Unit 9 Body Weight

Units 9 and 10 are not assigned reading. You are only

responsible for material in the powerpoint and lecture.

Key Concepts and Facts Ideal weight and shape should be based on

health Rates of overweight and obesity increasing

world-wide Disease and disorders related to body fat

increasing Location and amount of body fat stores

important to health

Key Concepts and FactsCauses of obesity are complex Influences on development Diet Physical activity Environmental exposures Genetic factors We need to understand calorie need and

balance intake with expenditure.

Body Weight Variations

Regulation of food intake and storage is a very old genetic trait

Underweight was a disadvantage for our remote ancestors

Intake and fat storage were keys to survival Changes in availability of food can explain why

obesity is a major problem

Weight Status Defined?

Culture defines reaction to body sizeEurope of 1400s:pear-shaped adults

were beautifulSome cultures still

consider extra fat sign of health and

beauty

Weight Status Defined?

Today - thinness beyond health boundaries is the standard of beauty

• “Too thin” is the cultural ideal

• Men feel visible body fat is culturally taboo

Body Mass Index BMI is a measure of weight for height to estimate

body fat Ranges of BMI define weights for height

– Underweight– Normal weight– Overweight– Obese

BMI calculation same for males and femalesBMI = [Weight(lbs)]*[703]/[height(in)]2

BMI = [Weight(kg)]/[height(m)]2

BMI

Underweight < 18.5 Normal weight 18.5-24.9 Overweight 25-29.9 Obese 30 or more

US Adults Too Heavy Overweight and obesity is at 67% and rising for adults Obese children aged 6–11 increased from Under 5% in 1965, 7% in 1980, Nearly 18% in 2012. In 2012, more than one third of children and

adolescents were overweight or obese. Obesity is our #1 health problem.

% Obesity by States

World-wide Problem High rates of obesity becoming more

common worldwide Europe - 10-25% of adults are obese

A billion adults worldwide are overweight

Obesity is world public health problem

World Obesity Rates

Obesity and Health

Obesity is not a healthy state Increased risk for:

– Diabetes – Hypertension– Stroke– Heart disease– Certain types of cancer

Life expectancy in overweight/obese adults 3 to 6 years shorter than average

Weight loss lowers blood pressure, LDL cholesterol, risk of diabetes and increases HDL cholesterol

NIH study finds leisure-time physical activity extends life expectancy as much as 4.5 years

Leisure-time physical activity is associated with longer life expectancy, even at relatively low levels of activity and regardless of body weight, according to a study by a team of researchers led by the National Cancer Institute (NCI), part of the National Institutes of Health. The study, which found that people who engaged in leisure-time physical activity had life expectancy gains of as much as 4.5 years, appeared Nov. 6, 2012, in PLoS Medicine

BMI Shortcomings

Weight-for-height and percent body fat do not always correspond

Muscular people can have “obese” BMI Inactive normal BMI people can still have too

much body fat If people retain fluid, BMI may show overweight

but body fat may be low Measures of body fat are more accurate than

weight-for-height

Assessing Body Fat Skinfold thickness measures Bioelectrical impedance analysis (BIA) Underwater weighing Magnetic resonance imaging (MRI) Computerized axial tomography (CT scans) Dual-energy X-ray absorptiometry (DEXA) Whole body air displacement (BOD POD)

Each one has advantages and drawbacks

Some Body Fat Needed

3 to 5% for men and 10 to 12% for women needed for survival

Essential in manufacture of hormones Required component of every cell in the body Provides a cushion for internal organs Low body fat levels:

– delay physical maturation during adolescence– Cause infertility– accelerate bone loss– Accompany starvation

Apples and Pears

Location Important

Pear-shaped: store fat in hips and thighs (better)

Apple-shaped: store fat around the waist (worse)

Apple shape is more common among obese men

Obese young women more often "pears" Obese older women exhibit both shapes

Why “Apple” is bad

Fat cells of central-body fat deposits are larger than those around the hips and “resistant” to insulin

Decrease ability of insulin to lower blood glucose

Insulin and glucose increase over time

Increased Insulin increases triglyceride levels and blood

pressure reduces levels of HDL

increases risk of hypertension and heart disease

promotes the development of diabetes

Body Fat Distribution

Waist size is stronger predictor of heart disease, stroke, and diabetes than BMI (measure horizontally!)

Waist < 40 inches in men or 35 inches in women decreases risk of these diseases

What Causes Obesity?

Obesity occurs when calorie intake exceeds caloric expenditure

Cause is complex– genetics– environmental exposures– diet– physical activity

Heredity

Genetics important in obesity Heredity is 25 to 40% of obesity risk FEW born with errors in metabolism MANY born with traits expressed after

some environmental trigger

Environmental Triggers

Change from active lifestyle to sedentary (off-season for athletes)

Change from home-cooked meals at set times to lots of empty calorie food available

Laid off: change from being busy to at home alone with refrigerator Eating out more: large portion sizes served

Weight Gain and Environment

Chinese Study Shows weight

changes when either a bicycle or motorized vehicle is acquired

Three year study

Diet and Obesity  

Weight gain if – energy in > energy out

Caloric intake up by 340/day Excess fat, protein or carb ——>

increased body fat storesType of calories not importantNumber of calories is!

Unit 10 WEIGHT CONTROLUnit 10 WEIGHT CONTROL

Weight Control: The Myths and

Realities

©2005 Thomson-Wadsworth

Key Concepts and Facts

Effectiveness of weight-control methods gauged by ability to prevent regain

Because a weight-loss product or service is widely publicized doesn’t mean it works

Successful weight control characterized by gradual weight loss

Distressed over Weight

Americans spend over $33 billion annually on weight-loss products and services

Americans are gaining weight faster than they are losing it

Obesity in the United States is on the rise Only 5 to 10% of people who lose weight

keep it off for more than a year

Why We fail at weight loss

A reduction in caloric intake produces weight loss

Fad methods fail, they become too unpleasant Hunger, deprivation, and depression lead to

regain Enjoyable eating and exercise habits are needed

to keep excess weight off Quick weight-loss approaches don’t change

habits

Weight Loss Business

More than 29,000 weight-loss products and services are available

Most either don’t work at all or don’t prevent weight regain

“Quick fix” weight-loss approaches don’t lead to long-term changes in behavior

No laws require a product to be effective.

Truth in labeling Laws

Laws do not keep outrageous claims off television or from being printed in pamphlets, books, magazines, and advertisements

Few companies get caught if they include false or misleading information in weight-loss product ads

Ephedra, or Ma Huang An over-the-counter diet pill and energy-booster A herbal product often in combination with caffeine Serious side effects are related to its use

– Hypertension– Irregular heart beat– Stroke– Heart attack– Seizure– Sudden death

– Finally banned in 2004 after at least

155 deaths

High protein diets

Help people lose weight Pose risks to health Do not help people maintain weight loss Promote loss by decreasing appetite Deprive body of carbohydrates Fats are used for energy instead Use of fat means increased “ketone bodies” Ketone bodies decrease appetite

High Protein Diet?

Protein Diet Limitations

May cause faster weight loss in the first six months of a diet

By one year mark, weight loss is about the same

People revert to more pleasurable, usual diets As soon as carbohydrates are returned to the

diet in normal amounts, appetite returns and weight gain follows

Can They Lose It & Keep It Off?

National Weight Control Registry

Popular myth about weight loss:

everyone who loses weight will eventually gain it back.

This research study has exploded this mythIncludes more than 5,000 individuals who have

lost significant amounts of weight and kept it off for long periods of time.

National Weight Control Registry

Founded in 1993 byDr. James Hill of the University of ColoradoDr. Rena Wing of Brown University and University ofPittsburgh.

Longitudinal prospective study of individuals 18 yearsand older,Successfully maintained a 30 pound weight loss for aminimum of 1 year.

National Weight Control Registry

Successful weight losers report making substantialchanges in eating and exercise habits to lose weightand maintain their losses.

The average registrant has lost approximately 60

pounds and has maintained that loss for roughly 5years.

* Two-thirds of these successful weight losers wereoverweight as children and 60% report a family historyof obesity.

*Extensive histories of overweight andfailed dieting attempts

*Participants used diet and exercise to initially loseweight *About half of registry members report that they

initially lost weight on their own *About half used a formal weight loss program

or assistance from a health care professional. *Both those who lost on their own and those in a

program are meeting RDAs for most nutrients

*

What led to success?

Nearly every subject is currently using dietand exercise to maintain his/her weightloss.

Walking is the most frequent physical activity performed by NWCR members. Weight loss led to significant

improvements in self-confidence, mood andphysical health.

National Weight Control Registry

What’s different about them?

Compared to the general population,are consuming less energy and a lower percentage ofenergy from fat.

*Among this sample of successful weight lossmaintainers, maintenance of weight lossis associated with continued consumption of a healthylow-energy, low-fat diet.

Breakfast Consumption and WeightLoss

*78% reported regularly eating breakfast every day ofthe week.*Only 4% reported never eating breakfast.*No difference in reported energy intake betweenbreakfast eaters and non-eaters*Breakfast eaters reported slightly more physicalactivity than non-breakfast eaters*Eating breakfast is a characteristic common tosuccessful weight loss maintainers and may be a factorin their success.

Does weight loss maintenance becomeeasier over time?Obesity Research, 8: 438-444.For several health-related behaviors, risk of relapse seems todecrease over time.

Registry members who had maintained weight losses for longerperiods of time said that less effort was needed to stay on a diet andto maintain their current weight.

Members who had maintained weight losses for both shorter andlonger periods of time derived equal amounts of pleasure fromexercise, low-fat eating and maintaining their weight losses.

As duration of maintenance increases, the effort required tomaintain seems to decrease.

Enjoy Activity

TheEnd