PE 901/902

It is estimated that inactivity and overweight account for more than over 100,000 premature deaths annually in the U.S.

More than $75 billion per year is spent treating obesity-related health problems.

Overweight and obesity are the 2 most serious and widespread challenges to wellness.

Genetic Factors• It is estimated that genetic contribution to obesity

vary from about 25% to 40% of an individual’s body fat.

• More than 300 genes have been linked to obesity.• Genes influence body size and shape, body fat

distribution and metabolic rate.• Genetic factors also affect the ease with which

weight is gained as a result of overeating and where the body extra weight is added.

• If both parents are overweight, their children are twice as likely to be overweight as children who only have 1 parent overweight.

Physiological Factors•Metabolism and Energy Balance Metabolism – is the sum of all the vital processes by which food energy and nutrients are made available to and used by the body.

Resting Metabolic Rate (RMR) – is the energy required to maintain vital body functions, including respiration, heart rate, body temperature, and blood pressure, while body is at rest.

Physiological Factors RMR – accounts for about 55-75% of daily energy

expenditure. A higher RMR means that a person burns more calories while at rest and can therefore take in more calories without gaining weight.

Basil Metabolic Rate (BMR) -BMR measurements are typically taken in a darkened room upon waking after 8 hours of sleep; 12 hours of fasting to ensure that the digestive system is inactive; and with the subject resting in a reclining position. The more accurate way to measure the minimum amount of energy required to keep your body functioning, including your heart beating, lungs breathing, and body temperature normal.

Physiological Factors• Rules of RMR / BMR

When your age goes up, your BMR and RMR go down.

When your height goes down, your BMR and RMR go down.

When your weight goes down, your BMR and RMR go down.

This means that as you get older, shorter, and lose weight, your BMR and RMR will go down and you will need to eat less or exercise more to maintain your current weight.

Physiological Factors• Calculating RMR / BMR

Physiological Factors Exercise, heredity and muscle mass all have a positive effect on metabolism.

•HormonesHormonal changes at puberty, during pregnancy and at menopause contribute to the amount and location of body fat.

Physiological Factors• Hormones Leptin – a hormone that is thought to be linked to obesity. It is secreted by the body’s fat cells, leptin is carried to the brain, where it appears to let the brain know how big or small the body’s fat stores are. With that information, the brain can regulate appetite and metabolic rate.

•Weight Cycling – Repeatedly losing and regaining weight.

Lifestyle factors• Eating

Eating calorie dense foods more frequently. Eating out more frequently thus eating greater portions.

Studies have found that individuals that eat out consume more calories than individuals that have chose not to eat out.

According to the CDC the average calorie intake by Americans has increase by 250-500 calories per day since 1970 and levels of physical activity have declined.

An additional 150 calories per day can translate into a 15-pound weight gain in one year. (3500 calories corresponds to one pound of body fat)

It takes your stomach approximately 25 minutes after you start eating to tell your brain that it is full.

Lifestyle Factors•Physical Activity Activity levels among Americans are declining, beginning in childhood and continuing throughout the life cycle

During leisure time both children and adults surf the internet, play video games and watch TV rather than participating in physical activities, such as biking, running or yard work.

Doing it Yourself•Cutting caloric intake and increasing

exercise and caloric burning (negative energy balance)

•By creating a negative energy balance of 250-1000 calories/day you’ll produce the recommended weight loss of ½-2 pounds / week.

•For someone who is overweight a reasonable weight loss is 8-10% of body weight over 6 months.

Diet books•Dietary Supplements and Diet Aids Drinks & Food Bars Herbs & Herbal Products

•Weight Loss Programs Overeaters Anonymous (Non-commercial) Weight Watchers, Jenny Craig, Nutrisystem (Commercial)

•Prescription Drugs• Surgery – Gastric Bypass, Liposuction

Eating Disorder – Characterized by severe disturbances in eating patterns and eating-related behavior.

Body Image – The mental representation a person holds about his or her body at any given moment in time, consisting of perceptions, images, thoughts, attitudes, and emotions about the body.

Anorexia Nervosa – an eating disorder characterized by a refusal to maintain body weight at a minimally healthy level and an intense fear of gaining weight or becoming fat; self starvation.• They do not eat enough food to maintain a reasonable body weight.

A BMI of 17.5 or less can sometimes be used to diagnose Anorexia• 1-3 Million Americans have Anorexia and 95% or those are female.• Engage in compulsive behaviors or rituals and use vigorous or

prolonged physical activity to reduce body weight.• When body fat is gone and muscles are severely wasted, the body

turns to its organs in desperate search for protein.• Death can occur from heart failure caused by electrolyte imbalance.• One in 10 women with anorexia dies of starvation, cardiac arrest or

other medical complications.

Anorexia

Bulimia Nervosa – An eating disorder characterized by recurrent episodes of binge eating and then purging to prevent weight gain.• Purging – The use of vomiting, laxatives, excessive exercise,

restrictive dieting, enemas, diuretics or diet pills to compensate for food that has been eaten and that the person feels will produce weight gain.

• During a binge a bulimic person may consume anywhere from 1000 to 60,000 calories within a few hours.

• After the binge it is followed by an attempt to get rid of the food by purging

• The binge-purge cycle places a tremendous strain on the body and can have serious health effects including tooth decay, esophageal damage, and chronic hoarseness, menstrual irregularities, depression, liver and kidney damage and cardiac arrhythmia.

Bulimia