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Energy balance Energy Kilojoules (kj) =metric Kilocalories (kCal)= imperial measurements (often referred to as calories) 1 kilocalorie = 4.2 kilojoules (4.18) (higher number can assume in kilojoules (e.g. 4000 daily intake probably in kilojoules) 1 kCal of heat = energy required to heat 1kg of water by 1 degree Celsius Measured in a bomb calorimeter - determined total amount of energy in a food -set to mimic our metabolism

ENERGY STORAGE CHO - Glycogen stored in skeletal muscle and liver - Minimal conversion to lipid - Lose water attached to glycogen (quick weight loss that we see), not loss of body fat which takes much longer (water is stored with every glycogen) - By consuming a low CHO diet, will use up liver and muscle glycogen stores quickly, as soon as we start using muscle glycogen for energy, we release that water (that water is lost either in urine, respiratory etc); this water attached to glycogen is the quick weight loss. Not loss of body fat, takes much longer - If excess CHO intake: almost impossible (CHO main energy substrate) will convert a tiny amount of that excess into fat (denovo lipid genesis) stays in liver and used up eventually How do we get fat then? Too much fat and too little physical activity in simple terms PROTEIN -not stored in the human body -circulating & recycled amino acids are a source of protein building blocks FAT -triglyceride in adipose tissue & IM (intramuscular e.g. marbled meat) -100 % absorption & metabolism

Hierarchy of macronutrient oxidation 1. Alcohol -alcohol pushing to cue and says me first!!! More alcohol you have in system and the more often then less fat you’ll be burning for energy and the less CHO burning for energy -not stored in the human body - 1st to be oxidised for energy 2. -

CHO Glycogen in skeletal muscle and liver Limited stores AND readily oxidised Rapid turnover (need to be bed ridden and force fed CHO to have excess, very hard to do) - Main energy macronutrient in human body - If no alcohol in system, CHO is first to be used - If high CHO intake, than less fat using 3. -

Protein NOT stored in human body Used to generate ATP in body Some muscle tissues breakdown amino acid oxidation  energy

4. -

FAT Triglyceride in adipose tissue Last to be oxidised in the hierarchy Emergency reserve, twice the energy density as protein and CHO, little goes a long way

Nutrient Partitioning Definition - The channelling of food carbon into protein, CHO and fat - Protein and fat easiest to measure How would you measure protein ‘deposition’? –nitrogen balance (in urine) if positive nitrogen balance or just nitrogen balance (if in higher than out, enough protein to be used for all processes Why is CHO deposition hard to measure? - Measured as Lean vs. Fat mass gains - Evidence suggests LM is (genetically) programmed but not FM -  Affects body composition - CHO not mentioned because constantly turning it over so to hard to measure, reabsorption in renal tube also

GRAPH ON LECTURE -initially overfeeding leads to  lean mass (LM) -if overfeeding continues -LM wt gain gradually declines -taken over by  fat mass (FM) Then hyperphagia (excessive eating) (&FM) until LM catches up to a genetically predetermined amount -LM (but not FM) is genetically programmed? - the higher the BMI, the more fat you start to accumulate -the lower the BMI (losing fat) losing fat first -if gain weight, gain muscle first, then fat follows; vice versa Nutrient partitioning Nutrient partitioning in underfeeding -evidence from semi starvation studies -e.g. Minnesota semi starvation study -loss & recovery of lean vs. fat mass

ENERGY COMPONENTS -Energy balance -Energy IN vs. Energy out -Dietary components Ein -Energy components Eout TEE (total energy expenditure) =BMR (Basal metabolic rate) (BEE), TEF (the thermic effect of food), PAL (physical activity level), NEAT (non exercise activity thermogenesis e.g. energy used through fidgeting) ENERGY IN COMPONENTS ** do not use WHO (2003) ranges of population nutrient intake goals  use: Nutrient Reference Values, 2006* Macronutrient balance; Acceptable macronutrient distribution range (AMDR) CHO 45-65% E total -type of CHO more important than % E total PRO 15-25% E total -no consensus -suggested TEE….weight gain > overweight, obesity? (but depends which excess macronutrient the excess energy is coming from) - -ve: intake < TEE…weight loss > malnutrition (poorly nourished, underweight, expending more energy than consuming) Energy Intake -food, beverages, some supplements (e.g. sustagen, fish oil) only because 100% fat and depends on how much we take Total energy expenditure (TEE) 1. Basal energy expenditure BEE (BMR or RMR: 60-75%) 2. Diet induced thermogenesis (DIT or TEF: 5-10%) 3. Energy cost of physical activity (PAL: 20-40%) 4. And now… NEAT (contribution currently unknown) - Physiological status: Growth (35% new born to 1-2% childhood/ adolescent, pregnancy, lactation, injury (not covered in this topic) Energy requirements Definition:

“intake to balance EE when body size & physical activity consistent with long term good health” Factors influencing E requirements: 1. Basal energy expenditure BMR-basal metabolic rate BEE-basal energy expenditure -fasting metabolic rate -12 hours post prandial -measured on site -following overnights sleep -subject at rest -thermoneutral environment -ambient temp above or below which BMR rises = lower critical temp – 22-27 degrees RMR- resting metabolic rate (or written as) REE- resting energy expenditure -close approximation of BMR -fasting usually -can overestimate BMR by up to 10% (not temp controlled) -measured off site -12 hours post prandial (after a meal) -following overnights sleep -subject at rest for ½-1 hour -not always thermonetural environment -Measurement of BMR or RMR -indirect calorimetry (portable method) - ventilated hood method - mouth piece and nose clip method - volume and rate of oxygen used (VO2) - Volume of rate of carbon dioxide produced (VCO2) - Respiratory exchange ratio (RER) = respiratory quotient (RQ) - if RER = 1.0 > CHO - if RER = 0.7 > Fat 2. Thermogenesis -thermic effect of food (TEF) - approx. 5-10 % of energy intake

-diet induced thermogenesis (DIT) -Post-prandial thermogenesis (PPT) -specific dynamic action of food a) obligatory thermogenesis - to supply E for… Digestion, absorption, transport, storage, metabolism Factors influencing E requirements -main component =energy expended processing food consumed -mostly measured as ^ E expenditure above BMR -measured 3-6 hours post ingestion -measuring conditions & apparatus same as for BMR -measures energy expenditure in KJ/minute -measured as increase in BMR after feeding - Added to E expenditure from BMR - Different energy expenditure (E cost) processing each of the macronutrients -Thermic effect (E cost) of each macronutrient -CHO: 8% of the energy content (of glucose) -CHO induced thermogenesis =mainly E cost of glycogen synthesis -Approx 5 % of energy content of glucose used up in substrate cycling e.g. Glucose ↔ Gluc-6-p; lactate > Glucose -and ATP cost of active transport (SI absorption of glucose) -E cost of CHO oxidation is minimal by comparison Factors influencing E requirements FAT: 2 % of the energy content (of fat) -Fat induced thermogenesis =mainly E cost of fat storage -Esterification of free fatty acids to triglyceride -E cost of fat oxidation is minimal by comparison PROTEIN: 25 % of the energy content (of protein) -PRO-induced thermogenesis = mainly E cost of… -deamination (nitrogen removal after SI absorption) -Protein synthesis from amino acids (cost of synthesis of peptide bonds) – E cost of protein oxidation is minimal by comparison ALCOHOL: 22% of the energy content of ethanol -ALC-induced thermogenesis = mainly E cost of… Alcohol metabolism in the liver

Therefore in a mixed diet…. -High Protein, high alcohol intake -relatively high E expenditure via TEF -High fat intake - relatively low E expenditure via TEF -High protein, high alcohol intake relatively high E expenditure via TEF -High fat intake relatively low E expenditure via TEF b) Facultative thermogenesis -Temperature increase after eating -mainly in brown adipose tissue (BAT)? (mostly seen in babies, back of the neck, they have a large surface area for their weight) -food consumption activates UCP-1* in BAT -Noradrenaline-meditated (sympathetic nervous system) -heat production instead of stored energy or energy production -“non shivering” thermogenesis -WASTED energy (but component of energy expenditure) -Particularly relevant to excess CHO & PRO intakes - therefore ^ amount food consumed > ^ TEF > ^wasted energy? -Yes for CHO & PRO but NO for FAT 3. Physical activity level (PAL) PAL-physical activity level -multiples of BMR (WHO classifications) -Not KJ/min or MJ/day (PAL does not have units) -builds on BMR (rest + physical activity) -E cost of physical activity (leisure + exercise) -E cost measured with indirect calorimetry PAR- physical activity ratio -measured as KJ/min or kcal/min -E cost of physical activity for a specific time span -often used in research for physical activity diaries -divides day into 5 or 15 mins intervals for physical activity records *if estimating use PAL, if measuring use PAR PAL classifications -prior to 2006, WHO 1985 was used for PAL classifications, not used anymore because our lifestyles have changed (expend less energy now than what we used to e.g. people jobs)

NHMRC, 2006 Sleeping Bed rest Very sedentary Light activities Moderate activity Heavy activities Vigorous activity

? 1.2 1.4 1.6 1.8 2.0 2.2

Measurement of E expenditure Metabolic equivalents (METs) –Just based on oxygen consumption Physical activity can be classified by…. -level of intensity -degree to which it increases energy expenditure 1 MET= the energy (oxygen) used by the body -Average seated resting oxygen (O2) consumption -Approx 250ml O2 per min (approx. 3.5ml O2/kg body wt/min) The harder your body works during the activity -therefore, the higher the MET -The higher the exercise intensity AND energy expenditure Factors influencing E requirements 4. NEAT (% of energy intake unknown) -Non-exercise activity thermogenesis -Energy expenditure other than formal sport or exercise - Fidgeting, dancing, playing a musical instrument, gardening, house work

Estimates of E requirements/expenditure BMR, RMR  BEE (basal energy requirements) Based on estimated BASAL ENERGY EXPENDITURE Prediction equations (adults) (don’t have to memorise equation)

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Prediction equations (adults) (don’t have to memorise equation)– Harris-Benedict equations (kJ/day) ♀2741+(40.0xW)+(7.7xH)-(19.6xA) • ♂278+(57.5xW)+(20.9xH)(28.3xA) – Schofield equation (adults 18-30; 30-60yrs) (MJ/day) ♀ (18-30yrs) (0.062 x W)+2.036; (30-60yrs) (0.034 x W) + 3.538; (>60yrs) (0.038 x W) + 2.755 ♂ (18-30yrs) (0.063 X W)+2.896; (30-60yrs) (0.048 x W) + 3.653; (>60yrs) (0.049 x W) +2.459

Then multiply the BEE by PAL= TEE (total energy expenditure) -Which components are missing from this calculation? NEAT, diet induced thermogenesis (if we know their dietary intake) important to remember Measurement of E expenditure -non- calorimetric methods useful for free living populations -doubly labelled water (DLW) -heavy water -2H2180 (Deuterium oxide with a twsit) -expensive & labour intensive -usually research only -Bicarbonate tracer method (H13CO3) -13C bicarbonate tracer -stable isotope radioactive carbon -non invasive but labour intensive -less expensive than DLW -usually research only Measurement of E expenditure Tri-axial; accelerometry -3D movement -up & down (radial) -backwards and forwards (axial) -Side to side (tangential) -expensive -mainly used for research Pedometry -2D movement -radial & axial -pedometer step counter

-calories burned -inexpensive

Energy metabolism Respiratory Exchange ratio (RER) Respiratory Quotient (RQ)

-Non protein RER- protein not included in this measurement EXAM question: difference between basal and metabolic rate

Carbohydrates Simple carbohydrates CHO Category Sugars Monosaccharides (1 unit)

Name

- fructose -glucose -galactose

Digestibility Sources

D

- table sugar - from cane and

- sucrose (glucose + fructose) - lactose Disaccharides ( 2 (glucose + units) galactose) - maltose (glucose +glucose)

D

- sorbitol - xylitol - lacticol -galacticol, inositol, mannitol

F

Sugar alcohols (polyols)

Sugar acids

- fruit, vegetables, honey -onions, grapes, honey -cherries, honey

F

beet - milk only - starch hydrolysis sprouted wheat & barley  malt extract  brewing - low joule sweetener - occurs in some fruits e.g. cherries - chewing gum, pharmaceuticals, oral health products - low joule icecream & chocolate, baked goods - ‘sugar-free’ mints (see example) - constituent of pectin - rarely occur freely naturally

D= digestible in the small intestine (i.e available) F= fermentable in the colon (large bowel) (i.e unavailable) Fructose-facilitated diffusion (slower to absorb across the intestinal wall e.g. if you ate a lot of honey or 5 nectarines at once could get diarrhoea) where as glucose actively transformed and faster

Sugar polyols example -Wrigley’s eclipse mints (gas build up if have a lot of these) -sugar free (artificially sweetened) Nutrition information:  Serving Size Package 17  Serving Size 2g MADE OF: HUMECTANT (420)*, SORBITOL, FOOD ACIDS (296, 330), ANTICAKING AGENT (470), FLAVOUR, SWEETENERS (950, 951), COLOUR (129)  *420 = Sorbitol

Chemical structure Oligosaccharides (sugars) - a ‘few’ saccharides (sugars) - typically 3-10 monosaccharides in a polymer chain - components of glycoproteins (protein + glucose) - e.g. glycosylated haemoglobin (HbA1C) - monitors long term (approx. 3/12) blood glucose control) - desirable < 7% - higher HbA1C > ^bl glucose > poor bl glucose control over time

components of glycolipids (lipid + glucose) e.g. outer surface of cell membranes -glucose attached to phosphor-lipid molecules

Complex carbohydrates - polysaccharides > 10 monosaccharides -‘many’ saccharides (sugars) -starch is a polysaccharide Starch -storage form of CHO in plants - potatoes, bread, pasta, rice, bananas -ANIMAL equivalent is GLYCOGEN 3 TYPES: -Amylopectin -Amylose -Resistant starch e.g. un-ripe bananas Digestible starch: Amylopectin -long chains of glucose molecules with many branches -branches make Amylopectin more soluble Large loose molecules -more soluble in water + heat Digestible: Amylose -long unbranched chain of glucose molecules -‘string of pearls’ -harder to digest -strings form dense clumps -insoluble in H2O until heated Resistant to digestion Resistant starch -chemical form of starch -crystalline structure -resistant to digestive enzymes

-amylase, disaccharides -behaves like dietary fibre -fermented in large intestine (colon) Food sources Resistance starch occurs… -physiologically e.g. unripe bananas -cooking & chilling e.g. potato salad e.g. hospital food service? Other examples? Health benefits -slowed GE rate -how does slowed GE have health benefits? Which lifestyle diseases might be helped? Diabetes

Chemical structure Non-starch polysaccharides (NSP) -dietary fibre -Insoluble (‘roughage’) definition: parts of the plant cell wall not digested by human digestive enzymes -cellulose -hemicellulose -lignin; insoluble in H2O & human digesta Structure & function Non-starch polysaccharides (NSP) -dietary fibre -soluble -incorporated into modern definition -includes cell wall components (insoluble fibre) & non-cell wall components; gums, pectin’s, mucilage’s soluble in H2O & human digesta -forms a gel in SI -slows nutrient absorption -advantages?

Food sources -soluble fibre -pectin’s : apples, pears, food thickener, jam seta, Metamucil Foods sources & function Soluble fibre -Gums & mucilage’s -from stems & seeds of tropical trees and shrubs -‘gum Arabic’ from Acacia (wattle) sap -Carrageenan (seaweed) -Polysaccharides & glycoproteins -Thickener, homogenizer & stabilizer - ice cream -Cottee’s topping -Confectionary e.g. snakes, lollies, jelly babies Diseases related to CHO metabolism - diabetes type 1 and 2 - reactive hypoglycaemia - Lactose intolerance - Fructose intolerance (Multi-faceted disorder) - Galactosaemia; NB lactose > glucose + galactose, therefore dairy foods should be avoided - Glycogen storage diseases

Glycaemic Index (GI) -previous CHO food categories -simple or complex CHO (does not translate how CHO’s work in the body) -Sugars= simple; rapid absorption, quick rise In BGL -Starch= complex –slower rise in BGL Now outdated -replaced by Glycaemic Index Glycaemic Index Definition: -ranking of CHO foods based on the postprandial blood glucose response over 2 hours -area under blood glucose response curve compared with a reference food (AUC) -white bread or glucose

Limitations of these? -GI pure glucose arbitrarily set at 100 -tested in equivalent CHO amounts (50g CHO)

Glycaemic Index -food tested 2-3 times per person -mean value calculated -reduces effect of day-day variation in blood glucose responses -approx 10-12 healthy people tested/food -GI of food = mean value of group -SD can be more than 12 GI points High GI  70 e.g. brown rice (boiled) GI=87 -NB considerable variation within rice strains (don’t get confused by rice example, also white bread etc) Medium GI: 56-69 e.g fresh sweet corn (boiled) (GI=60) Low GI  55 e.g. dark chocolate (Dove) GI=23 **Low GI to keep fuller for longer How can some foods have a GI > 100?

e.g. maltose GI =105 Hint: maltose is a disaccharide Factors affecting GI Variety of starch -amylose: amylopectin ratio -more amylopectin, higher GI -Why? Think about the branding Cooking -time and method e.g. streamed vs boiled vs baked - The shorter the amount of cooking, less time exposed to heat and moisture, less pre digestion Processing -Physical processing of the food e.g. instant oats versus traditional, cut oats starch broken down much more rapidly, traditional oats take longer to cook therefore GI lower than those cook for 90 seconds because of the physical treatment of the oat flakes Effect of fibre on GI -Fibre slows (decreases) gastric emptying rate -Fibre slows (increases) intestinal transit time BUT -finely ground wheat fibre -e.g. processed wheat fibre -e.g. Wonder white bread -minimal effect on GI of bread -therefore similar GI to white bread -soluble and insoluble fibre Glycaemic Index Uses: -Glucose control/management –Type 2 diabetes Slows GE rate > decreases BG response -satiety – weight management Lower GI > improved satiation AND satiety -Sports nutrition Low GI before endurance event? 30 mins before (not much different if have HIGH GI or LOW GI before endurance event) -High GI after endurance event? Replenish muscle glycogen stores quicker

Glycaemic Load (GL) -GL is GI applied to mixed meals -a weighted mean of the GI of the CHO foods in a meal Per CHO food -GI ranking x % total CHO (in that food serve) -GL is affected by AMOUNT of CHO in a meal

Low GI (or GL) and health Type 2 diabetes -Low GI foods (Low GL meal) produce lower post-prandial blood glucose responses Weight management -Low GI foods MAY increase satiety. How? Signals brain that your still eating, because of slow release of CHO after eating -therefore MAY bring feeding episode to a quicker close CV disease (sugar and the heart) -lower plasma triglycerides -Due to lower post-prandial blood glucose concentrations Sugar and (heart) health How does sugar increase ^^ the risk of heart disease -Carbohydrate-induced hyper-triglyceridaemia? Sucrose & fructose elevate fasting serum triglycerides (TAG) -SHORT TERM effect Dose response effect NOT KNOWN -i.e how much is too much?

-LONG TERM studies show no effect of sucrose & fructose on serum TAG in non obese humans -BUT evidence insulin resistance/abdominal obesity linked to CHO-induced hyper...