In terms of its prevalence, obesity is the leading disease in the United States. There is no universally accepted standard for obesity, defined generally as an excess of adipose tissue , but a common rule of thumb classifies people who are more than 20 percent above their desirable weight as obese. By this measure, 30 percent of men and 40 percent of women in America are obese. Although studies show that few of these people will ever recover fully and permanently from the disease, the incidence of obesity in future generations can be reduced.
Adipose tissue is a triumph of evolution. Fat yields 9 calories per gram, while protein, like carbohydrates, yields only 4 calories per gram. Fat also contains much less water than protein does. Therefore, fat is much more efficient for storing excess energy than is protein. Primitive humans, with uncertain food sources, had a great need for excess fat, and their bodies adapted accordingly. Modern humans, with a predictable food supply and a sedentary life-style, are burdened by this vestige of evolution. Although they need some adipose tissue to provide insulation and protect internal organs from injury, modern humans need much less than their primitive ancestors did.
In an attempt to shed excess adipose tissue, many Americans turn from one fad diet to another, and a billion-dollar diet industry has grown up to aid them in their efforts. Nevertheless, the five-year cure rate for obesity is very low. In fact, by comparison, cancer is more curable. The reasons for this are psychological as well as physiological.
From a physical standpoint, losing a pound or two a week for a few weeks is not difficult because most of the loss is in the form of protein and water, and protein carries four times its weight in water. However, protein is also the only source of nitrogen in the body, and when the body loses too much nitrogen, it acts to correct the imbalance by excreting less nitrogen than it takes in. Hence beyond a certain point additional weight loss must come from adipose tissue, which, because of its compactness, takes longer to shed. The body’s tendency to return to nitrogen balance and to protect its energy reserves can be so strong that dieters may stop losing or even gain weight while still expending more calories than they ingest. As a result, they frequently suffer not only from hunger, weakness, and a decreased metabolic rate, but also from depression and inactivity, all of which lead them to abandon their diets. Probably because of numerous psychological factors as well as physiological factors such as increased lipid synthesis, they then tend to regain weight rapidly.
While vigorous attempts to reduce obesity in America should be aimed at all affected, the most successful efforts are likely to be those directed toward children. If the advertising and food industries stop trying to sell high-calorie, nutritionally deficient food to children, and if parents understand that the feeding patterns they impose on their children can determine the adolescent and adult eating habits those children will develop, the future generation may not be as fat as ours is.
Question: The primary purpose of the passage is to
- explain why prevention is the best defense against obesity
- criticize the food and advertising industries for encouraging bad eating habits and thus contributing to the prevalence of obesity in the United States
- recruit volunteers for a national crusade against obesity
- discourage dependency on fad diets as a method for losing weight
- argue that obesity is a genetic disorder that is virtually impossible to cure
Question: By the rule of thumb mentioned in the passage, which of the following would be considered obese?
- I. A 25-pound toddler whose desirable weight is 20 pounds
- II. A large-framed woman weighting 140 pounds whose desirable weight for her height is between 112 and 120 pounds
- III. A 175-pound man who was 25 pounds over his desirable weight and then gained an additional 10 pounds
- II only
- III only
Question: Which of the following, if true, best helps to explain why a greater percentage of women than men in the United States are considered obese by the measure mentioned in the passage?
- The measure is the same for both men and women, but it is normal for women to carry a greater percentage of fat at any weight.
- The average man is heavier than the average woman; therefore, men generally need to gain more weight than women do before they are considered obese.
- There are more women in the United States than there are men.
- Because of the influence of the fashion and film industries, many American women consider themselves obese even though they are not.
- Women burn off fewer calories than men because their bodies contain a lower percentage of muscle, and muscle burns calories at a faster rate than fat.
Question: According to the passage, modern humans do not need to store as much fat as primitive humans because
- modern humans work fewer hours than their primitive forebears did
- the diet of modern humans is higher in protein than was the diet of primitive humans
- modern humans eat more regularly than primitive humans did
- primitive humans had to insulate their bodies from the cold whereas modern humans do not
- the food consumed by modern humans has a higher nutritional value than that consumed by primitive humans
Question: All of the following statements about protein are supported by the passage EXCEPT:
- Gram for gram, foods that are high in protein are lower in calories than foods that are high in fat.
- The body gets all of its nitrogen from protein.
- Nine grams of protein yield the same number of calories as 4 grams of fat.
- Protein is not converted into adipose tissue.
- Five grams of protein carry 20 grams of water.
Question: The author mentions that “cancer is more curable” than obesity in order to
- underscore the point that obesity is the leading disease in the United States
- support the conclusion that it is easier to keep people from becoming obese than it is to cure them once they are
- discourage obese people from trying to lose weight
- demonstrate by analogy that more money should be spent on obesity research
- refute the contention that the causes of obesity are purely physiological
Question: The passage contains information that answers which of the following questions?
- What percent of the total population in the United States is obese?
- What psychological factors cause people to gain weight rapidly once they go off a diet?
- What function does nitrogen perform in the body?
- How is an individual’s desirable eight determined?
- If a snack bar contains 130 calories and 4 grams of fat, what percentage of the calories in the bar come from fat?
Question: The author mentions all of the following as factors that cause obese people to abandon diets EXCEPT
- increased lipid synthesis
- a negative nitrogen balance
- a lower metabolic rate
Question: Which of the following, if it could be demonstrated, would most strengthen the claim that the feeding patterns of children “can determine the adolescent and adult eating habits those children will develop” ?
- The incidence of obesity in children whose parents are both obese is 80 percent.
- Thirty-six percent of infants who are obese during their first half year of life are also overweight between the ages of 20 and 36.
- Excessive weight gain during the teen years can set the stage for a lifetime battle against the bulge.
- Up to 80 percent of youngsters who are fat as 5-year-olds end up fat as adults.
- The average child witnesses more than 15,000 commercials a year for snacks, candy, and soft drinks laden with fat, sugar, and calories.
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