The goals of the U.S. Public Health Services’ Healthy People 2010 nutritional objectives include increasing the proportion of adults who are at a healthy weight to 60% compared with the current level of 42% in 1988-1994, and reducing the proportion of adults who are obese to 15% compared with 32.7% adults who are overweight, 34.4% obese, and 5.9% extremely obese in 2005-2006. The goal is about half the current level of obesity. In 2007, 26% of the U.S. population was obese, increased nearly 2% from 2005. Not one state had reached the obesity prevalence goal of 15% established by Healthy People 2010. More men (26.4%) than women (24.8%) were found to be obese. During the past 20 years, the heaviest body mass index (BMI) groups have been increasing at the fastest rates. More depressing is a study that found that if the trend of the past 3 decades continues, possibly every American adult will be overweight 40 years from now. The 2010 goals related to the objectives to attain a healthy weight include increasing the proportion of adults who (1) engage in moderate physical activity for at least 30 minutes per day and (2) perform physical activities that enhance and maintain muscular strength and endurance.
Maintaining a healthy weight is a major goal to reduce the burden of illness and its consequent reduction in quality of life and life expectancy. Obesity and overweight in adulthood go hand-in-hand with chronic diseases, notably hypertension, osteoarthritis, elevated blood cholesterol or triglyceride levels, heart disease, diabetes, gallbladder disease, sleep apnea and respiratory problems, and many cancers. These conditions are associated with significant decreases in life expectancy. Overweight and obesity are the leading cause of cancer, second only to tobacco as a risk facto r for cancer in Americans. The risk for cancer increases even with modest weight gains. Because overweight and obesity seem to contribute to other health problems, their economic impact on the healthcare system is immense. Direct medical costs, which include prevalence, diagnosis, and treatment services, constitute $93 billion, or 9% of the total national medical bill.
The terms overweight and obesity are used interchangeably, but have different meanings. If an individual is very muscular with little fat, a BMI greater than 25 may be acceptable. However, some individuals who are normal or below normal in weight have excess amounts of fat stores. Athletes are usually overweight because of their increased muscle mass, not excess fat. Being overweight is not the same as being fat or obese. Additional muscle tissue aids body functions, but excessive fat interferes with normal body metabolism. A desirable weight depends on the amount and location of body fat and other weight-related medical problems.
Weight distribution is also a factor in predicting health risk. Excess fat in the abdominal area (the “apple-shaped” body), known as android obesity, is characteristic of men, but some women also tend to accumulate more fat around the waist, especially after menopause. Accumulation of fat in the hips or thighs (the “pear-shaped body”), called gynecoid obesity, is typical of women. Any amount of upper body obesity or increased abdominal fat increases health risks. In contrast, lower body or gynecoid obesity is relatively benign and may even be protective. However, patients with this pattern of obesity have more difficulty losing weight and maintaining a healthy weight.
Larger waist measurements indicate accumulating fat stores and are associated with increased health risks. Even normal-weight women face significantly elevated risk of premature death from heart disease, stroke, or cancer with abdominal obesity. Having a proportionately large waist is associated with and accumulation of fat around the heart, liver, and other internal organs. Women greater than 5 feet in height whose waist measurement is more than 35 inches have more health risks, and for men, risk increases at 37 inches with serious concerns with more than 40 inches. If the BMI is greater than 35, waist circumference standards may not apply. Waist-to-height ratio seems to be a good indicator of overall health risks. The waist measurement should be less than half of the person’s height.
Obesity is the result of consistent caloric overconsumption in excess of energy expenditure. The CDC estimates that average daily energy intake increased almost 7% for men and about 22% for women between 1971-2000. American men consume and average of 2600 kcal, and women consume approximately 1850 kcal. This increased intake reflects a consumption level that is conducive for weight gain in inactive individuals. Genetic influence is a significant factor contributing to obesity. Body weight is affected by genes, metabolism, hormones, food choices, behavior, environment, culture, and socioeconomic status. Although genetics and the environment may increase the risk of weight gain, the foods an individual chooses significantly affect body weight. Many factors in American culture have made food more accessible-fast food restaurants, prepackaged food, and soft drinks. Portion sizes also have increased, and more people are eating less often at home. When eating in a restaurant, people tend to consume slightly more than 100 kcal per meal. The problem results in different characteristics and warrants differing treatments.
In some cases, understanding physiological benefits of weight loss can be motivating for some patients. Weight loss is highly desirable in individuals with certain risk factors and advisable for others. A 10% weight loss is associated with a decrease in serum glucose, cholesterol, systolic blood pressure, and uric acid. Other physical symptoms that can be expected to improve with weight loss includeshortness of breath, easy fatigability, fluid retention, gastric disorders, headaches, decreased energy level, decreased sexual interest, joint pains, muscle cramps, elevated pulse rate, sleeping disorders, urinary infection, and varicose veins.
Treatment of obesity has a high level of noncompliance and failure. Weight management is very difficult for most individuals. It is a lifelong commitment to change one’s lifestyle-exercise regularly, make wise food choices, and modify behaviors. Weight loss should be motivated by internal rather than external reasons (“I am doing this for myself,” rather than “I will lose weight for my son’s wedding”). Any treatment for weight loss should always be a serious undertaking with a high level of motivation and long-term commitment. This approach increases chances that the plan will be followed until weight is lost, and that weight loss will be maintained.
One pound of fat equals 3500 kcal. Losing weight can be accomplished by eating fewer kilocalories, increasing activity, or a combination of both. A ½ – to 2-lb per week weight loss is recommended to lose body fat while minimizing muscle loss. To accomplish this goal, food intake must be 500 kcal less than needed per day, which results in loss of 1lb per week. An additional energy expenditure of 500 kcal per day is recommended for the other 1 lb of weight loss. When weight loss is achieved slowly, it is usually more effective and is maintained for a longer period.
Numerous strategies have been implemented to treat overweight and obesity. No one treatment is best for everyone; each modality varies in effectiveness, risk, and cost. Millions of obese individuals have chosen bariatric surgery (surgical procedure on the stomach or small intestine or both for weight reduction), which is very effective for weight loss, but affects the absorption of many nutrients. Drugs and surgical procedures currently being used for weight loss are beyond the scope of this text. A realistic goal regarding the rate and amount of weight loss must be established for each individual trying to reduce weight.
Popular weight reduction diets devised for weight loss are abundant. Although many different plans “guarantee” weight loss, no guaranteed easy cure exists for maintaining a healthy weight. A weight reduction diet needs to be followed for an extended time; it must be appealing and flexible as well as affordable for the individual trying to lose weight. It can be balanced in terms of nutrients, yet hypocaloric. Reducing caloric intake to less than 1200 kcal for women and less than 1400 kcal for men is not recommended because adequate amounts of nutrients are not provided.
Some registered dietitians and scientists believe the low-fat era created an obesity epidemic. The lack of flavor in low-fat foods may have resulted in eating more food and increased caloric intake. This simplistic message to minimize fat intake has some problems. Some types of fat have healthy physiological effects. A certain amount of fat helps individuals feel satisfied longer because fat digestion is slower than carbohydrate or protein. Healthy fats need to be included in a regimen to improve the taste of food and to help increase satiety in addition to their physiological benefits.
Popular diets vary in their nutritional adequacy and consistency with guidelines for risk reduction. Renewed popularity of the low-carbohydrate, high-protein diet resulted in numerous controlled studies to determine effects of various types of diets. The results of several of these studies indicating that low-carbohydrate, high-protein diets are more effective in promoting weight loss and reducing blood lipid levels perplexed the scientific community. However, the long-term effects of this type of diet on health and weight control are unknown. More long-term studies indicate weight is regained when the individual stops following the diet. Some high-fat regimens seem to be unhealthy because of the emphasis on high animal fats and minimal carbohydrates, which include whole-grain products, fruits, and many healthy vegetables. A dietary regimen that stresses meat and high-fat foods but eliminates sugar and most carbohydrates is more successful at helping people lose weight because high-protein foods provide grater satiety.
Evidence is emerging that higher protein diets, even without weight loss, may be beneficial for health. Proteins seem to suppress ghrelin (and appetite-stimulating hormone) better than carbohydrates and lipids. Diets that are considered high fat may cause undesirable cholesterol levels to increase, but weight loss itself usually improves blood lipid levels regardless of the dietary regimen. Another negative side effect of high-protein diets is dehydration.
Different diets work for different people. A reduction diet should include foods from all food groups to provide necessary nutrients. A diet that totally eliminates one category (fat or carbohydrate) or a specific group of foods (fruits or meats) is inadvisable. Indispensable to any weight loss program is a preplanned food allotment with specified times for eating throughout the day to lessen feelings of deprivation and to eliminate excessive food intake. The total amount of food should be divided into at least three feedings. Eating only once or twice a day has been associated with consuming more kilocalories, impulsive snacking, and increased adipose tissue and serum cholesterol. Some “FREE” foods or beverages (foods containing less than 20kcal per serving) may be available for snack periods, but regular mealtimes are important. A diet that requires the least amount of change in usual dietary patterns has better long-term success. A 1200- to 1500-kcal diet is relatively safe; when accompanied by an exercise program, the rate of weight loss is augmented, and muscle mass is maintained.
A weight reduction diet should satisfy the following criteria:
- meets all nutrients needs except energy
- suits tastes and habits
- minimizes hunger and fatigue
- is accessible and socially acceptable
- encourages a change in eating pattern
- favors improvement in overall health
Individuals have indicated several reasons for discontinuing a weight loss regimen:
- trouble controlling food choices
- difficulty motivating oneself to eat appropriately
- using food as a reward
Treatment of obesity is improved when increased energy expenditure occurs along with decreased caloric intake. Exercise alone has a modest effect on weight loss; it positively affects energy metabolism. The initiation of an exercise regimen may lead to with gain in the form of muscle mass, but the health benefits are significant, including improved cardiovascular fitness, improved plasma lipoprotein profile, improved carbohydrate metabolism, increased energy expenditure, and enhanced psychological well-being.
Behavior modification for weight control refers to getting in touch with the reality of which foods are being consumed and in what quantity, and when and why eating occurs. One of the most important components of an effective weight control program is learning new ways of dealing with old habits. Comprehensive behavior-modification programs include diet and exercise programs individually tailored for patients. A team approach including a healthcare provider, a psychologist, a registered dietitian, and the family is more effective in helping the patient make necessary long-lasting changes in food choices and lifestyle behaviors. A food diary for recording amounts and types of food eaten, emotional status, and environmental factors helps to provide new insights to devise strategies for dealing with eating habits.
Although behavior-modification approaches to weight control are helpful, maintaining weight loss remains a major problem. Studies indicate that programs need to be approximately 20 to 24 weeks long and more comprehensive, including relapse prevention training and use of social support systems.