lecture 8: energy balance and healthy body weight Flashcards
BMI
(Weight in KG) / (Height in M)^2; ex., 63.5kg / (1.66m)^2 = 23 BMI
Inherently only reflects height and weight, not body composition
Tends to have a correlation with body fatness unless you’re a bodybuilder
Exceptions*: People who are lean and healthy, very muscular people, people who are <18 and still growing, pregnant women/lactating women, those who are 65+ (27-32 could be okay)
underwight
less than 18.5
healthy BMI
18.5-24.9
overweight
BMI 25-29
obese
BMI 30+
class 1: 30-34
class 2: 35-39.9
class 3: 40+
an epidemic those who are overweight/obese
61.8% men, 46.2% women*****
problems w obesity***
Type 2 Diabetes
Dyslipidemia (abnormal cholesterol; high LDL, low HDL)
HTN, Coronary heart disease
Gallbladder disease
Sleep Apnea
Certain cancers
central obesity
Central Obesity: Fat collecting deep within central abdominal area (visceral fat); ex., people with big stomachs but rock hard abs: it’s because it’s mixed around under the organs vs. subcutaneous pooch
Generally can be determined if you measure waist circumference as well
Increased risk of diabetes, stroke, HTN, CVD, death
apple vs pear shaped
apple shape obesity
Greater risk in men, postmenopausal women, smokers, alcoholics (beer belly)
Keynote feature of central obesity; Can be reduced with physical exercise
pear shape
Women in reproductive years with hips and thighs
waist circumference**
Reflects degree of visceral fatness, most practical indicator* of fat distribution
Where you take it depends on organization; pretty much the same
Take a deep breath then let it out (can’t suck in)
Health Canada: 102cm for men, 88cm for women = increased risk*
Heart and Stroke:
Men: 94cm+ = increased, 102cm+ = substantially increased risk*
Women: 80cm+ = increased, 88cm+ = substantially increased risk*
waist-hip ratio?
gives no more information, benefit, rism than just waist***, useless xtra work
ideal fatness range
12-20 for men, 20-30% for women
Edmonton Obesity Staging System*
This assumes they’re already obese (30+ BMI)
Stage 0: Obese but no risk factors like BP, dyslipidemia, fasting glucose, symptoms
Stage 1: Subclinical, borderline risk factors
Stage 2: Established Diseases related to obesity: HTN, Type 2 Diabetes, Sleep apnea…
Stage 3: Organ damage related to obesity: Heart attacks, strokes…
Stage 4: Severe end-stage disabilities related to obesity; debilitation, impairment, limitations
Know the basics of each of these (none -> signs -> disease -> damage -> 2x damage)
Energy In:
Foods and drinks that you intake; the calories taken in
Any extra calories taken in are stored as Fat; roughly 3500kcal/lb of fat
Energy Out:
Lifestyle and metabolism; percents vary day to day
Basal Metabolism: Sum total of energy expended on all involuntary activities needed to sustain life except for digestion - heartbeat, breathing, skin maintenance
Physical Activities: All voluntary activities and variable element of energy output
Thermic Effect of Food: 5-10% of a meal’s energy is expended while digesting food
Protein has the highest thermic effect of food
Hunger:
Unpleasant/painful sensations that signal a need for food
Roughly 4-6 hours after eating a meal when stomach, SI empties and stomach hormone ghrelin is released but there are MANY more factors
Bloodstream nutrients, meal composition, weather, exercise, hormones, illness
appetite
no hunger, but desire to eat
Leptin
Appetite-suppressing hormone made by adipose that contributes to satiety
If we gain fat = more leptin, less eating; opposite is true
most practical indicator for health
waist circumference
Fasting:
Glycogen stores are exhausted in a day
Protein is broken down to meet brain’s glucose needs; eventually breaks down heart/liver
Ketone bodies are converted from fat as well, most after 10 days of fasting
Healthy person could live 6-8 weeks without eating based on body’s reserves
ketosis
leads to acid-base imbalance
cleanses?
total bs
Low Carb Diets:
Glycogen holds a lot of water: You may just be losing water weight; gained back after eating carbs, desserts tend to be high in carbs as well
Less variety = less interest/appetite, high protein foods also tend to be slow to prepare
Note that minimum carb intake is 130g/day to prevent ketosis, AMDR for carbs is 45-65% kcal
Realistic Calorie Intakes:
Very Low Calorie Diets: <800 kcal/day, generally medically supervised (Dr. B Diet)
Calories are less important than eating a healthy, balanced diet
Spot-reduction*
YOU CANNOT REMOVE FAT AROUND ONE PARTICULAR AREA
surgeries for obesity
It depends and requires extreme obesity
BMI >40 alone or BMI >35 with coexisting disease
Person needs to be fit for surgery; not a cure and requires strict diet, control
Gastric Banding: “Lap-Band”
Silicone donut is put around top of stomach and you can control how tight the band is
Restrictive* method of weight loss; you feel full by restricting how much can be put in stomach
Gastric Bypass (Roux-en-y): Major surgery
Staples are placed to make a smaller, mini stomach; place on SI is cut, placed onto mini stomach so it goes straight to the jejunum (bypasses most of the stomach, duodenum)
It is a restrictive and malabsorptive* method of weight loss
Need to take vitamin supplements since you’re absorbing less
Gastric Sleeve:
You remove most of the stomach except for a banana-width portion of the stomach, both sphincters are left intact however
Restrictive* method of weight loss; can lead to complications, depends on compliance
Vitamin and Mineral deficiencies can occur
Sibutramine
Suppresses appetite; is a serotonin reuptake inhibitor
Orlistat
Inhibits pancreatic, gastric lipase; reduces fat absorbed by the body but in turn may lead to fatty shits
Orlistat
Inhibits pancreatic, gastric lipase; reduces fat absorbed by the body but in turn may lead to fatty shits
Saxenda
Makes you feel less hungry and more full sooner; GLP-1 hormone analog
Saxenda
Makes you feel less hungry and more full sooner; GLP-1 hormone analog
Off-Label Use Drugs
Drugs used for secondary effects; ex., epilepsy medications for weight loss
Ephedrine
Not allowed in Canada for weight loss, energy, bodybuilding, euphoria
eating disorders
- psychological (not a choice)
HIGHER IN WOMEN THAN MEN**
Female Athlete Triad
Combination of disordered eating, amenorrhea, osteoporosis
Disordered Eating: Inadequate nutrition/restrictive dieting + overexercising, weight loss, lack of fat, and extreme bodily stress
Amenorrhea: Absence of periods, caused by the extreme stress, disordered eating, leads to diminished hormones
Osteoporosis: Lowered bone mass and density caused by malnutrition, lack of hormones
Male Athletes
Dancers, figure skaters - aesthetic appeal of being thin, weight classes in sports
“Make weight” practices compromise abilities and can be dangerous;
ex., dropping water weight in order to make a weight class
Muscle Dysmorphia: Psychiatric disorder; obsession with building body mass
Anorexia Nervosa
Distorted body image leading to severe low weight, self-starvation
Persistent energy restriction
Fear of weight gain
Disturbance in body image
Can be restriction type or bingeing/purging type
least prevalent
anorexia nervosa diagnostic criteria**
Persistent restriction of energy and significantly low body weight
Intense fear of weight gain
Disturbance in way one’s body image is tied to self worth, achievements
bulimia nervosa
Characterized by binge eating and purging
Episodes where you binge eat and lose self control
After binge, you compensate with purging: vomiting, laxatives, diuretics, exercise, etc.
Episodes happen once a week for 3 months
bulimia nervosa diagnostic criteria***
Recurrent episodes of binge eating; larger than normal in a small period of time, lack of control
Recurrent inappropriate compensatory behaviours to prevent weight gain
Not just vomiting; also laxatives, diuretics, enemas, fasting, excessive exercise
Binge eating/Compensation occurs on average at least once a week for 3 months
Self-evaluation is influenced by body shape/weight
binge eating disorder
Characterized only by binge eating
Episodes where you binge eat and lose self control
Episodes may lead to psychological stress
Episodes happen once a week for 3 months
Not associated with any compensatory behaviours
most prevalent
binge eating disorder diagnostic criteria
Recurrent episodes of binge eating; way more food than normal and lack of control
Episodes may lead to fasting, fullness, eating alone due to disgust/depression
Distressful episodes occur at least once a week for 3 months
Not associated with purging, fasting, AN, BN
