Topic 3.2: Healthy Body Weight

Energy IN

* dietary intakes
* includes all ==foods, beverages, and supplements with a caloric value==

Energy OUT

* resting metabolic rate (RMR)
* thermic effect of food (TEF)
* physical activity EE

What is a healthy body weight?

* science defines a healthy body weight based on ==risk of death from all causes==

Body Mass Index (BMI)

* defines ==average relative weight for height== in people older than *20 years old*
* often correlates with degree of ==body fatness== and ==disease risk==
* calculated by dividing your weight (kg) by your height (m2)

Waist Circumference (WC)

* fat distribution
* least risk: ==<102cm== (males) and ==<88cm== (females)
* most risk: ==≥ 102cm== (males) and ==≥88cm== (females)

Disease Risk Profile

* ex. cholesterol, blood glucose, blood pressure, smoking, physical activity

Drawbacks of BMI

* does not account for ==body composition==
* does not ==distinguish== between ==fat and lean tissue==
* does ==not identify== where ==fat is located==
* ==racial differences== when accessing risk

groups for which BMI does not fit

1. ==Athletes==
* high muscle mass
2. ==Pregnant and lactating women==
* increased weight related to childbearing
3. ==adults over the age of 65==
* BMI based on data collected from younger adults

Population Health Risk

* BMI
* Waist Circumference

Individual Health Risk

* location and distribution of excess fat
* genetics
* socioeconomic factors
* environmental
* mental health

Classification BMI: Underweight

* ≤ 18.5
* ==increased risk== of developing health problems

Classification BMI: Normal Weight

* 18.5-24.9
* ==least risk== for developing health problems

Classification BMI: Overweight

* 25.0-29.9
* ==increased risk== for developing health problems

Classification BMI: Obese Class I

* 30.0-34.9
* ==high risk== of developing health problems

Classification BMI: Obese Class II

* 35.0-39.9
* ==very high== risk of developing health problems

Classification BMI: Obese Class III

* ≥ 40.0
* ==extremely high== risk of developing health problems

Essential Body Fat Required

* men = ==5%==
* women = ==12%== (for reproductive purposes)

How much body fat is ideal?

* healthy range (male) = ==12-20%== of body weight
* healthy range (female) = ==20-30%== of body weight

Body Fat Distribution

* apple shaped: excess ==fat in the chest and stomach== areas puts an individual at *high risk*
* pear shaped: excess fat in the hips, thighs, and buttocks; *less of a risk*
* ==apple shaped distribution== and ==visercal fat== is more related to abdominal obesity
* subcutaneous fat (protective)

Measures of body composition and fat distribution

* ==anthropometry==
* fat fold tests
* waist circumference
* ==Density==
* underwater weighing
* ==Conductivity==
* Bioelectrical impedance
* ==Radiographic Techniques==
* dual energy x-ray absorptiometry (DEXA)

barriers to weight loss

* physical environment
* unpleasantness
* mental distress
* money
* social pressures
* motivation/demoralization
* time (lengthy process)

moderate weight loss

* energy in < energy out
* moderately ==restricts calories==
* balanced diet
* exercise appropriately
* behavioural modification
* draw on energy stores

attainable strategies for weight loss

* set ==goals==
* keep records
* enjoyable foods readily available
* meet ==nutrient needs==

dietary strategies for weight loss

* portion sizes
* meal spacing and timing

limit alcohol:


1. fuel converted to fat and stored
2. slows down the body’s use of fat for fuel
3. more fat stored
4. primarily ==visceral fat==

energy density

measure of the energy provided by a ==food relative to its weight== (kcalories/gram)

nutrients density

relative amount of ==nutrients and fibre per amount of energy== (nutrients/kcalories)

physical activity

* ==30-60 minutes/day==

benefits:

* burn calories, appetite, metabolic rate, stress

popular diets

Pros:

* results in ==weight loss==
* ==body fat== loss
* improvements in ==health status==
* improved ==lipid profiles and insulin levels==

popular diet concerns

* difficult to ==maintain==
* very ==restrictive==
* the real challenge is keeping the weight off
* physical activity

weight loss products

* ==most do not work==
* ex. fitness equipment, surgical procedures, dietary inventions, “diet” foods, herbal products

==consumer protection== on weight loss products

* currently there are ==no laws that protect the consumer==
* companies ==do not== have to show a ==product is effective== before marketing it
* not usually tested for safety
* labels vs. advertisements

fasting and cleanses

* body ==does not become cleansed==
* no long term weight loss
* ==wear and tear== on the GI tract
* weight ==regain==
* increased ==infection==
* preoccupation with food and eating

herbal products

Popular

* ==effectiveness and safety== often not proven
* regulated by natural and non-prescription health products directorate in Canada
* risks: ephedra (ma huang)

who ==benefits== from diet pills?

* BMI of ==30kg/m2==
* ==elevated== disease risk
* medical supervision
* combined with ==diet, exercise, and behavioural therapy==

diet pills: mechanism of action

1. ==suppresses== appetite
2. ==increases== metabolic rate
3. ==inhibit== nutrient absorption

prescribed diet pills

* approved for long-term use in the treatment of obesity
* ==xenical== (orlistat) - partially blocks fat absorption (disables lipase)
* ==saxenda== (liraglutide) - increases satiety hormone
* ==contrave== (naltrexone and bupropion) - controls hunger and cravings

underweight

* BMI below 18.5kg/m2

related to:
* ==genetic tendency== to be thin
* ==poverty==
* ==illness==
* extreme ==restriction of food intake==

==risks== from underweight

* body fat is ==essential==


1. manufacture of hormones
2. required for cushioning of internal organs
3. component of every cell in the body

* infertility
* accelerated bone loss
* delayed physical maturation
* low body fat levels

obesity and health

* life expectancy in overweight/obese adults is ==3-6 years shorter than average==

Even Modest weight loss

* lowers bp
* lowers ldl cholesterol
* lowers risk of diabetes
* increases hdl cholesterol

==risk== from obesity

* ==70%== of people with obesity have at least 1 additional health problem:


1. high blood lipids
2. hypertension
3. heart disease
4. stroke
5. type 2
6. types of cancer
7. liver disease
8. arthritis
9. complications in pregnancy
10. sleep apnea

==mystery== of obesity

* causes of obesity are complex
* genetics
* metabolic
* behavioural
* environmental

==impact== of obesity

* increased healthcare costs
* physical health
* psychological health
* weight bias and stigma
* primary healthcare providers not equipped to support people living with obesity

Edmonton Obesity Staging System

weight loss surgery

* ==bariatric== weight loss surgery
* criteria:

BMI greater than ==40kg/m2==

BMI greater than ==35-40kg/m2== with serious health problems related to their weight

surgery - benefits

* most ==effective method== for weight loss and weight maintenance available
* significant weight loss
* health status improved

type 2 diabetes (blood glucose levels)

hypertension

sleep disorders

lipid profiles

surgery - concerns

* expensive
* post-surgery complications
* cosmetic surgery
* nutrient deficiencies
* psychological problems

bariatric surgery in canada

* ==6000 bariatric surgeries== in Canadian hospitals (2012-2013)
* typical patient: ==female, 40’s, obesity and other conditions== 5% experience complications during hospitalization for the surgery; 6% readmitted to hospital within 30d
* ==short-term increases in use of hospital care== often follow bariatric surgery
* can ==reduce health care use== and costs (i.e. prescribed medication)

liposuction

* fat deposits in ==thighs, hips, arms, back or chin== can be ==partially removed== by liposuction
* ==cosmetic surgery== only
* does not target ==visceral fat==
* fat regained will deposit in other areas of the body