237 Midterm 1 Flashcards
(139 cards)
1
Q
Define nutrition
A
Interdisciplinary science studying food and health focusing on nutrient and chemical properties of food
2
Q
How long can humans survive without food?
A
Weeks - months (depends on body mass)
3
Q
How long can humans survive without water?
A
3 days
4
Q
Define food security
A
Sufficient supply of safe and nutritious food
No need to steal or scavenge
5
Q
Define food insecurity
A
Limited or uncertain availability of safe and nutritious food
Stealing or scavenging (not socially accepted)
6
Q
Reasons for food insecurity
A
- Poverty
- Absence of supermarkets (environment)
- Limited cooking facilities
- Inexpensive high calorie food access
7
Q
What can food insecurity lead to?
A
- poor quality diet
- Increase of chronic disease risk
8
Q
Highest food insecurity in Canada
A
Northwest Territories (Nunavut 36.7%)
9
Q
Define calorie
A
Unit measure representing energy amount supplied by food (Kilocalorie (kcal, C))
Amount of heat required to raise the temperature of 1kg of water 1 degree
10
Q
Define nutrients
A
Chemical substance used by the body sustains growth and development
11
Q
What are the 6 nutrient categories?
A
- Carbohydrates
- Protein
- Fat
- Vitamins
- Minerals
- Water
12
Q
List the 3 macronutrients
A
- Carbohydrates
- Protein
- Fat
Provide energy
13
Q
List the 3 micronutrients
A
- Vitamins
- Minerals
- Water
Don’t provide energy
14
Q
What do Canadians consume too much of?
A
- Fat
- Sugar
- White flour
- Salt
- Preservatives
- Food colouring
15
Q
What do Canadians consume too little of?
A
- Vitamins
- Minerals
- Fiber
- Protein
- Amino acids
- Phytonutrients
- Antioxidants
16
Q
Causes of inadequate Vitamin A
A
- Reduced liver stores (blood)
- Impaired ability to see in dim light
- Loss vision (long term)
Most common cause of blindness
17
Q
Causes of excessive Vitamin A
A
- Hypervitaminosis
- Nausea, irritability, blurred vison, headache
- Liver damage
- Birth defects (pregnacny)
18
Q
What is DRI?
A
Dietary Reference Intake is
The recommended amount of intake
Lecture 2 pg 13 (graph)
19
Q
What is EAR?
A
Estimated Average Requirement
Estimated average daily intake level that meet half the people in a specific group
Used to calculate RDA
20
Q
What is RDA?
A
Recommended Dietary Allowance
Estimated average daily intake meeting the needs of nearly all people in a specific group
Aim for this amount!
Used most often larger % of population
21
Q
What is AI?
A
Adequate Intake
Average daily adequate intake level
Used if we don’t have EAR and RDA
22
Q
What is UL?
A
Tolerable Upper Intake Level
Highest average daily intake level to pose no health risks (likely)
Don’t exceed this on a daily basis
23
Q
List nutritional deficiencies
A
- Under consumption
Developing countries (e.g. famine) - Over consumption
Typical Western diet (obesity) - Under nutrition
Refined foods, lacks macronutrients
24
Q
Groups at higher risk of becoming malnourished
A
- Infants
- Pregnant
- Elderly
- Ill or recovering from illness
25
Orthorexia Nervosa (clean eating)
- Unhealthy fixation with eating healthy
- Can lead to nutritional deficits
- Falls under avoidant/restrictive food intake disorder (ARFID) in DSM
26
8 concepts of lecture 2
1. Food is a basic need of humans
2. Food provides energy, nutrients & other substances required for health
3. Poor nutrition can result both from inadequate and excessive nutrient intake
4. Malnutrition can result from poor diets, disease, genetic factors or a combination
5. Some groups are at higher risk of becoming malnourished
6. Poor nutrition can influence certain chronic diseases developing
7. Adequacy and balance are key points of a healthful diet (picture pg 18)
8. There are no "good" or "bad" foods
27
Rank highest- lowest (cause of deaths globally)
- Cancer
- HIV/AIDS
- Heart disease
- Neurological diseases
- Diabetes
- Pneumonia
1. Heart disease (33%)
2. Cancer (18%)
3. Pneumonia (4.4%)
4. Neurological diseases (3.9%)
5. Diabetes (2.7%)
6. HIV/AIDS (1.5%)
| USA follows global trend
## Footnote
Canada doesn't follow trend
1. Cancer
2. Heart disease
28
Conditions that contribute to death among adults (under 75)
1. Lifestyle (51%)
2. Environmental exposures (20%)
3. Genetic makeup (19%)
4. Health care (10%)
29
Define risk factors
Condition or behaviour associated with an increased risk of a disease but not proved to be casual
30
List risk factors
- Diet
- Genetics
- Age
- Sedentary lifestyle (sitting disease)
- Smoking and tobacco use
- Stress
- Environmental contaminants
31
Mortality rate attributable to diet
1. High sodium
2. Low whole grain
3. Low fruit
32
How do Western diets promote chronic disease?
Diets high in salt, refined grains (not whole grain), processed meats, refined sugar (e.g. white sugar)
Diets low in fruits, vegetables and fiber
33
Top causes of death =
Nutrition related diseases
34
BMI (Body mass index)
| BMI = kg/(m)^2
< 18.5 = at risk
18.5 - 24.9 = healthy
25 - 29.9 = overweight
> 30 = obesity
| j shaped graph (lecture 3 pg 9)
35
Obesity prevalence in Canadians
Adults:
36.3% overweight + 26.8% obese = 63.1% unhealthy
* greatest increase in 20-39 year olds
Children:'
17% overweight + 9% obese = 26% unhealth (1 in 4)
Calorie intake is just 1 contributor
| Obesity is complex
36
Ancient Diets
| Are they better?
- Claimed by some the healthiest diet is from the Paleolithic era (10,000 years ago)
- Restricts what you eat to food hunter-gathers ate (Stone Age)
- Overeat when food was available, protect them during famine
- Very common to cylce through periods of feasting or famine
- "Feast or famine"
37
Then vs. Now
| Feast and famine
Then:
Root vegetables (high in fibre), nuts, seeds, wild game
Now:
Too much choice contributes to overeating
No famine cycle always in feast
38
Diets have changed but no the body
- Biological processes make it difficult to stay healthy
- Hungry every 4-6 hrs even in the precense of excess fat sotres (can lead to high calorie intake than burned)
- Bodies conserve sodium (leads to high blood pressure)
- Naturally prefer fatty and sweet tasting foods
| conservation of sodium used to be advantageous when consumption was low
39
Taste
Sweet taste
Evolved to associate sweet taste with calories and nutrients safe for consumption
Bitter
Associated with toxic products (many vegetables are bitter causing less consumtion)
* inate thinking
Today, high sugary food consumption then vegetable
40
Nutrition in media problems
- Tight deadlines
- Limited understanding
- Single study
- Report scientific findings prematurely
| Half truths and hype are common
41
Nutrition in media
- Unlawful to state false claims on a product label or advertisement
- Unlawful to use US or Canadian mail systems to sent fradualent products or recieve payments
| Laws rarely enforced with minmal penalties
42
Primary reason for nutrition misinformation
PROFIT
43
Identify nutrition experts
- Registered dietitian
- Nutritionist
## Footnote
Registered dietitian;
- B.Sc. in nutrition
- Intership
- National licensing exam
- Registration (College of Dietitians of Alberta)
- RD
44
Identifying nutrition quakery
- Too good to be true or quick fix
- Testimonials (before and after)
- Make you suspicious of food supply
- Fake credentials
- Elimination of whole food groups
- Use of 'natural'
- Supplements (megadoses)
45
What foods *must* be labelled?
- Foods containing more than one ingredient (mainly processed)
- Dietary supplements
- Claims of "low fat", "low calorie" must display information backing the laim
- Beware of;
Light: *no guidelines*
Low sugar: *no guidelines *
Reduced fat or calories: <25% than original
Fat free: < 0.5g
46
Fat free labelling
Can be labeled "fat free" if < 0.5g fat/serving
47
Foods that dont require labels
- Fresh fruits and vegetables
- Raw, single-ingredient meat, poultry, fish and seafood
- Very small packages (e.g. one bite candy)
- Items with insignificant calories and nutrients (e.g. herbs and spices)
- Food sold at farmer's markets
- Food prepared and packaged in grocery stores (e.g. bakery, salad)
- Alcohol
48
Organic foods
- Financial penalties can be imposed on comapnies that use label inappropriately
- Should be lower in hormones, antibiotics and pesticide and herbicide residues
| Image lecture 4 pg 7
## Footnote
Only products with organic content >/equal to 95% can be labelled organic
49
Plants (organic)
- Grown in soils not treated with synthetic fertilizers, pesticides and herbicides for at least 3 years beofre growing crops
- Can't be fertilized with sewer sludge
- Can't be treated by irradiation
- Can't be grown from genetically modified seeds or ingredients
50
Animals (organic)
- Can't be raised in "factorylike" confinement conditions
- Can't be given antibiotics or hormones to prevent disease or promote growth
- Given 100% organic feed productions
51
'Orgianically grown', 'organically raised' or 'organically produced'
All mean the same as organic and meet the same requirements
52
Multi-ingredient product with 70 - <95% organic content
- Must declare percentage of organic content on label
- **Can't **use organic logo nor claim organic
## Footnote
<70% organic content can only indicate which ingredients are organic in ingredient list
53
Organic vs. Non-organic
| Is organic always healthier?
- Similar nutrient wise (e.g. protein/vitamin)
- Organic fruits and vegetables can have higher antioxidant content
- Organic diets lead to less pesticide exposure
- Avocades, canatloupe, pineapple, broccoli, cabbage and corn have lower levels of pesticides
- Strawberries, spinach, grapes, apple, tomatoes and celery have higher levels of pesticide residues
## Footnote
Cost is not always feasible easier to promote higher fruit and vegetable intake
54
Health claims on foods
- Approved acceptable disease risk reduction or therpeutic claim in Canada
- E.g. oat products and blood cholesterol lowering
-Eligible sources of beta-glucan oat firbre are; oat bran, rolled oats (aka oatmeal) and whole oat flour (Health Canada)
55
Enrichment and fortification
Vitamin and minerals content of food is increased by enrichment and fortiifcation
56
Enrichment
- Pertains only to *refined grain products* where thiamin, riboflavin and iron lost in milling are added
- Bread, cormeal, pasts and cracker from refined grains must use enriched flours by producers
## Footnote
**Bran** - Fiber rich outerlayer, protects seed, Vitmin B and trace minerals
**Endosperm** - Middle layer, carobohydrates and proteins
**Germ** - Small nutrient rich core, antioxidants, vitamin B & E and healthy fats
57
Foritfication
Addition of a vitamin or mineral not normally found in the food
58
Ingredient label
- **ALL ingredients must be listed in descending order of weight**
- Ingredients causeing allergic reactions must be listed on ingredient label
59
Food additives (label)
- Must be listed
- 3000 chemicals are added to enhance flavour, colour, texture, cooking properties, shelf life or nutrient content
- Food additives with "GRAS" (generally recognized as safe) can be used without approval (e.g. sodium chloride, sucrose, cornstarch, many vitamins/minerals)
- New additives must be Health Canada approved before use
60
What are irradiated foods?
| Not present in organics
- High dose radiation to kill unwanted features or ingredients
1. Must contain radura symbol (lecture 4 pg 20)
2. Uses;
Prevent sprouting
Delay ripening
Kill insects/mold/bacterica (good use) (e.g. Wheat, flour, spices, ground beef)
3. Foods don't retain radioactive particles
4. Doses: 10-20x higher than lethal dose in humans
61
Dietary suplement labeling
- Must be labelled
- Labels can't claim products treat, cure or prevent disease
- Not classified as a drug, no vigorous testing
- Product liecense NPN (natural product number) needed to be sold in Canada (all natural health products)
## Footnote
Specific labelling and packaging requirements must be met for licensing with good manufacturing practices
62
What to eat?
| Not born knowing
- Generally humans don't seek nutrients we're deficient in
- Based on food preferences, culture, nutrition knowlege & beleifs, cost, hunger, availability, convenience
- Humans and most animals seek water and food but not the best foods, unless they know how to eat a well-balanced diet
63
When and how much to eat?
- Hunger, satiety and thirst centers located in "primitive" brain (hypothalamus, appetite centre)
- Inborn attration to sweet and salty dislike of bitter and sour
64
"Like" or "dislike"
- Strongest influence is "food preference" (learnered behaviour)
- Shaped by memory and memories are based on culture and pleasure associsated with the memory (food preference)
- Reject foods that bring discomfort, guilt and unpleasant memories
65
Food marketing
| Health Canada says
- Food marketing can influence food choices
- Designed to;
- Create trends
- Encourage you to;
- Buy certain foods or drinks
- Buy foods to get promotional items
- Create links between certain foods or brands and aparticular lifestlye
- Build brand loyalty
66
Colour and food
**Red**: Enhances appetite - increasing heartrate
**Green**: Healthy - eco-friendly, natural
**White**: Reduced calories
**Yellow**: Happiness & youthfulness - brain processes yellow very rapidly
**Orange**: Good value - stimulates appetite & conversation
**Brown**: Rich flavour
**Blue**: Suppress appetite - most unappetizing colour
67
Adequate diets
- Variety of foods provide **sufficient levels** of calories and essentail nutrients
- Adequte diet contains all nutrients necessary for long-term survival may not be optimal or have variety
68
Balanced diets
- Provide calories, nutrients and other compnents in the **right proportions**
- Six classes of nutrients in good proportion
69
Define essential
- Nutrients the body can't produce, or produce in sufficient amounts
- Must be obtained in diet e.g. iron, calcium
70
Define nonessential
Nutrients the body can manufacture in sufficient quantities e.g. cholestrol
71
Recommended nutrient intake
| Higher activity want at higher % range
## Footnote
Lecture 5 pg 4
- Carbohydrates: 45-65%
- Fat: 20-35%
- Protein: 10-35%
- Fiber: (women) 25g-38g (men)
| % of all calories consumed in a day
## Footnote
Fiber based on calorie intake of men and women
72
Over-consumption
| Sugar & fat
Western diet overloaded with:
- Refined sugars (white sugar)
- Saturated fats (animal fats, palm oil)
- Salt
Low in:
- Essential fatty aids
- Dairy products
- Vegetables & fruits
- Fiber
High fat (saturated & trans fats) risk heart disease and metabolic syndrome
Low dairy and vitamin D risk osteoporosis
73
Vegetables and whole grain
6% consumtion of brocoli, cauliflower, brussel spouts & dark leafy greens
- Associated with reduced cancer risk
- Potato most commonly consumed (US)
More whole grains needed
- Reduce risk of certain cancers, type 2 diabetes & heart disease
| Average of 1 serving of whole-grain products daily (US)
74
List food guides
| Healthy Diets
- Canada's Food Guide (HC)
- MyPlate (USDA)
- Mediterranean Food Pyramid (WHO)
75
What was the previous food guide?
1. Grain products
2. Vegetables & fruit
3. Milk products
4. Meat & alternatives
76
What is Canada's food guide?
- Water drink of choice
- 1/2 vegetables & fruits
- 1/4 protein
- 1/4 whole grain
77
What healthy food choices should be made?
1. Eat plenty of vegetables & frutis, whole grains and proteins
2. Choose protein foods that come from plants more often (e..g soy beans, tofu)
3. Limit highly processed foods or less and smaller amounts
4. Water drink of choice
5. Use food labels
6. Be aware of food marketing influencing choice
78
What is the USDA MyPlate?
**Grains**: 1/2 grains whole grains
**Protein**: Vary proteins
**Vegetables**: 1/2 plate fruits & vegetables, vary vegetables
**Fruits**: 1/2 plate frutis & vegetables, focus on whole fruits
**Dairy**: Low-fat or fat-free dairy or yogurt
79
What is the Mediterranean Diet Pyramid?
- 1994 WHO developed to popularize diet associated with reduced heart disease & cancer risk
- Olive oil, breads, whole-grain cereals, nuts, fish, dried, beans, vegetabels & fruits and wine (moderation)
- Red meat intake (monthly) and sweets & poultry (weekly)
- Rich in plant foods, olive oil, limited red meat (**key features**)
| Lecture 5 pg 13
80
Gut
- Approx 92-99% proteins, fats & carbs consumed are digested and absorbed
- Most dietary fibre femented by bacteria
81
Define mechanical digestion
- Physical breakdown
- Chewing, grinding & mixing food with mouth, tongue and teeth
82
Define chemical digestion
- Chemical breakdown using enzymes, bile & hydrochloric acid
- Over 100 enzymes secreted by digestive system
83
What's in the digestive system?
- Mouth
- Pharynx
- Epiglottis
- Esophagus
- Stomach
- Small intestine
- Large intestine
- Rectum
- Anus
## Footnote
Acessory organs:
- Liver
- Gall bladder
- Pancreas
84
What is heartburn?
| Lecture 5 pg 19
- Caused by excessive stomach acid or defective lower esophageal sphincter
- Gastroesophageal disease (GERD) is chronic (severe acid reflux)
- Heartburn is a symptom of acid reflux & GERD
- Stress, anxiety, excessive asprin use (other inflammatory medicines), fatty foods, spicy foods, coffee, alcohol, citrus fruits, soda are involved
- Weight gain & eating within 3 hrs prior to bed increase symptoms
High-fiber diets protect against development
## Footnote
10-20 ibs gain associated with 3-fold increase of heartburn symptoms
85
What are ulcers?
- Damage of protective stomach or duodenum lining
- HCl lowers stomach to 1.5-2 pH
- Stomach acid & digestive enzymes erode lining(s) cause ulcer
- **Duodenal ulcers** 10x more common than stomach ulcers closely associated with Helicobacter pylori (H. pylori) bacteria
- H. pylori infection highest in poor sanitary condition countries
- Classified as Class I carcinogen (causing cancer) - stomach cancer
86
Stomach & SI
- Stomach percolates chyme into SI
- Solid foods stay in stomach (2-4 hrs), liquids pass (20 mins)
- Solid food passes to SI about 1-2 teaspoons at a time
- SI is about 6m long with 3 segments (duodenum, jejunum & ileum)
- Surgace area of SI is about baseball infield (675 ft^2)
- Intestinal cells turn over every 4-5 days (high nutrients needs)
87
Pancreas
| Exocrine
- Pancreatic enzymes breakdown all mayjor energy nutrients
- Carboyhydrates (Amylase)
- Proteins (Protease)
- Fat (Lipase)
- Absorption takes place and small molecules transport into cells lining (SI)
88
Absorption
- End products of digestion are taken by;
- **Blood vessels**: (carbohydrate & protein breakdown products) for distribution
- **Lyphatic vessels**: (fatty acids, fat breakdown)
- Empty into subclavian (feed back to heart)
89
Large Intestine
- Water, sodium & some end products (bacterial digestion) are absorbed
- Bacterica digestion of fiber & complex carbohydrates
- Bacterica excrete gas & short chain fatty acids (absorbed by LI)
- Substances not absorbed are excreted (feces)
90
Constipation & hemorrhoids
- Due to low (too little) fiber diets
- 25 g/day (females) & 38 g/day (male) + plenty of fluids (prevent constipation, fiber passes better)
- Aid in prevention in healthy people
91
Diarrhea
- Dehydration, heart & kidney malfunction and death (severe)
- Mostly due to bacteria or viral-contaminated food or water, lack of immunization against infectious disease & deficiencies of nutrients
- 3.5 million annual child (
92
Bacteria
| Friend or foe
- Discovered bacterica can cause infections (late 1800's)
- Penicillin (1928)
- 90% of children with bacterial meningitis died (before antibiotics)
- Increase antibiotic use increased asthma & obesity (childhood)
93
Gut microbiota
- Can transfer disease
- Breakdown dietary fiber
- Produce vitamins (vitamin K & B)
- Trains immune system (most important)
- Suppress growth of pathogenic bacteria
- Motility & intestinal function
- drug metabolism (>50)
- Affect mood
## Footnote
Most densely colonized ecosystem in human body
94
Dysbiosis
- Imbalanced microbiota causes inflamation
- Causes;
- High fat, high sugar
- Artifical sweeteners
- Dietary emulsifiers (polsobate 80 & carboxymenthylcellulose)
- Ultra-processed foods
## Footnote
Lecture 5 pg 33
95
What is a major modifier of gut microbiome?
- DIET
- Promotes symbiosis (health)
- High fiber
- Whole natural foods
96
Where do calories come from?
- Carbohydrates: **4 kcal/g**
- Protein: **4 kcal/g**
- Alcohol: **7 kcal/g**
- Fat: **9 kcal/g**
97
How do you calculate calorie %?
Lecture 6 pg 5
example pg 6
98
How much energy do we really need?
- 20% PA
- 60-75% (~70%) basal metabolism
- 10% of basal + PA is thermic effect of food
99
What factors impact BMR?
1. Age *(decreases)*
2. Height *(increases)*
3. Growth *(increases)*
4. Body composition* (decreases - less muscle)/(increases - more muscle)*
5. Fever *(increases)*
6. Stress *(increases)*
7. Environmental temperature *(increases)*
8. Fasting/starvation *(decreases)*
9. Malnutrition *(decreases)*
10. Thyroxine *(decreases - hypothyrodism)/(increases - hyperthyrodism)*
100
Adding PA
1. Activity tables ( sum all activity for day)
2. Activity factors (simply multiply by a factor)
Inactive = BM x 1.3
Average = BM x 1.5
Active = BM x 1.75
kcal/min increase with increase body weight - converse is true (PA)
e.g. cycling 15 mph [110 Ib. = 5.4; 200 Ib. = 9.8]
## Footnote
Basal metablism = BM
101
Approximate (very) basal caloric need
Men = body weight (Ibs) x **11** kcal/Ib
Women = body weight (Ibs) x **10** kcal/Ib
e.g. 130Ibs x 10 kcal = 1300 kcal per day
102
Accurate basal caloric need
Men (BMR) = (10 x weight (kg)) + (6.25 x height (cm)) - (5 x age) + 5
Women (BMR) = (10 x weight (kg)) + (6.25 x heigh (cm)) - (5 x age) - 161
103
Total calorie need estimation
**BM**: 130 Ibs x 10 = 1300 kcal
**Add PA**: 1300 x 1.3 = 1690 kcal
**Basal + PA**: 1690 kcal
**Dietary thermogenesis**: 1690 x 0.10 (10%) = 169
**Total**: 1859 kcal
104
Physiological influences for **hunger**
- Empty stomach
- Gastric contractions
- Absence of nutrients
- GI hormones (elevated ghrelin)
- Endorphins (brain's pleasure compounds)
| Ghrelin = hunger hormone
105
Why do we stop eating?
| **Satiation **
- Presence of food triggers stretch receptors
- Nutrients in intestine elicit satiety hormones (GLP-1 & CCK)
106
Why do we not start eating yet?
| **Satiety**
- Nutrients in blood signal brain
- As nutrients diminish, satiety dimished & hunger develops
- Hunger hormones increase (ghrelin)
107
Stages following hunger
1. **Hunger**
2. Seek food
3. Continue meal
4. **Satiation**
5. Meal ends
6. **Satiety**
108
Body composition importance
- **Fat, muscle, bone & organs**
- **Essential fat**: men 3%; women 12% (bone marrow, CNS, internal organs)
- **Acceptable % body fat**:
*Men* 18-25% (>/equal 26% obese)
*Women* 25-31% (>/equal 32% obese)
- **Fitness % body fat**:
*Men* 14-17%
*Women* 21-24%
Below certain threshold experience: **infertility, develop depression, abnormal hunger regulation, unable to keep warm**
109
Body compostition
- Excess fat chest & stomach areas (apple-shaped; visceral/central abdominal fat)
- Higher risk of diabetes, heart disease & hypertension
- Excess fat hips, thighs & butt (pear-shaped; subcutaneous fat) (lower risk)
- Risk when waist;
Male > 102 cm
Female > 88cm
110
Metabolic syndrome
Presence of 3:
- Abdominal obesity
Men: waist circumference > 102 cm (40 inches)
Women: waist circumference > 88 cm (35 inches)
- Elevated triglyceride levels (blood)
- Low HDL levels
- High blood pressure/hypertension
- Impaired fasting glucose
111
List the measurements of body composition
1. Fat-fold
2. Underwater weighing
3. Bioelectrical impedance
4. DXA
112
Fat-fold
Caliper gauges thickness of skin fold (tricep, subscapular, chest, abdomen or thigh)
113
Underwater weighing
- Measure body density weighing perdon on land then submerged in water
- Uses amount of water displaced & known density of fat mass & lean mass
- Volume of fat weighs less than muscle & muscle has a constant mass displaying a specific amount of water
114
Bioelectrical impendance
- Low-intensity electrical current
- Lean tissue conducts more current, fat is more resistant to current
115
DXA
Low-dose x-ray absorption to measure lean & fat mass and bone density
116
Fat deposition
Lecture 6 pg 27
117
Weight loss
| Dieting
- Greatest weight loss (1st week)
- Loss of CHO & H2O (70% H2O, 25% fat, 5% lean mass)
- Mainly lose glycogen (1g glycogen: 3g H2O)
- Rapid weight regain resume normal eating after 1 wk
2nd week
- 20% H2O
- Fat and lean mass
3rd week
- H2O loss (minimal)
- Fat & lean mass
Fewer kcal to maintain lower body weight makes weight loss harder (basal energy needs tied to weight - proportional)
118
Fat cell development
| Lecture 6 pg 28
1. Hyperplasia (new cells)
2. Hypertrophy (bigger)
3. Hyperplasia (new cells)
- Occurs at critical periods late childhood (adiposity rebound); puberty; cells reach max size
Adipose cell # increases
119
Fat storage
LPL (lipoprotein lipase): promotes fat storage (adipose & muslce)
High LPL store fat very efficiently
Obese individuals have more LPL activity per fat cell and more fat cells
Modest excess energy intake has more dramatic effect (obesity vs lean)
120
LPL
Gender-specific hormones:
- Women fat cells in breasts, hips & thighs (estrogen) more LPL
- Men cells in abdomen more LPL
After weight loss LPL increases, reason for easy weight gain & loss
Set point; increase is more dramatic in obese individuals
## Footnote
5% of diets are successful
121
Leptin increase
- Negative energy balance (lose weight)
- High levels (blood) hypothalamus produces proteins (melanocortins) that dampen appetite
122
Leptin decrease
- Positive energy balance (gain weight)
- low levels (blood) hypothalamus produces protein (neuropeptide Y) stimulates appetite slows energy expenditure
123
Medication
| Canada
- Contrave (naltrexone & bupropion) combination
- Low does naltrexone (manage aclcohol & opioid dependency) & bupropion (antidepressan & smoking cessation)
- Act on 2 seperate areas of the brain controlling hunger & cravings
- Oral intake
124
Saxenda
- GLP-1 satiety hormone (naturally present in the body)
- Decreases appetite
- Prefilled pen (self-injection)
125
Xenical
- Blockes fat absorption (intestine) take fewer calories
- Capsule taken during or just following main meal
126
Why are diets unsuccessful?
- Often hard to follow
- Often different from what we know
- Easy to slip off diet or cheat
- Want a qick fix that works
- Persistent obesity changes biology of the body
## Footnote
3500 kcal estimated = 1ibs (myth)
127
New biology
## Footnote
Hinder weight loss/maintenance
Full year after significant weight loss
- Grelin 20% higher
- PYY 20% lower
- Body acted as if starving
- "Post-dieting syndrome"
Post weight loss
- Muslce biopsy burns 20-25% less energy (low-intensity & everyday activities)
- Skeletal muslce working more efficiently
Following calorie restriction
- Caloric deprivation increases the reward value of high calorie-foods more than low calorie
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Drastic Measures
- Prolonged fasting
- Bariatric surgery
- Liposuction
Each one carries risks & latter are expensive
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Prolonged fasting
Causes intestional starvation
- 50-80% intestinal nutrients are provided by food
- Balance is provided by the bloodsrteam
Mucus & cells are lose from GI tract linings
Differs from intermittent (results in similar degree of weight loss & improvement insulin sensitivity)
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Bariatric surgery
Only available to certain clinical population
- Over 18
- BMI > 40 kg/m^2
- BMI > 35 kg/m^2 plus 1 or more (high cholesterol, high blood pressure, sleep apnea, diabetes or joint issues)
Reduce weigh by about 50% & most maintain weight loss
Complication risks during and after
Very expensive
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Gastric band
- Safest baraiatric surgery
- Requires routine follow up for band adjustments
- 40% loss of excess bosy weight over 24+ months
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Gastric bypass
- Reduce stomach size from small football to an egg
- Bypass first section of SI
- 60-85% loss of excess body weight within 12-18 months
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Sleeve gastrectomy
- About 2/3 stomach removed, leaving a sleeve/ tube behind
- Hunger cells removed giving metabolic response
- 50-80% loss of excess body weight in 12 months
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Liposuction
Max amount of fat removed 5L (4.5 kg)
Cosmetic (not intended for weight loss)
Risks;
- Skin appear bumpy, wavy or withered (uneven fat removal)
- Changes may be permanent
Permanently remove fat cells from targeted areas
Fat still stored in different parts of the body if gain weight
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Characteristics of maintainers
- Regularly exercise
- Small & comfortable changes in diet & physical activity
- Eat breakfast
- Choose low-fat foods
- Keep track of weight, dietary intake & physical activity level
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Characteristics of weight regainers
- Little exercise
- Use popular/fad diets
- Make drastic & unpleasant changes in their diets & physical activity levels
- Take diet supplements
- Cope with problems & stress by eating
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National weight loss registy?
- Established in 1994 to try to identify behaviours associated with long term weight loss success
- Largest observational study of weight maintenance
- Includes individuals who have maintained weight loss of at least 30Ibs (at least 1 year)
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Winning patterns of NWCR members
- 98% modify food intake in some permanent way (portion control, low fat diet)
- 90% exercise at least 1 hr/day buring at least 400 calories per session
- 78% eat breaktfast each day
- 75% weigh themselves once a week
- 62% watch less than 10hrs of TV per week
- Average daily calorie intake (women) 1306 kcal
- Average daily calorie intake (men) 1685 kcal
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Liquid calories vs. solid food calories
- Liquids count as calories the body doesn't detect them the same way as solid food (Scientific evidence)
- Calories from solids naturally compensate by reducing rest of food intake
- Ingestion of liquid calories (alcohol, juice or soda) dont compensate for by eating less calories
- Mechanisms controlling hunger & thirst are compeletly different
- Liquids (containing calories) don't satisfy hunger ever if thirsty
- Fluid calories don't hold satiety properties
- Calories in liquid don't suppress ghrelin as effectively as food caloried (even same # of calories) - David Cummings
- Soup & smoothies are very satiating
