Geoffrey Grant.. Professor of Biology, The University of Texas Arlington  Texas 76019-0122     ggrant@uta.edu
Cheri J. 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 best?

Where did the Obesity Trail begin?
The 1970’s 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 ??

Experts suggested 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 eating??

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 (6,7).
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

Research studies 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.
A full-blown 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)
Remarkably, Walt 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.

1.    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.
2.    Byers, T. et al., American Cancer Society guidelines. Cancer J. Clin. 52 (2002), pp. 92–119.
3.    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
4.    Walford, R.  “Beyond the 120 year diet” (2000) Published by Four Walls Eight Windows. N.Y., London. http://www.walford.com/
5.    Reaven, G.M.. et al. "Banting Lecture 1988. The Role of Insulin Resistance in Human Disease," Diabetes. (1988)  37(12), 1595-1607
6.    Reaven, G.M., et al. "Hypertension as a Disease of Carbohydrate and Lipoprotein Metabolism, "  American Journal of Medicine, (1989) 87 (S6A), S2-S6.
7.    Kaplan, N.M. "The Deadly Quartet: Upper-Body Obesity, Glucose Intolerance, Hyper-triglyceridemina, and Hypertension," Archives of Internal Medicine, (1989)149, 1514-1520.
8.    Atkins, RC “Dr. Atkin’s New Diet Revolution.” (2002) Avon Books NY
9.    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.
10.     Goddard, I.W. http://users.erols.com/igoddard/cr.htm (2002)
11.    Archer, V.E. Med. Hypotheses. “Does dietary sugar and fat influence longevity? “(2003) 60(6),  924-9.
12.    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.

13.    J-P Despres  American College of Cardiology annual meeting 2004
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