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Answer to #1
The prevalence of clinically severe obesity is increasing at an incredibly rapid rate. At this level of obesity, lifestyle changes and modest weight losses can improve disease risks a little, but the most effective treatment is surgery. Two procedures, gastric bypass and gastric banding, have gained wide acceptance. Both procedures limit food intake by effectively reducing the capacity of the stomach. In addition, gastric bypass suppresses hunger by changing production of gastrointestinal hormones. The results are significant: depending on the type of surgery, nearly 50 percent of the excess weight remains lost after 15 years. More long-term studies are needed, but surgery with weight loss often brings immediate and lasting improvements in blood lipids, diabetes, sleep apnea, heart disease, and hypertension.
Because the long-term safety and effectiveness of gastric surgery depend, in large part, on compliance with dietary instructions, nutrition care plays an important role in follow-up treatment. Common immediate postsurgical complications include infections, nausea, vomiting, and dehydration; in the long term, vitamin and mineral deficiencies and psychological problems are common. Lifelong medical supervision is necessary for those who choose the surgical route, but in suitable candidates, the health benefits of weight loss may prove worth the risks.
Answer to #2
a
Answer to #3
Obesity reflects the interaction between genes and the environment. An obesogenic environment includes all of the circumstances that people encounter daily that push them toward fatness. Over the past four decades, the demand for physical activity has decreased as the abundance of food has increased.
People may overeat in response to stimuli in their surroundingsprimarily, the availability of many delectable foods. Most people in the United States find high-kcalorie foods readily available, relatively inexpensive, heavily advertised, and reasonably tastythanks largely to fast food. With around-the-clock access to rich palatable foods, we eat more and more often than in decades pastand energy intakes have risen accordingly. Most alarming are the extraordinarily large serving sizes and ready-to-go meals offered in supersize combinations.
People may be obese, not because they eat too much, but because they move too littleboth in purposeful exercise and in the activities of daily life. Obese people observed closely are often seen to eat less than lean people, but they are sometimes so extraordinarily inactive that they still manage to accumulate an energy surplus. Reducing their food intake further would jeopardize health and incur nutrient deficiencies. Physical activity, then, is a necessary component of nutritional health. People must be physically active if they are to eat enough food to deliver all the nutrients needed without unhealthy weight gain.
Some aspects of the built environment, including buildings, sidewalks, and transportation opportunities, can discourage physical activity. For example, most stairwells of modern buildings are inconvenient, isolated, and unsafe. Roadways often lack sidewalks, crosswalks, or lanes marked for bicycles. The air on roadways can be dangerously high in carbon monoxide gas and other pollutants from gasoline engine emissions. Hot and cold weather also pose hazards for outdoor commuters. In contrast, those with access to health-promoting foods and built environments more easily make healthy choices. Safe, affordable biking and walking areas and public exercise facilities help maintain health and body leanness.
Answer to #4
c
Answer to #5
One popular theory of why a person may store too much fat is the set-point theory. The set-point theory proposes that body weight, like body temperature, is physiologically regulated. Researchers have noted that many people who lose weight quickly regain it all. This suggests that somehow the body chooses a preferred weight and defends that weight by regulating eating behaviors and hormonal actions. After weight losses, the body reduces its metabolic rate. The decrease in metabolic rate after weight loss is greater than would be expected based on body composition alone. This adaptation helps to explain why it can be difficult for an overweight person to maintain weight losses. While set point answers some questions regarding the biology of energy balance, it fails to explain the many other influences contributing to the population's obesity epidemic.
Answer to #6
a
Answer to #7
e
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