KNES 237 Midterm 1 Flashcards
What is nutrition
A n interdisciplinary science that studies food and health with a focus on the nutrient and chemical properties of foods.
How long can you survive without food or water
- 2 weeks without food and 3 days without water, but depends on amount of fat stored and muscle in the body
Food security:
Access at all times to sufficient supply of safe, nutritious foods (don’t have to scavenge or steal food)
Food insecurity:
Limited or uncertain availability of safe, nutritious foods- or ability to acquire them in socially acceptable ways.
Food insecurity can lead to…
- Can lead to poor quality diet
- greater risk of chronic disease
- maybe due to: poverty, absence of supermarkets, access to inexpensive, high calorie (low nutrition) foods, limited cooking facilities
Food insecurity percents:
36.7% in nunavet
8.0% in alberta
8.1% in Canada
14.3% in USA
What are calories?
A unit of measure that represents of the amount of energy supplied by food, kilocalorie (kcal, C)
Nutrients:
- Chemical substances used by the body
- Help sustain growth and development
What are the 6 categories of nutrients?
- Carbohydrates (CHO) Energy nutrient
- Protein- Energy nutrient
- Fat- Energy nutrient
- Vitamins
- Minerals
- Water
Vitamin A inadequate intake:
- Reduced liver stores, blood levels
- impaired ability to see in dim light
- Long term: lead to loss of vision
Vitamin A high intake:
- Hypervitaminosis A (500,000 IU or 50,000 IU long term
- Nausea, irritability, blurred vision, headache
- liver damage
- birth defects
Estimated average requirement (EAR)
The average daily intake level estimated to meet the needs of half the people in a certain group. Scientists use it to calculate the RDA.
Recommended dietary allowance (RDA)
The average daily intake level estimated to meet the needs of nearly all people in a certain group. Aim for this amount!
Adequate intake (AI)
the average daily intake level assumed to be adequate. It is used when an EAR cannot be determined. Aim for this amount if there is no RDA!
Tolerable upper intake level (UL)
The highest average daily intake level like to pose no health risk. Do not exceed this amount on a daily basis!
Malnutrition…
can result from poor diets, disease, genetic factors, or a combination of these factors
3 nutritional deficiencies:
- Under consumption= developing nations (famine)
- Over consumption= typical western diet (contributes to obesity)
- Under nutrition= from refined foods, lack of micronutrients
Some groups of people are at higher risk of becoming malnourished than others…
Infants, pregnant women, elderly, ill or recovering from illness
Bad nutrition…
can influence the development of certain chronic diseases
Key points
- adequacy, variety, and balance are key point of a healthful diet
- There are no “good” or “bad” foods
What is Orthorexia Nervosa
- Unhealthy fixation with eating healthy
- can lead to nutritional deficits
No specific category in DSM (Diagnostic and statistical manual) but falls under avoidant/restrictive food intake disorder (ARFID)
Strawpoll, percent of deaths In the world/Canada
- heart disease 33%
- cancer 18%
- Pneumonia 4.4%
- neurological diseases 3.9%
- Diabetes 2.7%
- HIV/AIDS 1.5%
Risk factors: a condition or behaviour associated with an increased frequency of a disease but not proved to be casual
Dietary, genetics, age, sedentary lifestyle, smoking and tobacco use, stress, environmental containments
Mortality rate attributable to diet and # of deaths at the global level attributable to diet
Diet high in sodium
diet low in whole grains
diet in low in fruits
Western diets…
- promote chronic diseases
- diets high in salt, refined grains (white flour)
- diets in processed meats, refined sugars (white sugar)
- diets low in fruits, vegetables and fiber
Unhealthy weight in adults
36.3% have overweight + 26.8% have obesity= 63.1% unhealthy weight
- greatest recent increase in obesity is in 20 to 39 year olds
Unhealthy weight in children
17% have overweight + 9% have obesity= 26% unhealthy weight
- obesity is a complex, multifactorial chronic disease. Calorie intake is just one contributor
Are ancient diets best?
- Some claim the healthiest diet is one that was eaten during the palaeolithic era 10000 years ago
- the paleo diet restricts what you eat to foods the hunter-gathers of the Stone Age ate
- They would overeat when food was available to protect them during famine
- Very common to cycle through period of feasting or famine
- “Feast or famine”
Diets have changed but the body has not..
- There are biological processes in the body that make it difficult to stay healthy in the current food environment
- We get hungry every 4-6 hours even in the presence of excess body fat stores, today this can lead to consuming more calories than we burn
- Our bodies conserve sodium – historically, diets were low in sodium and there was lots of vigorous activity, sweating, and diarrhea – so it was advantageous to conserve sodium for survival.
– Today, this conservation of sodium in the context of a high sodium (salt) diet, leads to high blood pressure.
Sweet taste and bitter taste…
We naturally prefer fatty and sweet-tasting foods:
– sweet taste – we evolved to associate sweet taste with calories and
nutrients that are safe for human consumption; help orient our
behavior to seek out and consume these foods
– bitter – associated with toxic products (a lot of good vegetables taste
bitter therefore people consume fewer)
– Today, we overconsume sugary foods and eat fewer vegetables.
were they healthier during the Stone Age?
- Many died of starvation
- vitamin deficiencies and food poisoning
- died younger so less degenerative diseases
Should we eat like they did?
Not necessarily..
- meat differs (leaner back then)
- fruits and vegetables differ ( different types, nutrient levels may vary)
- Environment is different (more pollution, sedentary behaviour)
- Strive for more exercise and wholesome foods
Nutrition in the media… typical problems
- tight deadlines
- limited understanding
- single study
- report scientific findings prematurely
half- truths and hype are common in books, newspapers, magazines, tv, radio, pamphlets, internet, speeches, etc.- but we have the right to free speech…
Laws about nutrition in media..
- It is unlawful to state false claims on a product label or in an advertisement
- it is unlawful to use the U.S. or Canadian mail systems to send fraudulent products or receive payments for fraudulent products
- BUT RARELY ARE THESE LAWS ENFORCE, AND PENALTIES ARE MINIMAL
What is the primary reason for nutrition misinformation?
- Profit
- As long as people think there is a quick and easy way to lose weight, build muscle, slow aging and reduce stress, there will be a huge market for “nutritional” products and services
- The world market for vitamins alone is over 3 billion dollars.
Identifying Nutrition experts: Register dietitian
- B.Sc. in nutrition
- Internship
- National licensing exam
- Registration (College of Dietitians of Alberta)
- RD
Identifying nutrition experts: Nutritionist
- Before September 2016 the title ‘Nutritionist’ could be used by anyone in Alberta to describe themselves as a professional in the Nutrition industry.
- As of September 2016, the title ‘Nutritionist’ can only be used by members of the College of Dietitians of Alberta.
– Registered Dietitian - Registered Nutritionist
– RD - Dietitian
– Nutritionist *
What are sources of reliable nutrition information?
- Health organizations (eg. Heart and Stroke Foundation; Canadian Diabetes Association)
- Scientific organizations (eg. Canadian Nutrition Society)
- Professional organizations (eg. Dietitians of Canada)
- Government publications (eg. Health Canada)
- Registered, licensed or certified dietitians
- Nutrition textbooks (not diet best sellers)
Importance of research
Facts and evidence provided by scientific studies: used to develop nutrition information and guidelines that affect publics health.
- peer-reviewed paper published in scientific journals
Identifying nutrition Quakery
- too good to be true or a quick fix
- Testimonials (before and after pictures)
- Make you suspicious of food supply
- Fake credentials
- elimination of whole food groups
- Use of the word ‘natural’
- supplements needed by all; megadoses
What foods must be labeled?
- Foods containing more than one ingredient (mostly processed foods)
- Dietary supplements
- If a claim is made- “low fat,” “low calorie,” etc.
- must display nutrition information backing the claim but beware:
-Light: no guideliens - Low sugar: no guidelines
- Reduced fat or calories: 25% less than the original
- Fat free: <0.5g
Foods that are not required to be labeled
- fresh fruits and vegetables
- raw, single-ingredient meat, poultry, fish and seafood
seafood - very small packages, such as one-bite candy
- items with insignificant calories and nutrients, such as
herbs and spices - food sold at farmer’s markets
- food sold only in grocery stores where the product is
prepared or packaged in-store (e.g. bakery, salads) - alcoholic beverages: water, tea or coffee without anything added to it
New nutrition labels in Canada…
- Calories is larger and stands out more with bold line below
- Serving size stands out more
- Daily values updated
- New % daily value for total sugars
- mg amounts are shown
- Updated list of minerals of public health concern
Organic food labels
Financial penalties can be imposed on companies that use the label inappropriately.
Should be lower in hormones, antibiotics, and pesticide and herbicide residues.
Only products with organic content of can be labelled as organic.
greater than or equal to 95%
‘Organically grown’, ‘organically raised’ or ‘organically produced’ all mean the same as organic and meet the same requirements.
True
If a multi-ingredient product has 70 to <95% organic content
- Must declare the percentage of organic
content on the label - May NOT use the organic logo nor the claim
organic - If <70% organic content, can only indicate
which ingredients are organic in the
ingredient list
Is organic food always healthier than non-organic?
Nutrient-wise (protein/vitamins/etc.) they are similar. One difference is that organic fruits & vegetables can have higher antioxidant content. Organic diets do lead to less pesticide exposure.
- Avocados, cantaloupe, pineapple, broccoli, cabbage and corn have low levels of pesticides, so less advantage to buyingorganic.
- Strawberries, spinach, grapes, apples, tomatoes and celery have higher levels of pesticide residues.
Given the cost of organic foods, it may not be feasible for many Canadians — we should encourage Canadians to eat more fruits & vegetables – closing that gap would be
equally or more important for health.
Enriched or fortified
- Vitamin and mineral content of food is increased by enrichment and fortification
- Definitions established more than 50 years ago
Enrichment:
- Pertains only to refined grin products where thiamin, riboflavin, niacin, and iron lost in milling are added
- Producers of bread, cornmeal, pasta and crackers from refined grains must use enriched flours
- Example: robin hood flour
Fortification:
- Is the addition of a vitamin or mineral nor normally found in the food
- Example: simply orange juice
The ingredient label
- All ingredients must be listed in descending order of amount present (by weight)
- Ingredients causing allergic reactions (peanuts, tree nuts, milk, eggs, fish, shellfish, wheat, soy, sesame and sulphites) must also be listed on the ingredient label
food additives on the label
- Food additives must be listed
- 3000 chemicals are added to food to enhance its flavor, color,
texture, cooking properties, shelf life, or nutrient content - Food additives with “GRAS” can be used without pre-approval
(Generally Recognized As Safe)
– Sodium chloride, sucrose, cornstarch, many vitamins/minerals - New additives must be approved by Health Canada prior to use
Irradiated foods
- must contain radar symbol
- Uses: prevent sprouting, delay ripening, kill insects/mold/bacteria, potatoes, onions, wheat, flour, spices, ground beef
- Foods do not retain radioactive particles
- Doses: 10-20x higher than lethal dose in humans
Dietary supplement labeling
- Dietary supplements must be labeled
- Dietary supplement labels cannot claim the products treat, cure, or prevent disease
- Not classified as a drug, so no vigorous testing
We are not born knowing what to eat…
- Don’t generally seek nutrients we are deficient in
- Select food based on preference, culture, nutrition knowledge and beliefs, cost, hunger, availability, convenience
- Humans and most animals will seek water and food, but not generally the best foods, unless they have learned how to eat a well-balanced diet
How do we decide when and how much to eat?
- Hunger, satiety(feeling full or satisfied) and thirst centres are located in the “primitive” brain: Hypothalamus- appetite centre
- Inborn attraction to sweet and salty tasting foods, dislike of bitter and sour foods
What do infants prefer?
Infants like sweets, more than sour or bitterness
What makes us like or dislike?
- The strongest influence is “food preference,” a learned behaviour
- Food preference is shaped by memory and memories are based on culture and the pleasure associated with memory
- we reject foods that bring us discomfort, guilt and unpleasant memories (e.g. eating something that gave us food poisoning; as a child having to eat vegetables before leaving the table.
Food marketing:
Can influence food choices it is designed to:
- create food trends
- encourage you to:
buy certain foods or drinks
buy foods in order to get promotional items such as loyalty points, tickets to movies or sports events, coupons for future food purchases
- create links between certain foods or brands and a particular lifestyle
- build brand loyalty so you will continue to purchase from a particular store or products with a brand name
Red food colour
enhances appetite; increases heart rate
Green food colour
healthy; eco-friendly; natural
white food colour
reduced calories
Yellow food colour
happiness and youthfulness; brain processes yellow very rapidly
Orange food colour
good value; stimulates appetite and conversation
Brown food colour
rich flavour
Blue food colour
suppress appetite; most unappetizing color
Adequate diets
- Variety of foods provide sufficient levels of calories and essential nutrients
- an adequate diet contains all nutrients necessary for long-term survival but it may not necessarily be optimal or have any variety.
Balanced diets
- provide calories, nutrients, and other components in the right proportions
- A balanced diet has the six classes of nutrients in good proportion
Essential nutrients
Nutrients the body cannot produce, or produce in sufficient amounts; must be obtained in the diet. example: iron, calcium
Nonessential nutrients
Nutrients the body can manufacture in sufficient quantities. Example: cholesterol
Recommended amount: Carbohydrates
45-65%
Recommended amount: Fat
20-35%
Recommended amount: Protein
10-35%
Recommended amount: Fiber
25g for women
38g for men
Western diet overloaded with…
Refined sugars
saturated fats
salt
High intakes of fat (saturated fat and trans fat) are risks for heart disease and metabolic syndrome
Western diet low in…
Essential fatty acids
dairy products
vegetables and fruits
fiber
Low intake of dairy products and vitamin D are risks for osteoporosis
Vegetables:
Only 6% of adults regularly consume broccoli, cauliflower, Brussels sprouts, or dark, leafy green vegetables
– These are associated with reduced cancer risk
– Most commonly consumed vegetable in the U.S. is the potato
Whole grains:
More whole grains are needed
– Whole grains reduce the risk of certain types of cancer, type 2 diabetes and heart disease
* Americans consume an average of one serving of whole-grain
products daily
Old food guide
Focused on 4 food groups:
1. grain products
2. vegetables and fruit
3. milk products
4. meat and alternatives
New food guide
focuses on broader statements and no longer uses the food group categories
USDA MyPlate
Grains: Make half your grains whole grains.
Protein: Vary your proteins.
Vegetables: Make half your plate fruits and vegetables; vary your vegetables.
Fruits: Make half your plate fruits and vegetables; focus on whole fruits.
Dairy: Move to low-fat or fat-free dairy milk or yogurt.
Mediterranean diet pyramid
- WHO developed guide in 1994 to help popularize a diet associated with reduced risk of heart disease and cancer
- Emphasizes olive oil, breads, whole-grain cereals,
nuts, fish, dried beans, vegetables, and fruits; and wine in moderation - Intake of red meats is limited to monthly, and sweets
and poultry to weekly intake - Key features: rich in plant foods, olive oil, limited red meat
The Gut
- Approx. 92-99% of the protein, fat and carbohydrate that we consume is digested and absorbed
- Most of the dietary fiber is not digested, most is fermented by bacteria
Mechanical digestion
- Physical breakdown of food
- chewing, grinding and mixing food with mouth, tongue and teeth
Chemical digestion
- Chemical breakdown of food using enzymes, bile and hydrochloric acid
- There are over 100 enzymes that are secreted by the digestive system
Digestive system is made up of:
Mouth
Pharynx
epiglottis
esophagus
stomach
small intestine
large intestine
rectum
anus
Accessory organs in digestive system
Liver
gall bladder
pancreas
Heartburn notes 1
- Caused by excessive stomach acid or defective lower esophageal sphincter – causes burning sensation in the esophagus.
- Acid reflux is a common medical condition that can range in severity from mild to serious. Gastroesophageal reflux disease
(GERD) is the chronic, more severe form of acid reflux. Heartburn is a symptom of acid reflux and GERD. - Stress, anxiety, frequent use of aspirin and other anti-inflammatory medicines, fatty foods, spicy foods, coffee, alcohol, citrus fruits, soft drinks, and other foods are involved.
- Weight gain and eating within 3 hours prior to going to bed increase symptoms
– weight gain of 10-20 pounds associated with a 3-fold increase in heartburn symptoms
Heartburn treatment
- High-fiber diets protect against development of heartburn
- Treatments include: stress reduction, elimination of offending foods, eating small and frequent meals
– mild occasional heartburn can use over-the-counter antacids but with persistent symptoms, prescription medication may be needed (e.g. H2 blockers, proton pump inhibitor)
Ulcers:
- Develop when protective stomach or duodenum lining is damaged
- HCl lowers the ph of the stomach to about 1.5-2
- Stomach acid and digestive enzymes erode the lining(s) and cause an “ulcer”
Duodenal ulcers
- 10x more common than stomach ulcers and are closely associated with helicobacter pylori (H. pylori) bacteria conditions
- Classified as class 1 carcinogen-stomach cancer
Class 1 Carcinogens
- Known human carcinogens:
– Alcoholic beverage consumption
– Asbestos
– Cadmium
– Engine exhaust, diesel
– Epstein-Barr virus (infection with)
– Human papilloma virus (HPV)
– Ionizing radiation: CT scans, continuous
– Workplace exposure as a painter
– Tobacco smoke, secondhand, smokeless
– Radon: leading cause of lung cancer
Stomach to small intestine
- Stomach percolates chyme into the small intestine
– Solid foods stay in stomach for about 2-4 hours, liquids pass through in
about 20 minutes
– Solid food is passed to the small intestine about 1 to 2 teaspoons at a time - The small intestine is about 6 meters long and composed of 3 segments: duodenum, jejunum, and ileum
- Available surface area of small intestine is about the size of a baseball infield, 675 square feet
- Intestinal cells turn over every 4-5 days
– High nutrients needs
The exocrine pancreas
- The enzymes produced by the pancreas act to breakdown all of the major energy nutrients: Carbohydrates (Amylases), Proteins (Proteases), Fat (Lipases)
- Absorption also begins to take place. Small molecules are transported into cells lining the small intestine.
Absorption: Blood vessels
Carbohydrate and protein breakdown products, for distribution to the body
Absorption: Lymphatic vessels
Fatty acids from fat breakdown, empty into the subclavian veins that feed back to the heart
The liver
Many functions:
* Detoxification ( amino acid catabolism yields ammonia – neurotoxin - liver converts ammonia to urea)
* Protein synthesis (clotting factors, IGF-1)
* Metabolic control (glucose, lipids)
* Glycogen formation and storage
* Triglyceride and cholesterol production
* Produces bile (stores in gallbladder)
* Red blood cell degradation
* Hormone production
* Amino acid synthesis
* Stores vitamin A, D, B12, iron & copper
* Synthesizes angiotensinogen
The large intestine:
- Water, sodium, and some of the end products of bacterial digestion are absorbed from the large intestine
- Bacteria digest fiber and complex carbohydrates that we can’t digest
- These bacteria excrete gas and short chain fatty acids that can be absorbed in large intestine
- Substances that cannot be absorbed are excreted as feces
Constipation and hemorrhoids
-Are due to diets with too little fiber
- Adults need fiber intakes of 25g/day (females) to 38g day (males) plus plenty of fluids
- this regiment will help prevent constipation and hemorrhoids in healthy people
Diarrhea
- Severe diarrhea leads to dehydration, heart and kidney malfunction, and death
- Most due to bacterial - or viral contaminated food or water, lack of immunizations against infectious diseases, and deficiencies of various nutrients
- 3.5 million deaths from diarrhea occur annually to children five years old or less
Bacteria discovery:
- Late 1800’s discovered bacteria can cause infections
- 1928 penicillin was discovered
- Before antibiotics, 90% of children with bacterial meningitis died
- higher antibiotic use coincided with higher childhood asthma and obesity
Microbiota gut
The most densely colonized ecosystem of the human body
Human Gut microbiota in health
- Break down dietary fiber
- Produce certain vitamins (vitamin K, B vitamins)
- Trains the immune system
- Suppress growth of pathogenic bacteria
- Motility and intestinal function
- Drug metabolism (>50)
- Affect mood
- 40 trillion microbes
- Very important for enfants, the gut trained the immune system
Diet is a major modifier of the gut microbiome
Promote symbiosis-health
- high fiber
- whole natural foods
Dysbiosis- imbalanced microbiota
High fat, high sugar
Artificial sweeteners
Dietary emulsifiers
ultra-processed foods
Calorie are a unit of measure
- A dietary calorie is one kilocalorie (kcal)
- the amount of heat required to raise the temperature of 1kg of water 1 degree Celsius
Calories from carbohydrates and protein
4 kcal/gram
Calories from alcohol
7kcal/gram
Calories from fat
9 kcal/gram
calculate % calories
A food item has 15 g carbohydrate, 10 g protein and 5 g fat and a total of
145 total calories. How many percent of calories are contributed by each
nutrient?
15 g Carbohydrate x 4 kcal/g= 60 kcal
10 g Protein x 4 kcal/g = 40 kcal
5 g Fat x 9 kcal/g = 45 kcal
Total: 145 kcal
Carbohydrate: 60 kcal/145 kcal = 0.41 X 100 = 41%
Protein: 40 kcal/145 kcal = 0.28 X 100 = 28%
Fat: 45 kcal/145 kcal = 0.31 X 100 = 31%
100%
How much energy do we really need?
20% physical activities
10% of basal + physical activity, thermic effect of food
90-75% basal metabolism
Basal metabolic rate (BMR)
The rate at which the body uses energy during rest to keep vital functions going, such as breathing and keeping warm
Factors to BMR
- Age- higher age then the basal rate drops
- Height- the taller the bigger the BMR
- Growth- during growth higher
- Body composition- More muscle, higher BMR, but more fat means lower BMR
- Fever- higher BMR
- Stress- higher BMR
- Environmental temperature- higher BMR temporally
- Fasting/starvation- decrease BMR
- Malnutrition- Decrease BMR
- Thyroxine- increase BMR when hyper, decrease when hypo
(very) approximate basal caloric need
Men = Body weight (lbs) x 11 kcal/lb
Women = Body weight (lbs) x 10 kcal/lb
(e.g. 130 lbs x 10 kcal = 1300 kcal per day)
adding PA to basal caloric need
Physical activity:
* kcal/min with body weight – converse is true
e.g. cycling 15 mph [110 lb. = 5.4; 200 lb. = 9.8]
1. Activity tables (sum all activity for the day)
2. Activity factors (simply multiply by a factor)
Inactive = basal metabolism x 1.3
Average = basal metabolism x 1.5
Active = basal metabolism x 1.75
Physiological influences for hunger
Empty stomach
Gastic contractions
Absence of nutrients
GI hormones (elevated gherkin)
Endorphins (brain’s pleasure compounds)
Why do we stop eating?
Presence of food triggers stretch receptors
Nutrients in intestine elicit satiety hormones: GLP-1 or CCK
Why do we not start eating yet?
Nutrients in blood signal brain.
As nutrients diminish, satiety diminishes and hunger develops.
Hunger hormones increase- Gherlin
Importance of body composition
- Fat, muscle, bone & organs
- Essential fat: men 3%; women 12%
(bone marrow, central nervous system, internal organs) - Acceptable % body fat: men 18-25% (≥26% classified as obesity) women 25-31% (≥32% classified as obesity)
- Fitness % body fat: men 14-17% women 21-24%
- Below certain threshold may experience: infertility, develop depression, abnormal hunger regulation, unable to keep warm
Body composition
- excess fat in chest and stomach= higher risk for diabetes, heart disease, and hypertension than excess fat in the hips, thighs, and buttocks.
- At risk when waist is:
88cm< for women
102cm< for men
Metabolic syndrome:
- Abdominal obesity
– Waist circumference greater than 102 cm (40 inches) for men,
– Greater than 88 cm (35 inches) for women. - Elevated levels of triglycerides (1.7 mmol/L).
- Low levels of HDL (<1.0 mmol/L for men & 1.2 mmol/L for women)
- High blood pressure/hypertension (> 130/85)
- Impaired fasting glucose (> 6.1 mmol/L)
Fat-fold measures:
- Use caliper to gauge thickness of a fold of skin on back of arm (tricep), below shoulder blade (sub scapular), chest, abdomen, thigh
Underwater weighing:
- measure body density by weighing person first on land and then submerged in water. Uses the amount of water displaced and
the known density of fat mass and lean mass. By volume, fat weighs less than muscle, and kg for kg, fat, and muscle each have a constant mass and displace a specific amount of water.
Bioelectrical impedance:
use low-intensity electrical current. lean tissues conduct more current, fat more resistant to current
DXA:
use low-dose x-ray absorption to measure lean and fat mass and bone density
Limitation of BMI:
Two men have the same BMI but when is build and other is obsessed, different health risks
Weight loss by dieting
- Greatest weight loss is during the 1st week of dieting…
– It is a loss of CHO and H 2 O (70% H 2 O, 25% fat, 5% lean mass)
– We lose primarily glycogen: 1 gram glycogen: 3 g H 2 O
– Rapid weight regain when you resume normal eating after 1 wk - Weight loss becomes increasingly difficult because you need fewer kcal to maintain new lower body weight (basal energy needs are tied to body weight – and they go down
as body weight goes down)!
2nd week dieting
- 20% water
- fat and lean mass
3rd week dieting
- Minimal water loss
- fat and lean mass
A critical enzyme affecting fat storage
- LPL(lipoprotein lipase): promotes fat storage in adipose and muscle
- people with high LPL store fat very efficiently
- individuals with obesity have more LPL activity per fat cell and more fat cells - even modest excess in energy intake has more dramatic effect in an individual with obesity versus lean.
LPL role in body fat storage
- gender-specific hormones: in women fat cells in breasts, hips & thighs produce more LPL and in men cells in abdomen produce more LPL
- after weight loss - LPL increases – explains why you lose weight and regain so easily – set point; the increase is more dramatic in individuals with obesity
Increase in leptin
Negative energy balance
Decrease in leptin
positive energy balance
How do we gain adipose tissue
Lowering your temperature
adding iron into your diet
Contrave( naltrexone and bupropion)
– low dose naltrexone (medication used to manage alcohol and opioid dependency) plus bupropion (antidepressant that’s also prescribed for smoking cessation)
– work on two separate areas of the brain that control hunger and cravings
– oral tablet
Saxenda (liraglutide)
– GLP-1 (glucagon-like peptide-1) is a satiety
hormone found naturally in your body. Acts
by decreasing appetite
– pre-filled pen that you self-inject
Xenical (orlistat)
– Blocks fat absorption in the intestine,
therefore you take in fewer calories
– capsule taken during or just following each
main meal
Why are diets so unsuccessful?
- They are often hard to follow
- They are often very different from what we
are accustomed to - It’s easy to slip off the diet and “cheat”
- People want a quick fix that works
- Persistent obesity changes the biology of the body
- 3500 ~ 1 pound – a myth? YES!!!
Full year after significant weight loss
- Gherlin- 20% higher
- PYY- 20% lower
- body acted as if starving
- “post-dieting syndrome”
Post weight loss
- Muscle biopsy: burns 20-25% less energy during low-intensity exercise and activities of daily living
- skeletal muscle work efficiency increased
Following calorie restriction
- Functional Mri- activation in the attention and reward regions in response to food
- Caloric deprivation increases the reward value of high-calorie foods more than low calorie foods
Drastic measures during diet
-Prolonged fasting
-bariatric surgery
-Liposuction
-Each of these carries risks and the latter are expensive
Prolonged fasting
- Causes “intestinal starvation”
– 50 - 80% of intestinal nutrients are provided by the food we eat
– The balance is provided by the bloodstream - Mucus and cells are lost from the GI tract linings
- Different from intermittent fasting – latest trend
– “In clinical trials, caloric restriction and intermittent fasting result in similar degrees of weight loss and improvement in
insulin sensitivity.” Curr Obes Rep 2018 7:172-185
Surgery to loose weight
- Only available to a certain clinical population
- over 18 years old
- BMI > 40 kg/m²
- BMI > 35kg/m² plus 1 or more of high cholesterol, high blood pressure,
sleep apnea, diabetes, or joint problems - have tried different ways to manage weight but it remains high
- Can reduce weight by ~50% and most can maintain the weight loss
- Risks of complications during and after surgery
- Very expensive
Gastric band
- Safest type of bariatric surgery, but requires routine follow up for band adjustments.
- 40% of excess body weight over 24+ months
Gastric bypass
- reduce stomach from size of small football to an egg; bypass first section of small intestine
-60-85% of excess body weight within 12-18 months
Sleeve gastrectomy
- about 2/3 of stomach removed, leaving a sleeve/tube behind. Hunger cells are removed giving a metabolic response
- 50-80% of excess body weight within 12 months
Liposuction
- Maximum amount of fat removed is 5 litres (about 4.5 kg)
- Cosmetic surgery; not intended for weight loss
- Risks including that your skin may appear bumpy, wavy or withered due to uneven fat removal, poor skin elasticity and unusual healing. These changes may be permanent.
- Liposuction permanently removes fat cells from the targeted areas of the body. So, if you gain weight, the fat will still be
stored in different parts of the body.
Maintain weight loss
Those who maintain their weight loss:
* Exercise regularly.
* Make small and comfortable changes in diet and physical activity.
* Eat breakfast.
* Choose low-fat foods.
* Keep track of their weight, dietary intake, and physical activity level.
Regain weight back
Those who regain weight:
* Exercise little
* Use popular/fad diets
* Make drastic and unpleasant changes in their diets and
physical activity levels
* Take diet supplements
* Cope with problems and stress by eating
National weight loss registry history
- Established in 1994 to try to identify behaviors associated with long term
weight loss success. - Largest observational study of weight maintenance and includes
individuals who have maintained a weight loss of at least 30 lbs for at least
1 year.
Winning patterns of national weight loss registry members:
- 98% modify their food intake in some permanent way: portion control, low
fat diet - 90% exercise at least 1 hour per day, burning at least 400 calories per
session - 78% eat breakfast every day
- 75% weigh themselves once a week
- 62% watch less than 10 hours of TV per week
- Average daily calorie intake for women = 1306 kcal
- Average daily calorie intake for men = 1685 kcal
Lquid vs solid food calories
- Scientific evidence shows that although liquids count as calories, the body doesn’t
detect them the same way as it would detect solid food. - When people eat calories in the form of solid food, they naturally compensate by
reducing the rest of their food intake. But when people ingest liquid calories
(alcohol, juice or soda), they don’t compensate for them by eating fewer calories. - The mechanisms controlling hunger and thirst are completely different, and liquids
— even if they contain calories — don’t seem to satisfy hunger even if they quench
your thirst. - Fluid calories do not hold strong satiety properties. “When the number and type of
calories are the same, the calories in liquid form won’t suppress ghrelin as
effectively as if the same calories were in solid form,” says David Cummings,
Associate Professor of Medicine at the University of Washington. - Fortunately, fluids with food in them, such as soups, are very satiating
