Obesity Trends and Genes
Charles R. Attwood, M.D., F.A.A.P.

he obesity trend among baby boomers skyrocketed during the closing years of the 20th century. In order to understand this trend, it is necessary to understand that adults do not suddenly become obese. Like most other health risks, obesity usually has its beginnings during childhood, when life-long eating patterns and physical activity habits are established. Parents' lifestyles strongly influence those of their children--who later as adults continue this vicious cycle.

Benji had been coming to our clinic for almost 3 months, always with his aunt, because his mother and father both worked during my office hours. At age 10, he tipped the scales at 140 pounds, approximately double his ideal weight. We learned early in our sessions that he spent 3 hours before the TV each day after school, before his parents got home. His first task, after turning on the TV, was finding a snack -- usually there were cookies, candy, or left-over desserts in the house. After dinner, often brought home by his parents from a fast-food restaurant, he did his homework and played video games before bedtime.

Like his parents, breakfast usually consisted of sweet rolls or a donut, since everyone was in a hurry to leave the house and get to work and school. By lunch time Benji was famished when he got to the school lunch cafeteria. He grabbed french fries and either a hamburger or hot dog, a glass of milk, and whatever dessert he could find. He often traded for and ate his friends' desserts. After school this cycle was repeated. Benji's daily diet is usually rounded out by several high-fat snacks between meals.

Unusual? No, actually Benji's lifestyle is very typical of children his age in America and many other Western nations. A recent report by the Center for Disease Control and Prevention, not unexpectedly, showed that the incidence of severe obesity among children of Benji's age has doubled since 1965. The reason? Inactivity and a diet too high in fat and calories. It's usually a family pattern -- children tend to adopt the eating and activity habits of their parents -- but not an inborn genetic trait. If one parent is overweight, the chances of a child having a weight problem is 40 percent. If both parents are overweight, the child's chances of gaining excessive weight increases to 80 percent. When we finally met Benji's parents,both, as we had predicted, were extremely heavy. Their cavalier attitude about his weight was best expressed by his mother: "We're not really worried;" she said, "he'll probably slim down as he gets older; his cousins did."

Unfortunately, the odds are overwhelming that Benji will, without dietary and exercise intervention, become an overweight adult. Furthermore, slimming down later may not prevent some of the diseases associated with obesity, such as heart disease, stroke, and cancer. A recent study at Tufts University showed that an overweight adolescent will have a increased death rate -- two times greater -- from these diseases before age 70, even if the weight is lost as a young adult. This health risk is never completely abolished. Why should this be the case? One likely reason: excess numbers of fat cells are created during infancy and again during the years around adolescence. These are permanent for the rest of a child's life, always ready to serve for body fat storage. These unfortunate individuals may maintain an excessively high percentage of body fat, regardless of their weight.

Other health risk-factors, such as high blood pressure and elevated cholesterol levels may be silent and unrecognized by parents and peers, but obesity is obvious -- the earliest visible sign of ills-to-come. It should never be ignored. A plant-based diet (see my 4 stages below) and daily physical activity are the necessary corrective measures. Simply reducing the passive time spent in front of a TV screen is an important first step -- surveys show that a typical child of Benji's age in America spends 5 hours a day either watching TV, using a personal computer, or playing video games. Furthermore, the proportion of food commercials for high-fat products (primarily snacks) on children's programs have, in recent years, increased to 41 percent -- up from 16 percent in 1990. High-fat snacks now account for 20 percent of their daily calories, the highest snack-calorie consumption in the world. The French, for example, get about 7 percent of calories from snacks. But restricting calories alone -- even fat-calories -- may not help much. Whereas, reducing dietary fat-calories works very well in correcting elevated cholesterol levels, children need both this and physical activity to control excessive weight.

A $50 billion diet industry in the United States, unwisely bases its programs primarily on caloric restriction; and its failure rate is high. We learned from the China Health Study that the rural Chinese ingest 30 percent more calories than Americans and obesity is rare among them. More physical activity and a plant-based diet with little fat and animal protein seem to be the answer to this paradox. These two factors apparently work together to increase the "resting energy expenditure" (REE). At total rest, or even sleep, a higher REE burns more calories per hour. It's nothing new, no gimmicks; the human body was programmed to behave this way during the Paleolithic period, when children and adults consumed a plant-based diet and were necessarily active. Now, 50,000 years later, with essentially the same genes, we can't trick mother nature.

It's Not The Genes

The common answer given by parents and most health care professionals is disturbing. Because if they're right, nothing can be done about this terrible health risk, which according to former Surgeon General C. Everett Koop, is second only to smoking as a cause of premature death. "It's the genes," they say, "our family is just that way.

So obesity is serious. But let's face it; it's due to lifestyle habits, not genes. Children have eaten more calories and exercised less during the television era. How long does it take for a population to undergo changes in their genes? Thousands of years? Think about it. During the half century between the 1946 and 1997 editions of the Spock book, the genetic pattern of Americans couldn't have changed; yet the portion of our children who are overweight has more than doubled.

The answer is in prevention. Simply limit television to less than 2 hours daily, encourage regular exercise, and gradually shift them to a more plant-based diet of vegetables, fruits, whole grains, and legumes, with less frequent servings -- not every day -- of meat and dairy products. Finally, let's face it. Obesity, the earliest visible sign of poor health, is rare among vegetarian families, who are known to outlive the general population by at least 8 years.

In 1996 the Center For Disease Control and Prevention reported that obesity is far more common today than it was just 3O years ago. Shocking, was their finding that, among children, those that are the most overweight have increased by 100 percent! Aren't we eating less fat; and what about all those selections of fat-free snacks and other foods we're buying like mad? Well, we sometimes forget that all those fat-free foods are not necessarily low in calories. One of my patients admitted to consuming 1,000 calories from a package of fat-free Fig Newtons before she reached the checkout counter of her supermarket.

Portion and serving sizes are getting larger also, not just in the supermarket, but in fast food restaurants. Serving sizes in France, for example, are usually much smaller than in this country. Most Europeans, in fact, are astonished by the size of our hamburgers, pizzas, popcorn, and soft drinks. And predictably, the rate of obesity among the French and Europeans in general is much less than in this country, even though they consume as much or more fat than Americans.

Lost: 22,000 Seats In Yankee Stadium!

One of the most graphic examples of increasing obesity in America is the disappearing seats of a famous baseball park. Yankee Stadium was built during the 1920s. It had about 82,000 seats. After remodeling during the 1970s the seating was only 59,000. During that 50 year period, between Babe Ruth and such baseball greats as Thurman Munson, Ron Guidry, and Reggie Jackson, the American bottom had widened from 14 inches to 19 inches. Patrons at the Mickey Mantle restaurant in New York, where a few of the original seats were installed, have found them to be a tight fit.

Obesity isn't entirely due to excessive dietary fat or even the serving sizes. During the past 30 years, these haven't significantly increased. On the other hand, physical activity has progressively decreased since the mid-1960s. Today's children watch television an average of 5 hours a day. A 1996 report from Harvard in the Archives of Pediatrics showed that obesity was far more common among children watching TV 5 hours daily than among those watching less than 2 hours daily.

Let's face the facts: our creeping obesity is a result of our lifestyle: dietary fat, calories, serving sizes, and inactivity, but not our genes. The father's fat, the mother's fat, the child's fat, and the dog is fat.

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