Nutrition 12 ch 7
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How is "overweight" defined?
Being too heavy for one's height.
BMI of 25 to 29.9
How is obese defined?
BMI of 30 or greater.
What is considered to be a healthy BMI range?
BMI of 18.5 to 24.9.
Does being overweight cause health problems?
Well, not directly. It is correlated with health problems and can increase the risk of health problems.
Being overweight does not automatically give you diabetes or heart disease, but it can make you more likely to develop these problems.
What is energy balance?
The amount of energy consumed compared to the amount of energy used.
Negative energy balance - weight loss. When you burn more calories than you consume ( you eat 500 kcal and burn 600 kcal you will lose weight ).
Positive energy balance - weight gain. When you consume more calories than you burn ( you eat 500 kcal and burn only 300 kcal you will gain weight ). The extra calories are stored in your body as fat.
What is a Calorie ( big C ), or, kcalorie?
A measurement of how much energy is in food.
Inches measure the length of a piece of paper, calories measure how much energy is in food.
Technically 1 Calorie ( big C ), or, kcalorie is the amount of energy required to heat 1 kg of water by 1 degree celcius. Or to heat 1 g of water by 1 degree celcius.
1000 calories ( little c ) = 1 Calorie ( big C ) = 1 kcal
What is a bomb calorimeter?
A device for measuring the amount of calories in food.
It is a chamber inside a a tub of water inside another chamber.
A piece of dried food is put inside the inner chamer and is burned. The burning food gives off heat that warms the water. A thermometer in the water tells how hot the water gets. This lets you find out how many kcals were in the food.
If there is 1kg of water in the bomb calorimeter and the temperature of the water went up 50 degrees celcius, then there were 50 calories in the food.
ATP is a source of energy for cells, like heart cells and muscle cells and liver cells.
ATP is made partially from electrons, it needs electrons for it to work.
Electron Transport Chain ( ETC )...
The electron transport chain make electrons available so they can be made into ATP.
It all happens in tiny things called mitochondria that are inside each cell. Electron carriers in the mitochondria move electrons back and forth across a membrane so that there are more built up on one side of the membrane than the other.
The build up creates kind of a pressure that makes them push back through at the end of the electron transport chain. They push through an enzyme called ATP Synthase and when they do... ATP is made.
Citric acid cycle / krebs cycle / TCA cycle...
The citric acid cycle pulls electrons off of things so they can be used in the electron transport chain ( ETC ).
Glucose gets made into pyruvate and pyruvate and pyruvate gets made into Acetyl-CoA which gets fed into the citric acid cycle.
Acetyl-CoA enters the citric acid cycle which makes electrons available for ATP ( energy for cells ) if you are active.
It can also be converted to fat if you are not active.
Acetyl-CoA is made from pyruvate.
Pyruvate is an acid in the body that can be...
- Made from:
- Glucose ( via glycolisis ), amino acids, glycerol
- Made into:
- Lactic acid ( used for energy during hard exercise )
- Acetyl-CoA ( goes into citric acid cycle to make electrons to make ATP )
Glucose is a simple sugar that comes from carbohydrates. The body uses glucose as fuel for the brain and red blood cells ( RBC ) by converting it ( through sevearl steps ) to ATP.
Glycolysis breaks sugar down into pyruvate.
- Glyco - sugar
- Lysis - break / cut
- Glycolysis = breaks sugar
95% of the fats we consume are triglycerides.
Triglycerides are made of 1 glycerol with 3 fatty acids attached to it.
The glycerol can be made into energy, fat or glucose.
The fatty acids can be made into energy or fat.
Proteins are made of many amino acids linked together in a chain. The specific order of the amino acids determine the protein's form and the protein's form determines the protein's function.
The amino acids in proteins can be made into: glucose ( but only a little ), energy, or fat.
There are 20 total amino acids - 11 nonessential and 9 essential.
Carbohydrates are made of sugars. Glucose, fructose and glactose are 3 of the sugars that can make up a carbohydrate.
In the liver fructose and galactose are converted into glucose.
Glucose can be used as fuel for cells or stored as fat.
How different things become energy...
This becomes that / this > that
Glucose > pyruvate > Acetyl-Coa > TCA > ETC > ATP
Glycerol > pyruvate > Acetyl-CoA > TCA > ETC > ATP
Amino acids > pyruvate > Acetyl-CoA > TCA > ETC > ATP
Fatty acids > Acetyl-CoA > TCA > ETC > ATP
Total energy expenditure ( TEE )
The total amount of energy used to keep you going.
It includes the energy used to digest food, keep your organs working, your cells functioning, as well as -doing- things like running, riding a bike, working, any kind of moving around.
Basal Energy Expenditure ( BEE )
- Total amount of energy your body uses to maintain basic ( basal ) functions, like keeping your organs working, cells functioning, it's all the automatic functions of your body, while awake, but not being physcally active and not digesting food. A measurement of this is taken 12 hours after digesting food.
Basal Metabolic Rate ( BMR )
The rate at which Basal Energy Expenditure ( BEE ) occurs.
Resting Energy Expenditure ( REE )
REE is the amount of energy the body uses while at rest, not being physically active and not digesting food. A measurement of this is taken 5 to 6 hours after eating.
This is a measurement of the amount of energy the body uses for automatic functions while not using any energy to digest food or being physically active.
Resting Metabolic Rate ( RMR )
The rate at which Resting Energy Expenditure ( REE ) occurs.
What conditions affect BMR?
Body weight, age, sex, growth rate, age.
A larger body will require more energy to keep it functioning. A more muscular body will require more energy. A younger, growing body will require more energy.
Lean body mass
All of the stuff in your body that is not fat ( bones, organs, muscles ).
What is NEAT?
Non-exercise activity thermogenisis.
It's the energy used for everything you do other than sleeping, eating, or intentionally exercising ( like jogging, bike riding ). It includes things like working ( your job ), cleaning your house, walking to work, cooking, etc.
What is the thermic effect of food?
The thermic effect of food ( TEF ) is the energy required to digest food and absorb it's nutruients.
This increase in energy use causes body temperature to go up a little bit for a few hours after eating. Different foods take different amounts of energy to digest and absorb.
If you eat 100 kcal of...
- 100 kcal fat - 5 kcal used to digest = 95 kcal net gain
- 100 kcal carbohydrates - 10 kcal to digest = 90 kcal net gain
- 100 kcal protein - 15 kcal to digest = 85 kcal net gain
What are adipocytes?
Cells that store fat. Adipose tissue is fat tissue.
Body energy stores, weight loss...
The body stores energy as fat and can use this fat later on to provide energy to keep the body going. If new energy is not added in by eating food the body will start to use fat supplies, after a while you start to deplete fat supplies and you lose weight.
How many calories to you have do skip to lose a pound of weight?
If, out of your normal diet, you skip 3500 kcals you will lose about 1 pound of weight.
Body energy stores, weight gain...
If you consume more energy than you use, it gets stored in your body as fat.
If you eat 3000 kcalories in a day and only use 2500 of them by working, exercising, etc, then the other 500 are stored as fat.
Energy hierarchy. Which energy sources are used first?
- Alcohol ( 7 kcal / g ) is used up right away, it's toxic to the body so it uses its energy then breaks it down.
- Protein ( 4 kcal / g )( really the amino acids from protein ) are used next since the body doesn't really have a way of storing them.
- Carbohydrates ( 4 kcal / g ) is used next, some of it is stored as glycogen in the liver and other cells.
- Fat ( 9 kcal / g ) is used last since it is not needed for anything specific and since it can be stored in large amounts.
So when you eat a meal, your body is going to use every other energy source from the food first and then just kind of store the fat if it doesn't need any more energy.
What is direct calorimetry?
A way of finding out how much energy a body uses by measuring the amount of heat that leaves the body.
Using energy produces heat. The more heat lost means the more energy is being used.
What is indirect calorimetry?
A way of measuring energy use by comparing how much oxygen is taken in to how much CO2 is exhaled.
Cells in the body use oxygen for energy and expell CO2 as waste. By comparing how much oxygen goes in to how much CO2 comes out you can tell how much energy is being used.
What are Estimated Energy Requirements ( EER )?
Estimate of the amount of energy that should be expended by someone given their age, sex, weight, height, and physical activity.
What are some health problems that excess body fat can contribute to?
Heart disease, high blood cholesterol, high blood pressure, stroke, daibetes, gallbladder disease, sleep apnea, respiratory problems, arthritis, gout, and; prostate, breast, uterus, prostate, and colon cancer.
Being overweight can also make it harder for the body to heal wounds and recover from surgery.
What are some health problems associated with being underweight?
With smaller stores of fat energy an underweight person is at a disadvantage during periods of starvation, they have less stored energy to keep them going.
Eating disorders such as bulimia ( binge and purge ) and anorexia ( person always sees themselves as overweight when they are not ) can lead to being underweight.
What is BMI?
Body Mass Index. It is a measurement of the relation of how tall someone is to how much they weigh.
If a person is a certain height then they should also be about a certain weight. Taller people can be heavier and still be at healthy weight. Shorter people will need to be at a lower weight to be healthy.
What are some situations where BMI may be inaccurate?
Muscle is heavier than fat. A very muscular person can be heavier and still not be overweight. A pergnant women will of course be heavier but can still be of healthy weight.
What is Bioelectric Impedence Analysis?
Electricity can pass through human bodies. Electricity will pass through fat more slowly than other tissues in the body.
A device is used that will pass a low level of electricity into one hand, through the body, and back into the device through the other hand. The device measures how long it takes to pass the electrical current through the body. The more fat the electricity has to go through the longer it takes.
What is the skinfold thickness test?
Body fat is stored just under the skin. Pinching a fold of this fat and measuring its thickness can give an idea of how much of a person's body is storing fat.
What is the underwater weighing method of determining body fat?
A person is weighed on land and in water ( where they weigh less ), the difference between the two weights can show how much of the body is body fat.
What is waist circumference method for determining body fat?
Measuring the thinest part of the waist, then measuring the thickest part of hip and dividing the waist number by the hip number.
Which overweight body shape is worse for your health, pear shape or apple shape?
Apple shape is worse for your health.
For people with most of their body fat stored around their abdomen the fat is visceral, it is stored deep in the abdomen which can cause problems for organs stored there as well like heart, liver, lungs.
People with pear shaped bodies have most of their body fat stored around their hips where it does not do as much damage to internal organs.
What kind of things determine where body fat is located?
Genes, smoking, alcohol consumption, physical activity, stress.
What is the set point theory of body weight?
Simply that most people have a set point at which their weight tends to stay once they've stopped growing ( after adolensence ).
This suggests that the body has built in mechanisms for keeping people from losing weight.
This would be to protect people from losing too much weight when they don't have enough to eat. There doesn't seem to be as much protection to keep bodies from gaining weight.
There are some genes associated with regulating body weight, how many of these genes are there?
About 300 of them.
What is ghrelin?
A hormone produced in the stomach that tells people to eat at certain times of the day.
Regulates body weight short term.
What is peptide PYY?
A hormone released in the GI tract after a meal in proportion to how much food was eaten that causes you to feel full ( increases satiety ).
Regulates body weight short term.
How does insulin affect hunger?
Insulin signals cells to take in glucose.
This reduces the amount of glucose circulating in the body.
- Regulates body weight short term.
- This increases hunger.
How can levels of nutrients circulating through the body affect weight short term?
A decrease in the amount of nutrients circulating in the body can cause hunger.
How does leptin affect body weight long term?
Leptin is a hormone relased by fat cells in the body.
When stores of fat decrease it sends a signal to the brain telling the body to eat more to bring body fat back up to previous level.
When fat stores increase the same leptin tells the brain to tell the body to use more energy and eat less food.
How does insulin affect body weight long term?
The more body fat a person has, the more insulin they produce. The more insulin they produce the more glucose is taken up by cells where it is stored as fat.
What is thrifty metabolism?
Some people can eat few calories but still gain weight. It is thought that these people have thrifty metabolism, so that more of the energy they take in is deposited in fat as energy stores.
This could be a kind of survival mechanism that helps a person last longer when food runs out.
To lose 10% of body weight in 6 to 12 months, how much weight would you need to lose per week?
.5 to 2 lbs. per week.
10% body fat reduction is achievable for most people.
How many calories is 1 pound of fat equal to?
A pound of fat is equal to about 3500 kcalories.
To lose one pound in one week you would need to decrease kcalorie intake by about 500 kcalories a day or increase activity by 500 kcaolories per day. Or a combination of the two.
What are some basic steps to weight loss?
Eat less, exercise more, modify behavior.
What steps can be taken to gain weight?
Eat more, and do strength training.
How do food exchange lists used for dieting?
Food exchange list diets have dieters pick a certain number of servings from different groups for different meals.
How do prepared meals and drinks help people lose weight?
All the meals a person is allowed to eat is prepared by somone else and food intake is controled.
How do low fat and no fat diets work?
Fat intake is simply decreased.
How are low carb diets supposed to work?
Carbs are sugar, sugar in the diet increases the release of insulin which tells the cells to open up and store the sugar as fat.
Decreasing the carbs is supposed to decrease the insulin release and decrease the storage of fat.
How do some -prescription- weight loss drugs work and why are they not always a good idea?
Meridia affects the activity of brain neurotransmitters serotonin. Serotonin is released after eating and helps you feel full, then the body reabsorbs it and the feeling of fullness goes away.
Meridia slows down or inhibits the reabsorption of seretonin so that the feeling of fullness lasts longer.
What is Alli, how does it work?
Alli is a non-prescription over the counter drug that disables lipase so that it cannot break down triglycerides into fatty acid and glycerol.
Since the triglycerides are not broken down the fat does not get absorbed by the body and stored.
Intstead it's just pooped out, greasy fat just straight up pooped out. Gross.
How does gastric bypass surgery affect weight loss?
The top of the stomach is sealed off and intestine is attached to it and redirected to the rest of the small intestine. The result is a smaller stomach. The rest of the stomach is still there, it's just that food never enters it.
What is gastric banding and how does it work?
With gastric banding a band is placed around the upper portion of the stomach so that food cannot pass through as quickly or easily as normal. The result is that you simply cannot eat as much food at one time.
What is liposuction and how does it affect weight loss?
Essentially a big, hollow needle is inserted into an area of local fat deposit and the fat is sucked out. This cannot be done in all parts of the body though, it's mostly for cosmetic appearances and does not promote weight loss.
How do you calculate BMI using metric system ( kg and meters )?
- weight in kg
- height in meters 2
A person weighs 60kg and is 1.7m tall...
How do you calculate BMI using imperial system ( lbs. and inches )?
- weight in lbs.
- -------------- x 703
height in inches2
A person is 5'6" tall ( 66 inches ) and weighs 160lbs.
- ---- x 703
- 4356 ( 66 x 66 )
= 25.82 BMI
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