Christopher Columbus essay

Chapter 10-Body Weight and Its Management

In 2009, about 63% of American adults were overweight or obese.
Overweight-has more fat, muscle, bone, and/or body water than a person whose weight is normal. Not necessarily bad, but people who have too much fat are at risk of being obese.
Obesity-a condition characterized by excessive and unhealthy amounts of body fat.
Prevalence of obesity in the US rose rapidly between 2000-2010 2000-20% or more of the adult population in 22 states were obese. 2010-20% or more of the adult population in EVERY state was obese.
Overweight and obesity are the most common nutritional disorders in the US.
Two risk factors-poor diet and physical inactivity.
Obesity is a chronic metabolic disease that is extremely difficult to treat.

Overweight and Obesity (312)

Adipose cells-cells that store the extra energy from food as triglyceride (fat).

Body Mass Index (312)

Body Mass Index-calculated by dividing weight (kilograms) by height (meters squared), which correlates body weight with risk of developing chronic health conditions.
Estimate: bodyweight in poundsx705, divide by height in inch^2.
Below 18.5-underweight
18.5-24.9-healthy
25.0-29.9-overweight
30-39-obese
40+-morbidly obese
Athletes may register as overweight just because muscle is denser than fat.

The Prevalence of Obesity (313)

Since 1980, obesity rates have doubled in American adults.
2005-06, 34% of Americans 20 or older were obese
Since 1980, prevalence of obesity among children and adolescents who are 2-19 has tripled. 2009-17% of children and adolescents were obese.
Did not meet goal of Healthy People 2010 to reduce excess body fat to 40% of adult population.
WHO says “globesity” is an epidemic. 500 million, or 1/10 adults were obese in 2008.

How Does Body Fat Affect Health? (314)

Greater risk of developing gout (a condition that affects joints), carpal tunnel syndrome (a painful nerve disorder involving the wrist and hand), and sleep apnea (condition in which one stops breathing periodically while sleeping).
More likely to have metabolic syndrome, gallbladder disease, hypertension, diabetes, and heart disease.
Obesity increases risk of cancers in the large intestine (colon), breast (postmenopausal women), uterus, kidney, and esophagus, and more likely to die prematurely.
Excess body fat contributes to more than 90,000 cancer deaths each year.
Surgery is riskier because anesthesia is harder to estimate.
More likely to have fertility problems.
Pregnant women more likely to develop gestational diabetes-form of severe hypertension during pregnancy, as well as babies with birth defects or ones who don’t survive
Causes extra stress on joints likes knees and hips.
Breathing problems (excess fat interferes with lung expansion).
Macrophages multiply excessively and malfunction is people with too much body fat, causing inflammation and damage to blood vessels and heart (heart disease).
Losing 10% of body weight makes a huge difference.
Causes psychological problems as well. Depression, low self-esteem

The Caloric Cost of Living-Energy for Basal (Vital) Metabolism (315)

Metabolism-all chemical changes that take place in cells.
Cells release most calories (50-70%) as heat to maintain body temperature.
Metabolic rate-amount of energy required to fuel cellular activities within a specified time.
Thyroid hormones from thyroid gland regulate metabolism.
Too much thyroid hormone has higher than normal metabolism. Feels warm, nervous and shaky, chronic diarrhea, always loses weight
Too little thyroid hormone has lower than normal metabolism Cold, little energy, constipated, gains weight easily. Can take thyroid pills to balance this out. Vast majority of overweight people have normal thyroid.
Muscle cells use more energy than fat cells, so people with more muscle have higher metabolisms.
Men have more testosterone than women, and usually have higher metabolisms too.
Infants and children have higher metabolic rates than adults.
After 20, metabolic rate declines 1-2% each decade.
Aging people need less energy.

Energy for Physical Activity (316)

Amount of energy needed depends on type of activity, duration, and intensity.
Body size influences energy needed to do activity (heavier people require more energy).
2008 Physical Activity Guidelines for Americans-adults need 150 minutes of moderate aerobic activity per week.
1 in 4 adults were not physically active in 2008.
Physical activities-sports types of exercise, movement for daily living, or spontaneous muscular movements. Sports types-physical activities that are planned and carried out for the purpose of improving health and well being. (swimming, walking, weightlifting). Movements for daily living-various unstructured physical activities such as housework, gardening, walking, and leisure time that are not associated with sports, eating, or sleeping. Americans spend more time on movements for daily living than sports types. Spontaneous muscular movements-fidgeting, maintaining balance, and body posture Also called nonexercise activity thermogenesis (NEAT)
Table on page 317 shows calories spent on each type of exercise.

Energy for the Thermic Effect of Food (317)

Metabolic and physical activity energy needs constitute more than 90% of a person’s energy expenditure.
Thermic Effect of Food (TEF)-when body requires a small amount of energy to digest, absorb, and process the nutrients from food. Less than 10% of total energy.

The Basics of Energy Balance (317)

When caloric intake from food equals calories expended for energy needs, no weight change
When caloric intake is less than expenditures, weight is lost as cells store burned fat.
When caloric intake is more than expenditures, weight is gained as body conserves fat.
Each pound of fat=3500 calories of potential energy.
100 extra calories per day=10 pounds gained in a year.

Body Composition-How Much Fat is Normal? (318)

60% of weight is water
6-22% is protein
3% is minerals
Remaining weight is fat
Average woman has more fat than average man (needed for hormonal and reproductive purposes)
Table 10.4 on 318 shows healthy, overweight, and obese body fat percentages for men/women
50% of person’s fat is located in a layer under the skin (subcutaneous fat)
Rest is stored in muscles, abdomen, thighs, hips, and butt
Cellulite is just subcutaneous fat held in an irregular pattern
Fat cells: Number and size of fat cells increases dramatically during childhood and rapid growth. Fatter adults have normal # of cells, just bigger.

Estimating Body Fat (319)

Methods: hydrostatic weighing, bioelectrical impedance, dual-energy x-ray absorptiometry, air-displacement plethysmography, and skinfold thickness.
Hydrostatic weighing: Body fat is less dense than lean tissue or water. Weigh a person underwater (extra fat makes person lighter) Not practical-equipment not widely available.
Bioelectrical Impedance: Uses electrical currents to estimate percentage of body fat. Fat is poor conductor of electricity, lowers conductivity.

Dual-Energy X-ray Absorptiometry (DEXA or DXA)

Can measure bone density
Very expensive machinery that requires trained x-ray technicians

Air-Displacement Plethysmography

Uses BOD POD to measure person's volume.
Once volume is calculated, fat mass can be calculated.
Quick, involves no exposure to radiation (same with DEXA).

Skinfold Thickness

Not as accurate, but more practical and less costly.
Special calipers measure skinfold thickness precisely.
Measurements should be taken at three or more body sites and averaged together.
Accuracy depends on accuracy of calipers, number of skinfolds measured, and skill of person measuring.
Challenged by some experts because obese individuals have less than half of their body fat under the skin (much is stored in abdomen).

Waist Circumference

Distribution of fat is more important than percentage of fat.
Fat deposits centrally located deep within abdomen tends to cause higher blood cholesterol levels and greater risk of diabetes, hypertension, and heart disease.
Abdominal fat cells (visceral fat) is more likely to release inflammatory compounds into blood than subcutaneous fat in hips and thighs.
These compounds can cause cardiovascular disease and type 2 diabetes.
Apple shaped (men) and pear shaped (women) are signs of high waist circumference.
Tape measurer placed just below ribcage and at top of hipbone can measure waist circumference.
Men with circumference >40 and women>35 have risk of health problems.

What Causes Obesity?-Biological Influences (322)

Genes are responsible for height, fat distribution, body frame size, and the code for weight gain by determining the production of hormones that regulate one's metabolic rate and interest in food.
When one or both parents are obese, they are more likely to have offspring who gain excessive amounts of body fat.
Thousands of years ago fat genes were vital to human survival, so metabolisms burned off excess food energy as body heat, while others had thrifty metabolisms that enabled them to store much of the energy as body fat (more likely to survive during food scarcity).

The Set Point Theory (322)

Because body fat generally does not fluctuate over months, people believe body fat is genetically preset.
Once the level of body fat reaches the set point, the metabolic rate and other internal mechanisms maintain the degree of fatness.
Lean people=lower set points
This is why lean people re-lose weight and fat people regain weight.

Appetite Regulation (324)

Hunger-the physiologic drive to seek and eat food.
Appetite-physiological desire to eat specific foods, which is not the same as being hungry.
Satiety-the feeling that enough food has been eaten to relieve hunger and turn off appetite.
Leptin-a hormone produced by fat cells
Insulin-pancreatic hormone that lowers blood sugar levels.
Leptin and insulin affect the hypothalamus-a region in the brain that regulates eating behavior.
These hormones seem to lose their effectiveness in obese people.

Composition of the Diet (324)

An ounce of fat supplies more than twice the number of calories as an ounce of carbohydrates or protein.
The body stores more fat when the excess off calories is supplied by dietary fat rather than carbohydrates or proteins.
Overweight people should adopt low-fat, high-complex carb diet including fruits, veggies, beans, and whole-grain cereal.
Underreporting caloric intake is common in obese people.
Helpful to keep a daily guide.

Diversity in Health-The Plight of the Pima (323)

July rain transforms Sonora Desert (Arizona) into bountiful food area for Pima Indians collecting mesquite pods, acorns, wolfberries, prickly pears, tepary beans, cholla blossoms.
1930-Pima switched to Western food high in lard (pork fat), refined starches, and sweets.
Soon, 64% of Pima men and 75% of women were obese.
1/3 of men and 1/2 of women had type 2 diabetes-highest known incidence of type 2 diabetes in the world.
Partly due to US Pima's thrifty metabolism.
Partly due to sedentary lifestyle (more labor-saving devices than Mexicans).
Traditional diet was full of amylose, a digestible carbohydrate, as well as gum and mucilages, two forms of soluble fiber, which previously slow digestion and absorption of glucose from small intestine. Scientists are suggesting current US Pima go back to traditional diet.

Environmental, Social, and Psychological Influences (325)

Since the early 1900s, typical portions of many foods have increased. Hershey bar-0.5 ounces to 1.6 ounces. Bagels are three times as big.
It is much easier to get food out of the house now with 24 hour stores and fast food or delivery.
Certain social situations encourage overeating (Thanksgiving, birthdays) or special meals.
Because of technology, we spend most time at work sitting, not moving around.
Being excited, anxious, distressed, depressed, or bored can cause overeating of fatty/sugary foods.

Weight Management (326)

2003-56% of overweight or obese adult Americans were trying to lose weight.
Calorie reduction was main method used.
2009-60% of females and 30% of males in high school were attempting to lose weight.

Weight Reduction Diets (326)

Most try to lower calories while increasing physical activity.

Fad Diets (326)

Fad diets-eating plans that are popular for a time, then quickly lose their widespread appeal.
Atkins diet (1973 and 1998) marketed low carb food but never lasted long.
Common features-gimmicks and caloric restriction.
Gimmick-promotional feature that makes a fad weight loss diet appear to be new, unique, or more effective. Diets based on blood type, diet supplements, secret ingredients.
Overweight people can lose quick weight but gain it back.

Very Low-Calorie Diets (327)

May provide fewer than 800 calories a day and be nutritionally inadequate.
Fasts-diets that provide 400 or fewer calories. Dangerous: accelerates loss of fat and tissue, creating an unhealthy metabolism.
Kidneys eliminate excess water, which causes dramatic weight loss, but returns weeks later.
Dieters must continue cutting calories to stay ahead of metabolism.
Episodes of losing and regaining weight are referred to as yo-yo dieting or weight cycling.

Physical Activity (328)

Physical activity alone is not as effective alone as low-calorie diets.
What appears to be a lack of progress while restricting food intake and exercising may be the result of increase in muscle mass.
Improves appearance, reduced blood pressure and lipid levels.
Individuals whose exercise more than 250 minutes per week may be more likely to maintain weight loss.

Surgical Procedures (329)

Bariatric surgeries (gastric bypass) drastically reduces the capacity of the stomach by creating a small pouch in the upper part of the stomach. People can lose about 60% of weight.
Liposuction-involves vacuuming subcutaneous fat out of the body Most common type of cosmetic surgery in the US. Area is injected with anesthetic or treated with ultrasound0assisted lipoplasty. Hazardous: can cause infections, blood clots, disfigurement, death.

Medications (329)

Orlistat (Xenical) is the only FDA approved prescription drug for weight loss.
Interferes with fat digestion.
Alli-over the counter version of Orlistat.

Alternative Therapies (329)

Acupuncture is an option, but lacks evidence.
Dietary supplements containing chitosan, green tea, chromium picolinate, and hoodia are promoted for weight loss but are not recommended because safety/effectiveness is not clear.
Because these supplements are recommended to be taken along with calorie-restricted diet and exercise, any weight loss might not be result of the medicine.
Table 10.A on p 330 shows common diet supplements.

Strategies for Successful Weight Loss (331)

Safe weight loss plans have 4 characteristics.
They are medically and nutritionally sound.
They include practical ways to engage in regular physical activity.
They are adaptable to one's psychological and social needs.
The can be followed for a lifetime.
They also emphasize nutrient-dense foods and aren't overly restrictive.
No special foods are necessary.
Recommend ways to increase physical activity.
Meets psychological and social needs of overweight persons.
Emphasized behavioral modification, which involves learning to identify behaviors that contribute to one's inability to lose weight..
Table 10.6 on p 333 lists unhealthy behaviors.
Gradual incremental changes are more effective that sudden fad diets.
**A majority of people who have lost weight through nonsurgical methods experience relapse, regaining some or all weight within 4 years because people fail to modify behaviors.

Weight Gain (334)

To gain lean tissue, underweight persons need to consume at least 700 to 1000 calories more per day than they usually eat and perform muscle-building exercises.
They can snack on dried fruit, muffins, granola bars, yogurt and fruit smoothies, peanut butter, and nuts.
Physically active underweight people can eat 35% of their caloric intake from fatty foods.
Avoid excessive amounts of unsaturated fats.

Weight Management (334)

Women who begin a healthy pregnancy should gain 25-35 pounds during the 9 months.
Those who are underweight may gain more, and those who are overweight may gain less.
Table 10.7 shows healthy weight gains during pregnancy for each BMI.
2006-21% of pregnant women gained more than 40 pounds during pregnancy.
Caloric restriction during pregnancy may be hazardous to the developing fetus.
Women within 2 years of birth often are still heavier than women who were not pregnant.
Rule of thumb: Healthy baby doubles its birth weight by 6 months and triples birth weight by its first birthday.
Rapid weight gain during first two years of life is associated with increased blood pressure, BMI, and waist circumference during adulthood.
Breastfed babies are less likely to be obese.
Obese children are more likely to remain obese in adulthood.
Obese children are more likely to have: High blood pressure and cholesterol Type 2 diabetes Breathing problems/sleep apnea/asthma Joint problems Fatty liver disease, gallstones, and heartburn. Poor self-esteem.
By 65, most people have experienced a decline in their lean mass and an increase in their fat mass.
*Contrary to conventional wisdom, many older adults enjoy better health and live longer by being overweight and even obese.
Extra body fat can be source of energy during illness and can provide protection during falls.