Obesity in America: Large portions, large proportions

Content provided by the Faculty of the Harvard Medical School

Obesity in America: Large portions, large proportions

Obesity is not a new problem. Forty years ago, 4 of every 10 Americans were overweight or obese. But obesity is a growing problem, and it's growing quickly; today, two of every three Americans need to lose weight. In the 1960s, obesity was an epidemic; today, it's a pandemic.

Why worry?

Most people worry about their weight because they want to look good. Appearance is important, but the consequences of being overweight go well beyond image and self-esteem. Excess body fat has serious consequences for the body's metabolism, including:

• Higher levels of triglycerides

• Higher levels of LDL ("bad") cholesterol

• Lower levels of HDL ("good") cholesterol

• Decreased tissue responsiveness to insulin and higher insulin levels

• Higher blood sugar levels

Ugly numbers are more worrisome than an unflattering profile, for they explain the dramatic increase in illnesses in the United States that cause an enormous burden of death and disability, including:

• Coronary artery disease and heart attacks

• High blood pressure and strokes

• Diabetes mellitus

• Many forms of cancer (see "Obesity and cancer," below)

• Fatty liver, which may progress to cirrhosis

• Osteoarthritis

• Depression and social isolation

It's a sobering picture, and the bottom line is even more staggering. Obesity is a major cause of premature death. The damage is evident in all age groups and with all degrees of overweight, but the toll is heaviest in the heaviest people, and obesity has a greater impact the earlier it occurs. For example, a very obese 25-year-old man can expect to lose 13 years of life — 22% of his life expectancy — due to obesity. A 40-year-old man who is simply overweight may lose more than three years of life, but a 40-year-old man who is obese may lose nearly six years. All in all, obesity and lack of exercise are responsible for about 1,000 deaths in the United States every day. And if present trends continue, obesity will soon overtake smoking as the leading preventable cause of death in America (it is already responsible for a poorer overall health-related quality of life than smoking). Obesity also consumes $39 billion of our badly needed health care dollars each year.

Why the bulge?

Obesity is a complex problem, and scientists don't fully understand the many genetic, biological, and behavioral factors involved. But it's obvious that human genetics and biochemistry take generations to change, while the rate of obesity is skyrocketing, having increased more than 5% since 2000 alone. That magnitude of change can only depend on human behavior — or, in this case, misbehavior.

Diet and exercise are the only behavioral factors that regulate body fat. Both are problems in America. But although fewer than a quarter of us get the exercise we need, we are not any more sedentary than our parents. The culprit, then, must be diet.

The supersizing of America

A 2004 study proved the proposition: Americans are eating more. Researchers at the Centers for Disease Control and Prevention evaluated the caloric consumption of average Americans between 1971 and 2000. For men, the average daily consumption increased from 2,450 to 2,618 calories. That's a jump of 168 calories a day. It may not seem like much, but over the course of a year it will add 17 pounds — and the news is even worse for women, who added 335 calories a day over the 30-year span.

Americans are eating more both at home and away. Portion size and calories consumed increased in all food categories. The greatest increase was in soft drinks, salty snacks, hamburgers, French fries, and Mexican food. From this list, you'll surely predict another important finding: The greatest increase in portions and calories occurred at fast-food establishments.

In 2001, Americans spent more than $110 billion on fast food. The appeal is obvious in today's busy world. But the feeding frenzy does not depend on convenience alone. Advertising feeds the nation's appetite for fast food, with children a major target. It's no surprise that one survey found that 96% of American schoolchildren recognized Ronald McDonald, placing him just behind Santa Claus among fictional icons.

Bargain-priced jumbo servings add to the problem. A typical serving of McDonald's fries contains three times more calories today than when the franchise began. A "regular" soda at Burger King contained 12 ounces in 1954, but a "small" cup contained 16 ounces and a "medium" portion 21 ounces in 2002. And the emphasis on large, relatively inexpensive portions has spilled over to many foods, from cookies to popcorn and sandwiches to steaks.

In one year, an American adult consumes 40 pounds of white bread, 41 pounds of potatoes, 30 pounds of cheese, and 77 pounds of added fats (butter, lard, and cooking oil) — to say nothing of 52 gallons of soda. In all, the Department of Agriculture reports that food consumption rose by 8%, or about 140 pounds per person per year, during the 1990s. Our nation produces about 3,900 calories a day for every man, woman, and child. That's perhaps 50% more food than we need, and the food industry spends $30 billion a year on advertising to be sure it does not go to waste but to waist.

Bigger eyes, bigger stomachs

The industry can lead us to large portions of high-calorie foods, but they can't make us eat them. Or can they?

Each person is ultimately responsible for what he puts in his mouth, but cultural norms are making it harder to make wise choices. Two experiments make the point.

In one study, researchers asked a group of undergraduate students to bring a "medium" portion of various foods to class. In nearly every case, their portions were at least twice as large as the U.S. Department of Agriculture's definition of a medium portion — even though all the students were majoring in nutrition.

The second study showed that people tend to finish their servings, even if they are already full. Volunteers were given macaroni and cheese for lunch in one of four portion sizes that were either measured on a plate or offered in a serving dish. The people who were served larger portions consumed more calories; those who received the largest serving took in 30% more calories than those who got the smallest serving. Even so, the subjects did not report any differences in hunger or fullness after eating.

In our affluent society, food consumption is usually motivated, not by hunger, but by a wide array of cultural and social factors. Large portions and low prices have us eating more, growing fatter, and getting sicker.

Where do you stand?

To find out if you have more body fat than you should, determine your body mass index (BMI). Weigh yourself without clothes and measure your height without shoes. Find your height at the left of the table. Follow across until you hit the box with your weight. Your BMI will be at the bottom of that column.

According to the World Health Organization, a BMI of 25 or more qualifies as overweight and more than 30 indicates obesity. A lean BMI (22 or lower) is best for health, but it's a stringent target; 25 will serve you well. However, even that may not be attainable. As a realistic first step, shoot for the best weight you've maintained for a year after the age of 20. Remember, too, that any step in the right direction will be helpful.

Where's the fat?

If it's around your middle, it's a particular problem. Excess fat is never good for health, but extra fat is much more harmful around the abdomen than in the buttocks and thighs. Men have a propensity toward abdominal obesity (the beer belly), while women tend to accumulate lower-body fat (the pear shape).

To see if you have too much upper-body fat, calculate your waist-hip ratio. With your abdomen relaxed, measure your waist at its narrowest, usually at the navel. Next, measure your hips at their widest, usually at the bony prominences. Finally, divide your waist size by your hip size.

Waist (inches) / Hips (inches) = Ratio

How does your ratio translate into health risk? The chance of suffering a heart attack or stroke increases steadily as a man's ratio rises above 1.0. For women, risk begins to rise about 0.8 — and in both genders, abdominal obesity has major consequences.

What to do?

Despite all the weight loss books, programs, and potions that lighten America's wallet by $33 billion a year, there is only one way to lose weight and keep it off. The math is simple but unforgiving: You must burn more calories than you consume. Sustainable weight loss requires a reasonable diet and regular exercise.

Eat less

Human nutrition is complex, but the mandate for weight loss is not: Reduce your caloric consumption. That means reducing your portion size and choosing your foods wisely. Avoid foods that are high in sugar and/or fat. They are calorie-dense, and they slide down all too easily. Instead, favor fruits, vegetables, and whole-grain products. They are high in fiber, take longer to eat, and may be more filling. For example, compare a medium-size chocolate chip cookie with a medium size apple. They each have about 100 calories (if they are really medium size!). Now consider eating five cookies or five apples; it's obvious that most people can easily knock off the cookies, but few can finish the apples.

For a weight-loss diet, the only thing that counts is the calories you eat. But it's easier to count calories if you favor fruits, vegetables, legumes, whole grains, and low-fat dairy products instead of fast food, whole-fat dairy products, fatty meats, regular soda, and sugary or fatty desserts and snacks. Even though you'll take in fewer calories, you'll get more healthful nutrients. If you add fish, in fact, you'll have an ideal diet.

Exercise more

It's the other half of the weight-loss equation, and it's just as important — but just as neglected — as caloric restriction. The U.S. Surgeon General recommends at least 30 minutes of moderate exercise nearly every day. Just walking two miles a day will substantially reduce a person's risk of heart disease, stroke, diabetes, hypertension, and premature death. It will also burn calories. A 200-pound man will use about 220 calories in 30–40 minutes of brisk walking. In the course of a year, he will take off nearly 30 pounds even without any dietary changes. For faster weight loss, eat less or exercise more.

As far as weight is concerned, exercise has two additional benefits. First, it will keep weight off, accomplishing what all those heavily hyped fad diets fail to achieve. Second, it will take a disproportionately large amount of weight off the abdomen, something abdominal crunches and "spot reducing" schemes never do.

Weighty issues

If caloric restriction and regular exercise are so effective, why is America's waistline expanding at such an alarming rate?

Most individuals can win at the losing game, but cultural norms make it hard to play the game in the first place. In an ideal world, jingles would extol beans and bran instead of burgers and fries. Manufacturers and restaurants would offer reasonable portions and healthy choices. Food labels would list realistic portion sizes. Unit pricing would emphasize prudence, not excess. And we'd all be encouraged to exercise, to use our bodies instead of the TV's remote control.

Social change is slow at best, and reforms will be incomplete at best. But food manufacturers and fast-food companies are beginning to talk about change and educators are starting to take the soda machines and junk food out of our schools. It's a humble beginning, but it is a start. And while we're waiting for the nation to change its ways, each of us should make personal choices that will help us be slimmer and healthier.

Last updated:	September 05, 2008