Ch. 6 Weight Management Flashcards
global obesity pandemic
- obesity rates globally have doubled since 1975
- 1.9 billion adults older than 18 years are overweight, and of those, 650 million are considered obese
- data from 2016-2017 on Canadian adults 18yr and older reported
- -27% obese
- -35% overweight
- -40% normal weight
what causes obesity
combination of behaviour, environment, and genetics
- more calories, bigger portions, fast food
- hunger and satiety
- physical inactivity, passive entertainment
- prenatal development factors (hyperplasia, hypertrophy)
- genetics (GAD2 gene, Ob gene)
- emotional influences
- social networks (not fully understood)
- social determinants (eg, lower socioeconomic status, education)
what should I weigh?
-there is no single best weight, but a range of healthy weights
- focus is not on body weight but body composition
- -body mass index (BMI)
- -waist circumference
- -waist-to-hip ration
-need to consider individual risk factors for diseases associated with obesity
body mass index (BMI) and guidelines
- the ration between weight and height
- -BMI = weight (kg)/height(m^2)
- can be used to identify weight-related health risks in populations and individuals 18 years and older
- muscular individuals may be incorrectly categorized as overweight or obese due to greater lean muscle mass
- BMI has limitations (eg, does not reliably reflect body fat)
waist circumference (WC)
- used with BMI as a practical indicator of risk associated with excess abdominal fat
- “apple” shaped bodies have an increased health risk compared to “pear” shaped
- WC above cut-off points is associated with an increased risk of coronary heart disease, type 2 diabetes, and hypertension
was it to hip ration (WHR)
can be a good predictor of mortality in older people
-takes into account differences in body structure
waist measurement at smallest point of the natural waist; hip measurement at widest part of hips
WHR = waist circumference/hip circumference
- high risk for disease: >1 for men; > 0.85 women
- moderately high risk: 0.9-1 men; 0.8-0.85 for women
- lower risk: 0.9 or less for men; 0.8 or less for women
assessing body fat
essential fat: 3-7% of bf in men; 10-15% of bf in women
- helps with physiological function (eg, nerve conduction)
- stored in small amounts in organs and muscles
storage fat: 7-25% for men; 16-35% for women
-helps keep us warm by insulating our bodies
higher body fat in women due to size of bones, muscle mass, fat fluctuation during menstruation, pregnancy, and menopause
skin fold fat measurement
-calliper used to measure the amount of skin fold on various sites
bioelectrical impedance analysis (BIA)
-low-level electric current is passed thru body and opposition to the flow is measured
dual-energy x-ray absorptiometry (DXA)
-x-rays are used to quantify the skeletal and soft tissue components of body mass
hydrostatic weighing
- measures weight of displaced fluid
- muscle has a higher density than water; fat has a lower density
air displacement plethysmography
- total body volume is measured from air displacement
- equation used: density = mass/volume
basal metabolic rate (BMR)
amount of energy the body uses when at complete rest
estimated energy requirement (EER)
the dietary energy intake predicted to maintain energy balance in a healthy adult
-based on age, sex, weight, height, level of activity
resting metabolic rate (RMR)
largest component of daily energy budget
90% of daily expenditure
exercise metabolic rate (EMR)
comes from all types of daily physical activities
10% expenditure
health dangers of excess weight
- higher chance of becoming overweight or obese throughout life
- higher prevalence of T2 diabetes
- greater likelihood of cardiovascular disease risk factors
- increased risk of premature death
- physiological changes equivalent to 20 years of aging (eg, cardiovascular disease, rheumatoid arthritis, liver disease)
impact of excess weight on the body
- Type 2 diabetes: more than 80% of people with type 2 diabetes are overweight
- Heart disease and stroke: people who are overweight are more likely to suffer from high blood pressure and high levels of triglycerides (blood fats), and harmful low-density lipoprotein (LDL) cholesterol, and low levels of beneficial high-density lipoprotein (HDL)
- cancer: obesity contributes to a variety of cancer types
- other problems: knee injuries, spinal disc degeneration, altered immune function, cognitive problems and dementia, fibromyalgia, poor sleep
- premature death: death an average of almost 4 years earlier than those of normal weight; middle aged adults face the highest risk of early death
guide to weight management
- Successful weight management requires a lifelong commitment to healthy lifestyle behaviours
- Weight-management programs must be tailored to an individual’s sex, lifestyle, and cultural, racial, and ethnic values
- Individuals who maintain a healthy weight are highly motivated, educated about nutrition, monitor their food, set realistic goals, are physically active, and have social support
overcoming a weight problem
- Every year, 70% of women and 35% of men are dieting at any given time
- No matter how much weight they lose, 95% gain it back within 5 years
- Most people diet to look better, not because they want to feel better
- The best approach to a weight problem depends on how overweight a person is
overcoming a weight problem: For extreme obesity (BMI 40+)
medical treatment can be performed
-Gastric bypass surgery, laparoscopic gastric banding, gastric bubble
overcoming a weight problem: For moderate obesity (BMI 30-39)
6-month trial of lifestyle therapy, including a supervised diet and exercise
-Initial goal should be 10% reduction in weight
overcoming a weight problem: For overweight (BMI of 25–29)
Cut back moderately on food intake, focus on developing healthy eating and exercise habits
customizing a weight loss plan
One-diet-fits-all approach doesn’t work
- Like food and consume lots of it?; Keep a food diary
- Eat when you’re bored, sad, frustrated, or worried?; Deal with self-esteem or body-image problems
- Graze or nibble on snacks rather than eating regular meals?; Choose low-calorie, low-fat foods; drink water regularly; eat in one place (sitting down)
- Move more often!
diet traps: diet foods
- May be low in fat but high in sugar and calories
- Refined carbohydrates are rapidly absorbed into the bloodstream and raise blood glucose levels, but when they fall, appetite increases
- “Olestra” fat substitute tastes like fat but cannot be digested; Not approved in Canada
diet traps: yoyo syndrome
-On-and-off again dieting can be self-defeating and dangerous
-Repeated cycles of rapid weight loss may change food preferences
-Chronic crash dieters often come to prefer foods that
combine sugar and fat
-Exercising can help overcome the negative effects of
the yo-yo syndrome
-Suggestions for yo-yo dieting: set a danger zone, be
patient, try again
diet traps: very low calorie diets
-Diets that promise to take pounds off fast can be dangerous
-Rapid weight loss is linked with increased mortality
-Up to 50% of weight lost on a very low-calorie diet
may be muscle
-May cause abnormalities in menstrual cycle
-Changes to metabolism make it harder to maintain body weight after dieting
diet traps: popular and fad diets
-Quick and easy weight loss with no effort and usually no physical activity as part of the plan
-High protein and fat, low-carbohydrate diets are not recommended (e.g., ketogenic diet)
-Low-carbohydrate, low-fat diets are also popular
-Signs of a fad diet:
Promises a quick fix
The claim seems too good to be true
Encouraged to limit fruits or vegetables
diet traps: OTC pills
-15% of adults have used weight-loss supplements
–21% women; 10% men
-Women aged 18–34 years are the highest users
-1960s & 1970s: addictive amphetamines were
common
-1990s: fen-phen (appetite depressants)
-Misuse of medication could cause health risks
physical activity - a helpful approach
- Exercise and cutting back calories may be the most effective
- Exercise increases energy expenditure, builds muscle tissue, burns off fat stores, and stimulates the immune system
- Once you start an exercise program, keep it up!
NEAT (non-energy activity thermogenesis)
fidgeting and pacing can be an effective way of burning calories
how to gain weight
-Eat more of a variety of foods rather than more high- fat, high-calorie foods
-If your appetite is small, eat more frequently (e.g., 5– 6 small meals, always eat breakfast)
-Drink juice or milk
-Manage your stress levels: highly stressed people
often have higher levels of NEAT
-Exercise regularly to build up your appetite and your muscle mass
weight discrimination
- Weight bias: negative and false attitudes and beliefs about people who are overweight or obese
- Weight stigma: stereotypes and fallacies that can cause weight discrimination
- Stigma and discrimination toward people who are obese is pervasive and affects psychological and physical health
- Generates health disparities
- Interferes with effective obesity intervention
income and substitution effects on obesity
- Increasing health costs can be directly attributed to the health issues linked to the high prevalence of overweight or obese Canadians
- income effect
- substitution effect
income effect
option of purchasing and consuming things of value
-Purchasing food has increased, which has resulted in higher caloric intakes
substitution effect
consumption of foods that were never readily available, most of which are high in fat and low in quality
provincial and national initiatives
- Improving serving size and nutritional labelling
- Banning certain foods and ingredients
- Regulating sodium consumption
- Limiting access to junk food in schools and community centres
- Designing “walkable” communities, towns, and cities
campus eating
Weight gain can occur for many reasons
-Tend to snack on high-fat, high-calorie, low-nutrient
foods
-First-year students gain an average of 0.89 kg (1.96 pounds) and during the first 11 weeks of university
–1.65 kg (3.64 pounds) gained among students living in residences on campus
-Nutrition initiatives on college and university campuses address the unique nutritional needs of students, administrators, faculty, and recreation departments
unhealthy eating behaviour
- Range from not eating enough to eating too much too quickly
- Media, external pressures, family history, stress, and culture can play a role
- Warning signs of eating disorders should not be ignored
- Skipping meals
- Living on diet foods
- Continuous dieting
body image
how we view ourselves
-often shaped by culture, media
social physique anxiety (SPA)
constantly comparing ones body to other and feeling anxious and dissatisfied with the comparison
body dysmorphic disorder
a psychological disorder where an individual becomes obsessed with their appearance and have and inaccurate image of their body
eating disorders
- Involve a serious disturbance in eating behaviour
- May eat too much or too little
- Concerns over body size and shape that may develop into a compulsion of unhealthy eating behaviours and lifestyles
eating disorder continuum
slide 36
who develops eating disorders
- mostly 14-25 year old
- increasing among men and members of dif ethnic and racial groups
- Male and female athletes are under pressure to maintain ideal body weight or achieve a weight that may enhance their performance
- Both physiological and psychological repercussions occur from eating disorders
anorexia nervosa
-Anorexia means “loss of appetite,” but most individuals with anorexia nervosa are hungry all the time
-Food is an enemy; see themselves as fat or flabby
-Estimated 0.5–4% of women in Canada develop
anorexia nervosa
-Treatment requires medical, nutritional, and behavioural therapies
-May combine restricted diet with exercise or smoking
-Become obsessed with an intense fear of fatness
Anorexia Athletica
- Individuals deal with body image issues by over- exercising
- Believe their self-worth depends on their PA levels and insist that exercising is good for them
- Individuals also often meticulous about their eating habits and may also restrict calories
Bulimia Nervosa
- Repeated eating binges; rapidly consume large amounts of food
- Purging bulimia: induce vomiting or take large doses of laxatives to relieve guilt and control their weight
- Nonpurging bulimia: use other means, such as fasting or excessive exercise, to compensate for binges
binge eating disorder (BED)
- Rapid consumption of abnormally large amounts of food in a relatively short time
- Individuals may feel a lack of control over eating and binge at least twice a week for at least a 6- month period
- Treatment includes education, behavioural approaches, cognitive therapy, and psychotherapy
extreme dieting
Weight never falls below 85% of normal, but weight loss is severe enough to cause uncomfortable physical consequences
- Increased risk of anorexia nervosa
- Believe many misconceptions and myths about food
- Nutritional education may help change this eating pattern
- May need counselling to correct dangerous eating behaviours and prevent further complications
compulsive overeating
- People who cannot stop putting food in their mouths
- Eat fast, eat a lot, eat when they are full
- Many women who eat compulsively view food as a source of comfort against feelings of inner emptiness, low self-esteem, and fear of abandonment
