pp. 92–119.
American Heart Association (AHA), Low-Fat, Low-Cholesterol Cookbook,
Second Edition : Heart-Healthy, Easy-to-Make Recipes That Taste Great.
1989 & 1997 Clarkson Potter Pub NY
Walford, R. “Beyond the 120 year diet” (2000) Published by Four
Walls Eight Windows. N.Y., London. http://www.walford.com/
Reaven, G.M.. et al. "Banting Lecture 1988. The Role of Insulin
Resistance in Human Disease," Diabetes. (1988) 37(12), 1595-1607
Reaven, G.M., et al. "Hypertension as a Disease of Carbohydrate and
Lipoprotein Metabolism, " American Journal of Medicine, (1989) 87
Kaplan, N.M. "The Deadly Quartet: Upper-Body Obesity, Glucose
Intolerance, Hyper-triglyceridemina, and Hypertension," Archives of
Internal Medicine, (1989)149, 1514-1520.
Atkins, RC “Dr. Atkin’s New Diet Revolution.” (2002) Avon Books NY
Hays, J. et al. “Effect of a high saturated fat and no-starch diet on
serum lipid subfractions in patients with documented atherosclerotic
cardiovascular disease” Mayo Clin Proc. 2003 Nov;78(11):1331-6.
Goddard, I.W. http://users.erols.com/igoddard/cr.htm
Archer, V.E. Med. Hypotheses. “Does dietary sugar and fat influence
longevity? “(2003) 60(6), 924-9.
Air, E. L. et al. “Small molecule insulin mimetics reduce food intake
and body weight and prevent development of obesity.” Nature Medicine.
(2002) 8. 179-183.
J-P Despres American College of Cardiology annual meeting 2004
Rimonabant from Sanofi-Synthelabo).