CHAPTER 1 Health Promotionand Weight Control Crisis among Human Beings

"Overweight and obesity are among the most pressing health challenges we face today"

1 Global Epidemic of Obesity

What is obesity? To most people，the term"obesity"means to be very overweight． Health professionals define"overweight"as an excess amount of body weight that includes muscle，bone，fat，and water．"Obesity"specifically refers to an excess amount of body fat． Some people，such as bodybuilders or other athletes with a lot of muscle，can be overweight without being obese．

1.1 Obesity Facts

● Obesity may soon overtake smoking as the world's biggest health problem

● Obesity levels have tripled in the past 20 years

● It can shave an average of 9 years from our lifespan

● Globally there are more than 1 billion overweight adults

● Key causes include consumption of energy dense food high in saturated fat and reduced physical activity

Obesity has reached epidemic proportions globally，with more than 1 billion adults overweight-at least 300 million of them clinically obese-and is a major contributor to the global burden of chronic disease and disability． Obesity is a complex condition，with serious social and psychological dimensions，affecting virtually all ages and socioeconomic groups．

Increased consumption of more energy-dense，nutrient-poor foods with high levels of sugar and saturated fats，combined with reduced physical activity，have led to obesity rates that have risen three-fold or more since 1980 in some areas of North America，the United Kingdom，Eastern Europe，the Middle East，the Pacific Islands，Australasia and China． The obesity epidemic is not restricted to industrialized societies;this increase is often faster in developing countries than in the developed world．（Figure 1-1）

Obesity and overweight pose a major risk for serious diet-related chronic diseases，including type 2 diabetes，cardiovascular disease，hypertension and stroke，and certain forms of cancer． The health consequences range from increased risk of premature death，to serious chronic conditions that reduce the overall quality of life． Of especial concern is the increasing incidence of child obesity．

1.2 Why is This Happening

The rising epidemic reflects the profound changes in society and in behavioral patterns of communities over recent decades． While genes are important in determining a person’ s susceptibility to weight gain，energy balance is determined by calorie intake and physical activity． Thus societal changes and worldwide nutrition transition are driving the obesity epidemic．

As incomes rise and populations become more urban，diets high in complex carbohydrates give way to more varied diets with a higher proportion of fats，saturated fats and sugars． At the same time，large shifts towards less physically demanding work have been observed worldwide． Moves towards less physical activity are also found in the increasing use of automated transport，technology in the home，and more passive leisure pursuits．

1.3 The Extent of the ProbIems

Current obesity levels range from below 5% in China，Japan and certain African nations，to over 75% in urban Samoa． But even in relatively low prevalence countries like China，rates are almost 20% in some cities．（Figure 1-2）

Childhood obesity is already epidemic in some areas and on the rise in others． An estimated 22 million children under five are estimated to be overweight worldwide． According to the US Surgeon General，in the USA the number of overweight children has doubled and the number of overweight adolescents has trebled since 1980． The prevalence of obese children aged 6-to-11 years has more than doubled since the 1960s． The problem is global and increasingly extends into the developing world，for example，in Thailand the prevalence of obesity in 5-to-12 year olds children rose from 12．2% to 15．6% in just two years．（Figure 1-3）

Experts say that obesity among children is a problem that will manifest itself in a big way when these obese/overweight children grow up． If nothing is done to combat the problem we will be facing massive chronic health consequences． According to Prof． Kate Steinbeck，Sydney Royal Prince Alfred Hospital，a huge number of children today may die before their parents because of obesity．

Obesity accounts for 2-6% of total health care costs in several developed countries，some estimates put the figure as high as 7%． The true costs are undoubtedly much greater as not all obesity-related conditions are included in the calculations．

1.4 What Can We Do About It

Effective Weight Control for individuals and groups at risk of developing obesity involves a range of long-term strategies． These include prevention，weight maintenance，management of co-morbidities and weight loss． They should be part of an integrated，multi-sectoral，population-based approach，which includes environmental support for healthy diets and regular physical activity． Creating supportive population-based environments through public policies that promote the availability and accessibility of a variety of low-fat，high-fiber foods，and that provide opportunities for physical activity．

Promoting healthy behaviors to encourage motivate and enable individuals to lose weight by：

● eating more fruit and vegetables，as well as nuts and whole grains;

● engaging in daily moderate physical activity for at least 30 minutes;

● cutting the amount of fatty，sugary foods in the diet;

● Moving from saturated animal-based fats to unsaturated vegetable-oil based fats．

1.5 Who ShouId Lose Weight

Health care providers generally agree that people who have a BMI of 30 or more can improve their health through weight loss． This is especially true for people who are severely obese．

Preventing additional weight gain is recommended if you have a BMI between 25 and 29．9，unless you have other risk factors． Obesity experts recommend you try to lose weight if you have two or more of the following：

● Family history of certain chronic diseases． If you have close relatives who have had heart disease or diabetes，you are more likely to develop these problems if you are obese．

● Pre-existing medical conditions． High blood pressure，high cholesterol levels，or high blood sugar levels are all warning signs of some obesity-associated diseases．

● "Apple"shapes． If your weight is concentrated around your waist，you may have a higher risk of heart disease，diabetes，or cancer than people of the same weight who have a"pear"shape．（Figure 1-4）

Fortunately，a weight loss of 5 to 10 percent can do much to improve health by lowering blood pressure and cholesterol levels． In addition，recent research has shown that a 5- to 7-percent weight loss can prevent type 2 diabetes in people at high risk for the disease．

2 Obesity:Health Consequences

“Obesity is the health problem of the century．”

The prevalence of overweight and obesity is increasing worldwide at an alarming rate in both developing and developed countries． Environmental and behavioral changes brought about by economic development，modernization，and urbanization has been linked to the rise in global obesity． Obesity is increasing in children and adults，and true health consequences may become fully apparent in the near future．

Obesity is a serious illness that can lead to many medical complications． Unfortunately，it is relatively rare for physicians to treat obesity itself because it requires a difficult，long-term process to treat effectively． However，treatment for its complications is done at enormous cost．（Figure 1-5）

Research has shown that as weight increases to reach the levels referred to as“overweight”and“obesity”，the risks for the following conditions also increases：

2.1 Hypertension

One of the most common complications of obesity is hypertension，or high blood pressure． Overweight have at least mildly elevated blood pressure． Obese individuals with hypertension should first be treated with methods in an attempt to reduce their weight． You do not have to reduce to an“ideal”body weight to control the hypertension;rather a 10% reduction of body weight combined with avoidance of excess salt intake can normalize blood pressure and reduce or eliminate the need for blood pressure medications．

2.2 Diabetes

Obesity is the leading cause of diabetes． The risk of diabetes is increased over 53 fold（53 times the“normal”rate）with severe obesity． Of the over 18 million diabetics in the United States（2002 data），about 10% are juvenile onset or Type 1 diabetics． These individuals generally develop diabetes at an early age，usually before the age of 20． This type is not related to obesity． Diabetes developing in childhood，until about 1980，was almost always Type 1;but with the significant increase in childhood obesity，up to 40%（depending on ethnicity，which is also associated with diabetes）have Type 2 diabetes．

The 90% of diabetics that are Type 2，diabetics generally develop their diabetes in their middle years（30's to 60's）． This type of diabetes is almost always associated with obesity and appears to be related to hormonal substances produced by adipose tissue and to the increase amount of blood lipids that occurs in diabetes． In the majority of obese individuals with diabetes，reducing body weight by 10% can eliminate or reduce the need for oral medications or insulin injections．

2.3 EIevated choIesteroI

Elevated cholesterol（hypercholesterolemia）is commonly associated with obesity． On average，every 10 lbs． of excess fat produces 10 mg． of cholesterol per day． In other words，putting on 25 extra lbs． leads to the equivalent of taking in one extra egg yolk per day． Cholesterol levels are determined by both genetics and diet． Two-thirds of your cholesterol level is genetically determined，while the remaining one-third is related to diet． Most people can successfully control their cholesterol by reducing both their fat intake and weight．

2.4 Fatty Liver (NASH)

Fatty liver disease，more formally known as Non-Alcoholic Steato-Hepatitis（“NASH”）is caused by excessive fat deposition in the liver． Excess calorie consumption，can lead to excess fat intake with the fat being stored not only in fat stores，but also in the liver and other vital organs． This excess liver fat results in silent inflammation，usually detected by abnormal liver function tests when a blood panel is performed． In the U．S．，this is the most common cause of abnormal liver function tests，with up to 25% of overweight and obese individuals having this condition． It is estimated that 10 to 20% of individuals with this condition，if untreated，will go on to develop cirrhosis or liver failure during their lifetime． The most effective treatment is weight reduction and increase in physical activity．

2.5 MetaboIic Syndrome (Syndrome X)

This is a scary name． It is commonly found in the obese population，with over 47 million Americans（22%）of the population affected． To be diagnosed with metabolic syndrome，you need three or more of the following criteria：

● Waist circumference>40 inches in men or 35 inches in women．

● Triglycerides>150 mg/dl．

● HDL cholesterol<40 mg/dl in men or<50 in women．

● Blood Pressure>130/85 mm Hg．

● Glucose（fasting）>110 mg/dl．

The most effective treatment of metabolic syndrome is weight reduction;alternatively，the individual conditions are treated with multiple medications and tremendous expense．

2.6 Cancer

Obesity also results in an increased risk of cancer． In females，there is up to a threefold increase in the incidence of breast，uterine，cervical，and ovarian cancer． The risk of endometrial cancer is up to seven times higher． For men，there is an increased incidence of colon and prostate cancer．

2.7 Degenerative arthritis

Degenerative arthritis is more formally known as osteoarthritis． Increased weight causes more wear and tear on the joints． Adipose tissue also produces substances（cytokines）that“destroy”the normal cartilage in joints． If a person loses weight，the wear and tear gradually diminishes and the amount of cytokines released from adipose tissue diminishes． The arthritic destruction of joints that has occurred over the years does not disappear;however，the joint pain will generally diminish since there is less stress and destruction of the joints．

2.8 GaIIstones

Obesity is frequently complicated by gallstones． Approximately 25% of obese individuals have gallstones，often resulting in surgery． The increase in cholesterol that results from obesity is one of the major reasons for the increased incidence of gallstones．

2.9 Heart attacks and strokes

There is an increased incidence of strokes and heart attacks in obese individuals． This increase is both independent of and additive to the increased risk associated with the elevated blood pressure，diabetes，and elevated cholesterol frequently associated with obesity． This increased risk appears to be related to substances produced by adipose that make it easier for blood clots to form． Overall，obesity results in premature death． As a general rule，for every pound over your ideal body weight，subtract one month from your life expectancy！

2.10 SIeep disorders

As people gain weight，many complain that they feel tired all the time and may have problems obtaining a restful sleep． Problems with sleep may be indicative of a severe condition called Pickwickian Syndrome，or sleep apnea． For people with this problem，it becomes progressively more difficult to breathe（especially at night）as their weight increases． These people typically snore severely and have episodes when they stop breathing completely，sometimes for up to one minute at a time． During these apnea periods，heart rhythms may become very irregular，which can lead to a fatal heart attack． People affected with sleep apnea transiently awaken when they resume breathing． This may occur hundreds of times per night，causing the afflicted individual to feel tired the next day． Sometimes，these individuals will fall asleep while sitting in meetings or driving． Sleep apnea is a very serious complication of obesity and requires professional medical attention． The best method of treatment is weight reduction;however，other measures are available to improve the breathing process and help prevent the heart irregularities that frequently complicate this condition．（table 1-1）

3 How do we define obesity and overweight

3.1 Body Mass Index (BMI)

3.1.1 What is BMI

Body Mass Index（BMI）is a mathematical calculation used to determine whether a person is overweight． BMI is a common measure expressing the relationship（or ratio）of weight-to-height． The higher a person’s BMI，the higher the percentage of fat in their body． If your BMI is under 20，you might be underweight． Between 20 and 25，you are probably at a good healthy weight for your height． Being obese and being overweight are not the same condition． A BMI of 30 or more is considered obese and a BMI between 25 and 29．9 is considered overweight．（Figure 1-6）

BMI is calculated by dividing a person’s body weight in kilograms by their height in meters squared（weight [kg] height [m]2）as shown below．

BMI=weight（kg）/height（m）2（SI units）

BMI=weight（lb）× 703/height（in）2

BMI=weight（lb）× 4．88/height（ft）2（Imperial units）

For example，an adult who weighs 70kg and whose height is 1．75m will have a BMI of 22．9．

BMI=70 kg/（1．75 m）2=70/3．0625=22．9

3.1.2 What BMI Levels are Risky

All adults（aged 18 years or older）who have a BMI of 25 or more are considered at risk for premature death and disability as a consequence of overweight and obesity． These health risks increase even more as the severity of an individual’s obesity increases．（table 1-2）

The BMI is more highly correlated with body fat than any other indicator of height and weight． BMI is a reliable indicator of total body fat（table 1-3），which is related to the risk of disease and death． The score is valid for both men and women but it does have some limits．（Figure 1-7）The limits are：

● It may overestimate body fat in athletes and others who have a muscular build．

● It may underestimate body fat in older persons and others who have lost muscle mass．

3.2 Waist Circumference and Waist-to-Hip Ratio (WHR)

3.2.1 Waist Circumference

According to the National Institutes of Health，a high Waist Circumference（WC）is associated with an increased risk for type 2 diabetes，dyslipidemia，hypertension and cardiovascular disease when the BMI is between 25 and 34．9．（A BMI greater than 25 is considered overweight and a BMI greater than 30 is considered obese．）Waist Circumference can be useful for those people categorized as normal or overweight in terms of BMI．（For example，an athlete with increased muscle mass may have a BMI greater than 25-making him or her overweight on the BMI scale - but a Waist Circumference measurement would most likely indicate that he or she is，in fact，not overweight）． Changes in Waist Circumference over time can indicated an increase or decrease in abdominal fat． Increased abdominal fat is associated with an increased risk of heart disease．

Waist circumference is a common measure used to assess abdominal fat content． The presence of excess body fat in the abdomen，when out of proportion to total body fat，is considered an independent predictor of risk factors and ailments associated with obesity．

3.2.2 What Waist Size is Risky

Undesirable waist circumferences differ for men and women：

● Men are at risk that has a waist measurement greater than 40 inches（102cm）．

● Women are at risk that has a waist measurement greater than 35 inches（88cm）．

NOTE：If a person has short stature（under 5 feet in height）or has a BMI of 35 or above，waist circumference standards used for the general population may not apply．

3.2.3 Waist-to-Hip Ratio (WHR)

Waist-to-hip ratio（WHR）is the ratio of a person’s waist circumference to hip circumference，mathematically calculated as the waist circumference divided by the hip circumference． For most people，carrying extra weight around their middle increases health risks more than carrying extra weight around their hips or thighs．

Your waist to hip ratio is an important tool that helps you determine your overall health risk． People with more weight around their waist are at greater risk of lifestyle related diseases such as heart disease and diabetes than those with weight around their hips． It is a simple and useful measure of fat distribution．

Use a measuring tape to check the waist and hip measurements．

● How to measure waist circumference：With a tape measure，comfortably measure the distance around the smallest area below the rib cage and above the umbilicus（belly button）．

● How to measure hip circumference：With a tape measure，comfortably measure the distance around the largest extension of the buttocks．

3.2.4 What is A Good Waist-to-Hip Ratio

For men，a ratio of 0．90 or less is considered safe． For women，a ratio of 0．80 or less is considered safe．

The waist-to-hip ratio（WHR）is a useful parameter for assessing the pattern of fat distribution． Since even in lean individuals men have a higher WHR than do women，the value of WHR associated with increased disease risk is higher for men than for women：WHR>1．0 in men and WHR>0．85 in women are used as indicators of a pattern of body fat distribution associated with increased disease risk．

WHR has been found to be a more efficient predictor of mortality in older people than waist circumference or body mass index（BMI）． If obesity is redefined using WHR instead of BMI，the proportion of people categorized as at risk of heart attack worldwide increases threefold． The body fat percentage is considered to be an even more accurate measure of relative weight． Of these three measurements，only the waist-hip ratio takes account of the differences in body structure． Hence，it is possible for two women to have vastly different body mass indices but the same waist-hip ratio，or to have the same body mass index but vastly different waist-hip ratios．

4 Obesity Causes:Contributing Factors of Obesity

In simplest terms，obesity is the result of a prolonged，large positive energy balance;that is，energy intake has exceeded energy output． A combination of genetic，developmental，and environmental factors has been implicated in the development of obesity．

Weight gain occurs when you eat more calories than your body uses up． If the food you eat provides more calories than your body needs，the excess is converted to fat． Initially，fat cells increase in size． When they can no longer expand，they increase in number． If you lose weight，the size of the fat cells decreases，but the number of cells does not．

Obesity，however，has many causes． The reasons for the imbalance between calorie intake and consumption vary by individual． Your age，sex，and genes，psychological makeup，and environmental factors all may contribute．

4.1 Energy ImbaIance

For most people，overweight and obesity are caused by not having energy balance． Weight is balanced by the amount of energy or calories you get from food and drinks（this is called energy IN）equaling the energy your body uses for things like breathing，digesting，and being physically active（this is called energy OUT）．

Your metabolism dictates how effectively the calories you take in are used． Each person has their own individual daily caloric needs，called the Basal Metabolic Rate． When you take in more calories than your BMR requires，those excess calories turn into excess weight． Think of your incoming and outgoing calories as a checking account that must be balanced． If you do not spend the calories efficiently，the“extra income”is stored in your body as fat． Your fat cells grow and multiply ．．． and you gain weight．

Energy balance means that your energy IN equals your energy OUT． To maintain a healthy weight，your energy IN and OUT don’t have to balance exactly every day． It’s the balance over time that helps you maintain a healthy weight．

● The same amount of energy IN and energy OUT over time=weight stays the same

● More IN than OUT over time=weight gain

● More OUT than IN over time=weight loss

4.2 PhysicaI Inactivity

Many Americans aren’t very physically active． There are many reasons for this． One

reason is that many people spend hours in front of TVs and computers doing work，schoolwork，and leisure activities． In fact，more than 2 hours a day of regular TV viewing time has been linked to overweight and obesity．

Other reasons for not being active include：relying on cars instead of walking to places，fewer physical demands at work or at home because modern technology and conveniences reduce the need to burn calories，and lack of physical education classes in schools for children．

People who are inactive are more likely to gain weight because they don’t burn up the calories that they take in from food and drinks． An inactive lifestyle also raises your risk for heart disease，high blood pressure，diabetes，colon cancer，and other health problems．

4.3 Genes and FamiIy History

Studies of identical twins that have been raised apart show that genes have a strong influence on one’s weight． Overweight and obesity tend to run in families． Your chances of being overweight are greater if one or both of your parents are overweight or obese． Your genes also may affect the amount of fat you store in your body and where on your body you carry the extra fat．

Because families also share food and physical activity habits，there is a link between genes and the environment． Children adopt the habits of their parents． So，a child with overweight parents who eat high-calorie foods and are inactive will likely become overweight like the parents． On the other hand，if a family adopts healthful food and physical activity habits，the child’s chance of being overweight or obese is reduced．

4.4 EnvironmentaI Factors

Genes do not destine people to a lifetime of obesity，however． Environment also strongly influences obesity． This includes lifestyle behaviors such as what a person eats and his or her level of physical activity． Americans tend to eat high-fat foods，and put taste and convenience ahead of nutrition．（Figure 1-8）

Our environment doesn’t always help with healthy lifestyle habits;in fact，it encourages obesity． Some reasons include：

● Lack of neighborhood sidewalks and safe places for recreation．

● Work schedules． People often say that they don’t have time to be physically active given the long hours at work and the time spent commuting back and forth to work．

● Oversized food portions． Americans are surrounded by huge food portions in restaurants，fast food places，gas stations，movie theaters，supermarkets，and even home． Some of these meals and snacks can feed two or more people． Eating large portions means too much energy IN． Over time，this will cause weight gain if it isn’t balanced with physical activity．

● Lack of access to healthy foods． Some people don’t live in neighborhoods that have supermarkets that sell healthy foods such as fresh fruits and vegetables． Or if they do，these items are often too costly．

● Food advertising． Americans are surrounded by ads from food companies． Often children are the targets of advertising for high-calorie，high-fat snacks and sugary drinks． The goal of these ads is to sway people to buy these high-calorie foods，and often they do．

Although you cannot change your genetic makeup，you can change your eating habits and levels of activity． Try these techniques that have helped some people lose weight and keep it off：

● Learn how to choose more nutritious meals that are lower in fat．

● Learn to recognize and control environmental cues（like inviting smells）that make you want to eat when you're not hungry．

● Become more physically active．

● Keep records of your food intake and physical activity．

4.5 PsychoIogicaI Factors

Psychological factors may also influence eating habits． Many people eat in response to negative emotions such as boredom，sadness，or anger．（Figure 1-9）

Most overweight people have no more psychological problems than people of average weight． Still，up to 10 percent of people who are mildly obese and try to lose weight on their own or through commercial weight loss programs have binge eating disorder． This disorder is even more common in people who are severely obese．

During a binge eating episode，people eat large amounts of food and feel that they cannot control how much they are eating． Those with the most severe binge eating problems are also likely to have symptoms of depression and low self-esteem． These people may have more difficulty losing weight and keeping it off than people without binge eating problems．

If you are upset by binge eating behavior and think you might have binge eating disorder，seek help from a health professional such as a psychiatrist，psychologist，or clinical social worker．

4.6 Smoking

Some people gain weight when they stop smoking． One reason is that food often tastes and smells better． Another reason is because nicotine raises the rate at which your body burns calories，so you burn fewer calories when you stop smoking． However，smoking is a serious health risk，and quitting is more important than possible weight gain．

4.7 Age

As you get older，you tend to lose muscle，especially if you’re less active． Muscle loss can slow down the rate at which your body burns calories． If you don’t reduce your calorie intake as you get older，you may gain weight． Midlife weight gain in women is mainly due to aging and lifestyle，but menopause also plays a role． Many women gain around 5 pounds during menopause and have more fat around the waist than they did before．

4.8 Pregnancy

During pregnancy，women gain weight so that the baby gets proper nourishment and develops normally． After giving birth，some women find it hard to lose the weight． This may lead to overweight or obesity，especially after a few pregnancies．

4.9 Lack of SIeep

Studies find that the less people sleep，the more likely they are to be overweight or obese． People who report sleeping 5 hours a night，for example，are much more likely to become obese compared to people who sleep 7-8 hours a night．

People who sleep fewer hours also seem to prefer eating foods that are higher in calories and carbohydrates，which can lead to overeating，weight gain，and obesity over time． Hormones that are released during sleep control appetite and the body’s use of energy． For example，insulin controls the rise and fall of blood sugar levels during sleep． People who don’t get enough sleep have insulin and blood sugar levels that are similar to those in people who are likely to have diabetes．

Also，people who don’t get enough sleep on a regular basis seem to have high levels of a hormone called ghrelin（which causes hunger）and low levels of a hormone called leptin（which normally helps to curb hunger）．

5 Further Understanding of Health Promotion and Weight Control

Health promotion of weight control programs as distinct from fitness to work or health surveillance programs focus on lifestyle and wellness strategies of keeping weight control． They are voluntary and do directly influence healthy weight．

The appropriate health promotions activities of weight control are to offer in a program vary with the different population and personal weight settings． Most programs begin with a fitness component，screening for cardiovascular risk factors，and a health education activity emphasizing fat food cessation and eating health problems．

Evaluation of the impact of worksite health promotion programs is an essential part of their management． Programs that are unpopular or poorly attended should be phased out and people needs and interests should always be taken into consideration before introducing new activities． Even a small company can develop health promotion of weight control programs by sharing or by subsidizing the participation of employees in local health clubs．

The benefits of a well-managed worksite health promotion of weight control programs are many． They appear to succeed in encouraging good health weight habits and improving fitness among employees． Whether they actually reduce overweight and illness rates and increase productivity is not certain，although likely． They certainly improve employee morale and promote positive attitudes． Health promotion programs of weight control in society can be extremely rewarding for all people． Studies are now confirming what has up until now been only believed presumptively． That is，people who do take charge of their health by weight control，eating well，exercising regularly，learning to cope with life stresses，eliminating smoking and drug use，which use alcohol in moderation and who use common sense in the everyday activities，live longer and better． They have fewer days of illness and fewer over weight problems． In short，they lead more productive lives． People support such programs because they are satisfied that they have not only contributed to their personally’ well being，but are reaping solid economic rewards as well．

Health promotion on Weight Control should be：promote positive self-esteem of individuals，families，and communities，help people to understand the weight determinants of health，and to empower people to take control of their body weight．