Nutrition Exam 3
You just ate 2 slices of a medium pizza for lunch. Here is the nutrient analysis: 21 g of protein, 75 g of carbohydrates, 18 g of fat, and 4 g of fiber. How many kcals is in this meal? Calculate the percent kcals coming from fat.
(21 * 4) + (75 * 4) + (18 * 9) = 546kcals (18*9) = 162 Kcals / 546 kcals = 29.7 % Don't include the fiber in the calculations because it is already included in the carbs.
Describe the common characteristics of all vitamins. Then describe similarities and differences between fat- soluble and water-soluble vitamins.
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What weight would health experts set as a safe and reasonable goal for Sonia to attain from a weight loss diet? (Sonia should lose about ___ % of her body weight over a 6 month period or ____ lbs/week. See pg. 283)
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What are the three basic processes of energy metabolism? Briefly describe each step.
1. Glycolysis - process of breaking down glucose and turning it into pyruvate. 2. Intermediate Step - pyruvate to acetyl CoA 3. TCA cycle - a way to take small molecules like acetyl CoA and tear H's off of them 4. ETC - a way to take all of the H's from steps 1,2,3 and use them to make ATP
Acetyl CoA
2 carbon compound that CoA molecule is attached to
Pyruvate
3 carbon compound that plays a key role in energy metabolism
Pellagra was in epidemic proportions in this country around 1910-1930. What are the symptoms of this disease? What were the dietary conditions, which precipitated this disease? What was the significance of a low protein diet? How did our public health officials resolve the situation so that pellagra is now eradicated in this country?
4 D's. Diarreha, dermatis, dementia, death. Almost all sources of niacin come from a protein-rich food. Fortify grains with it.
As defined by the Center for Disease Control (CDC), what is the approximate prevalence of adult overweight plus obesity combined for US adults?
68%
Oxaloacetate
A carbohydrate intermediate (product used to make another product) of the TCA cycle
List all possible fates of acetyl CoA? Why can't acetyl CoA be used to make glucose?
Acetyl CoA will be sent through the TCA cycle when energy is needed, can be sent to fermentation if no O2, or can be sent through fatty acid oxidation.
Ketogenic amino acids
Amino acids degraded to acetyl CoA
Glucogenic Amino Acids
Amino acids that can make glucose via pyruvate or TCA cycle intermediates
What are the key features of the different forms of eating disorders discussed in class and the text?
Anoexia - loss of body weight, fear of eating/gaining weight, can't see own body correct Bulimia -vommiting/diarrhea/excess workout, bingeing and purging Binge - bulimia but no method of getting rid of excess calories Female athletic - some sort of restrictive eating, may not be intentional, experience ammonia (loss of period) -change of hormones-osteoporosis-bone fractures NONE OF THESE ARE CHOICES - ALL PSYCHOLOGICAL DISEASES
Many health experts describe our environment here in the U.S. as "obesogenic." Why?
Because everywhere you go there is FOOD. Whether it is sight or smell or efficiency it has become a serious problem in our environment. Demand for physical activity has decreased and abundance of food has increased.
What are two other criteria (besides BMI) which should be used to determine healthy body status in an individual? Why is BMI not a perfect indicator of health risks? Some people need more body fat; explain.
Body fat percentage & waist circumference. Because it does not put into account if it is muscle or fat, an athlete would generally weigh more because they have more muscle. Some people need more body fat like during pregnancy to support the growth of the fetus, also if they experience extreme cold temperatures to maintain a healthy temperature.
What are the end products of metabolism?
Carbon Dioxide (CO2), Water (H20), Energy (ATP)
List the physiological fuel values for carbohydrate, protein, fat, and alcohol?
Carbs: 4 Protein: 4 Fat: 9 Alcohol: 7
Anabolic Reactions
Chemical reactions in which small molecules are put together to build larger ones. Ex: making glycogen, triglycerides, and proteins REQUIRE ENERGY
Coenzyme
Complex organic molecules that work with enzymes to facilitate the enzyme's activity. Many have B vitamins as part of their structure
Free Radicals
Compounds with unpaired electrons that can cause cell damage, chronic disease, and aging.
Where was beri beri first observed? What does beri beri mean and how did it get its name? Why is beriberi a potential problem in populations that consume most of their kcals from "polished" rice? Americans eat lots of polished rice; yet do not get beriberi, why?
Deficiency of thiamin. It will cause populations to become weak, have nerve damage, muscle wasting, and edema. Beri beri comes from all sources of grains.
Describe the four components of a healthy weight maintenance or weight loss program. Now list factors identified as important when developing eating plans for weight loss and maintenance of a healthy weight. What is a reasonable reduction is kcals/day (either from food or exercise) for a healthy weight loss diet?
Diet, Physical activity, Behavior modification, Social Support. Eat low energy dense foods, small portions, avoid empty calories, drink water. Eat high volume low calorie foods, include a source of protein and healthy fat at each meal.
True or false and explain? There are no health risks associated with being underweight (BMI<18.5), especially in women.
FALSE. They won't be able to preserve lean tissue - which makes it hard to fight off diseases. It messes with periods and can lead to infertile. May give birth to an unhealthy baby. Osteoporosis - more prone to bone fractures.
Thermic effect
Fats: Low Proteins: High Sugar: Low Fiber: High
ETC
Final pathway in energy metabolism that transports electrons from Hydrogen to Oxygen & captures the energy released in bonds of ATP
If a person went on a starvation regimen, what would be the source of glucose for the first day? Subsequent days?
First they would the stored glucose. Then whatever is still in your body that hasn't been converted into body fat. Then it would use the muscles.
If Sonia ate the same amount of kcalories from her flounder, her olive oil, and her rice, which would have the highest thermic effect of food?
Flounder
Describe how we measure energy expenditure in humans.
Generation of heat, thermogenesis. 3 components: Physical activity, thermic effect of food, BMR.
14. Some amino acids, like alanine, are glucogenic. What does this mean? When is it important for glucogenic amino acids to be metabolized to glucose? Not all amino acid are glucogenic. What are the others?
Glucogenic amino acids can be converted into glucose because it enters into pyruvate. When you need glucose (low blood sugars). Ketogenic, can only be converted into acetyl CoA.
How many carbons are there in the following molecules: glucose, glycerol, fatty acids, alcohol, pyruvate, and acetyl CoA?
Glucose: 6 carbons Glycerol: 3 carbons Fatty Acids: 2 carbons? Alcohol: 2 carbons Pyruvate: 3 carbons Acetyl CoA: 2 carbons
List the components of behavior modification strategies that can be used to assist in sustained behavior change in order to lose weight or maintain a healthy body weight.
Goal is to increase energy expenditure and decrease energy intake. Become aware of behaviors, change behaviors, cognitive skills, personal attitude, and support groups.
What factors or characteristics can raise basal metabolic rate (BMR) and what factors can lower basal metabolic rate? When you eat a very low kcal intake (say, cut your calories in half) from your usual kcal intake for a few days, what happens to your BMR?
High BMR: lean BMI, growing people, fever, high stress Low BMR: little lean BMI, sleep, fasting, malnutrition Your BMR slows down.
Briefly, what is the difference between hunger, satiation, satiety, and appetite? Does the phrase "feeling fuller for longer" refer to satiety or satiation?
Hunger: Physiological need for food Appetite: sight or aroma of food, routines, stress, emotions, not physiological signals Satiation: feeling of satisfaction during a meal, halts eating, can't eat another bite Satiety: full and satisfaction after a meal
List the benefits of physical activity for managing body weight.
Increases lean body mass, increases BMR, improves cardiovascular fitness, decreases blood pressure, decreases insulin resistance, increases feelings of well being and self esteem.
Explain how the concept of plate management could be used to help with weight loss. What food group is emphasized in this particular plan?
It will increase your intake of nutrient-dense foods and decrease your intake of energy-dense foods. Vegetables are emphasized.
When metabolizing margarine (fatty acids and glycerol), would it be converted to pyruvate before entering the TCA cycle?
It would be broken down into fatty acids and glycerol. The glycerol would be converted into pyruvate, the fatty acids would be oxidized into acetyl CoA
Why is it that in untreated diabetes the urine and breath can smell slightly sweet, sort of like acetone? Could the same thing happen in starvation? Could the same thing happen with an extremely low carbohydrate diet? Explain.
Ketosis can lead to sweet breath. Yes because you are producing ketones. And yes because your only sources of energy then is coming from protein and lipids.
13. If a person were to fast for a day or so, describe what happens to the energy stores within the body and how the body would deal with this. See the PowerPoint and also the textbook to describe each step in how the body would adapt.
LOOK AT POWERPOINT
Comment on the effects of nutrient composition of a meal on satiation and satiety. Define low energy density. Explain the difference between dietary fat having a low satiation in the stomach, verses fat producing satiety signals when in the small intestine. What nutrient is considered most satiating?
Low energy density = feel more full for longer. Fat provides little satiation during a meal, but produces strong satiety signals once it enters the intestine. Protein is the most satiating nutrient.
What does a bomb calorimeter measure? Briefly describe how it works.
Measures how much heat is released which determines the potential energy in the food.
Fatty Acid Oxidation
Metabolic breakdown of fatty acids to acetyl CoA
Glycolysis
Metabolic breakdown of glucose to pyruvate. Does NOT require oxygen (anaerobic)
Describe in a brief sentence the roles of niacin (NADH) and riboflavin (FADH2) in ATP production.
NADH- makes 3 ATP FADH2- makes 2 ATP
Can fatty acids from body adipose tissue produce glucose for the blood when blood glucose is very low? Why or why not?
NO - the glycerol can though because it goes into pyruvate and can be reversed into glucose. But fatty acids go into acetyl CoA
Anerobic
NOT requiring energy
If someone is in negative energy balance, what changes would you expect to see in their body? How about if they are in positive energy balance?
Negative balance = losing weight Positive balance = gaining weight
Sarah, a college student, states she wants to eat more during the mid-afternoon because she knows food is energy and she feels she needs some extra pep. Explain if this is likely to work for her.
No - energy doesn't mean "pep" we need to eat nutrient dense food in order to get the energy needed.
Ketones
Organic molecule containing a carbonyl group =C=O bonded to two hydrocarbon groups. Produced during the incomplete breakdown of fat when glucose is not in the cells
Is your body an apple or a pear? So what, why is this important? What are the cut-offs in terms of adult waist circumferences and risk for increased chronic diseases?
Pear. It is a potential indicator to diseases. Women: 35inches. Men: 40 inches. Risk for chronic disease is when BMI goes below or above 18.5-24.9.
You expend energy (ie. Body uses food for fuel) in three categories. List these categories and define them. For the average semi-sedentary American, what category is responsible for the most calorie expenditure? How do you calculate the thermic effect of food?
Physical activity: exercise Thermic effect of food: energy used in digestion, absorption and distribution of nutrients. BMR: energy needed to maintain life when is at complete rest Basal metabolism is the category most responsible for calorie expenditure.
What are the health risks associated with obesity?
Premature death, heart disease, diabetes, cancer, arthritis, quality of life, costs
Catabolic Reactions
Reactions in which large molecules are broken down to smaller ones. Ex: glycogen - glucose, triglycerides - glycerol & fatty acids, protein - amino acids. RELEASES ENERGY
Aerobic
Requiring energy
Sonia has struggled with overweight throughout her childhood and adult life. Zoom ahead 20 years and Sarah becomes obese in her 30's. Explain the differences between fat cell development between Sonia and Sarah. Explain why Sonia will likely have more difficulty losing weight than Sarah will. Once Sonia loses her weight, how will her energy needs be different than someone of the same weight and height who never had a weight problem? What strategies could help Sonia to maintain weight loss have been utilized by other successful weight loss maintainers?
Sarah has more fat cells and they are larger in size, whereas Sonia just has a greater number of fat cells because she developed them during childhood whereas Sarah developed them in adulthood. Sonia will have a more difficult time losing weight because she has more&larger fat cells, so although she can decrease the size of the cells the amount she has will not decrease so it will be harder for her to maintain. Sarah on the other hand has less fat cells but larger size so it will be easier for her to lose weight because she will just decrease the size of the fat cells and have a healthy amount of fat cells (same as she began with). She is battling against an enzyme that wants to store fat. Diet, physical activity, behavior modification, and social support can help be successful in losing weight. Emphasize low energy dense foods, eat small portions, avoid empty calories, drink water! High-volume, low-calorie foods. Include a protein at every meal to make you feel more full.
TCA cycle
Series of metabolic retains that breakdown molecules of acetyl CoA to carbon dioxide & hydrogen atoms
What is the misconception in this student quote? "The less dietary fat I take in, the less body fat I will have."
Some dietary fats are essential. Also, not just fat goes towards body fat.
What methods described in the text and class should be utilized to preserve vitamin content of foods when cooking?
Steam the vegetables in small amounts of water, boil the water then add the vegetables, use the water in your dishes... if possible.
Metabolism
Sum total of all chemical reactions that go on in living cells. Energy metabolism - all reactions by which the body obtains & expends the energy from food
What fat distribution pattern is associated with less risk of chronic disease and what fat distribution pattern is related to higher risks?
The "apple" fat distribution is associated with higher risk of chronic disease, "pear" fat distribution is associated with lower risk of chronic disease.
15. What is oxaloacetate (OAA)? What does it mean that you need some carbohydrate to fuel the burning of fat?
The last molecule in the TCA cycle that is needed to continue the cycle. You need something to continue the TCA cycle... check PP
Explain how the energy density concept could be useful in weight management and how to use it to change the energy density of a meal.
The less energy-dense meal you have the more nutrient-dense meal you have. It will still make you feel full providing you with more nutrients and less calories. Decrease the amount of ham & cheese in your sandwich and replace it with lettuce and tomatoes - providing more nutrients.
What is lean body mass and what is its role in weight management?
The mass of your body that does not include fat. The more lean body mass you have the higher your BMR is.
When a cell requires or uses energy what metabolic reaction occurs to provide that energy to the cell?
The metabolism cycle
Why does fat provide more energy (kcal) per gram than carbohydrate, protein and alcohol?
The more C-H bonds in a nutrient, the more energy it can provide the body. Glucose yields 30 ATP. 16c fatty acid yields 129 ATP.
Describe the Set-Point Theory. Does this mean that no one can ever lose weight and keep it off?
The point at which controls are set. The body tends to maintain a certain weight by means of its own internal controls. No - the body's metabolism adjusts to restore the original weight so that what makes it more difficult to lose weight.
The heat generated in a bomb calorimeter for protein is 5.6 kcal/g, yet on a food label it tells me that protein is 4 kcal/gram. Why are these values different?
There are more factors ... CHECK PP
What nutrients are added to enriched grains?
Thiamin, niacin, riboflavin, iron
What is the significance of tryptophan in the diet in terms of niacin nutrition? If you ate a nice lunch of steak and eggs, which provided 300 mg of tryptophan, how many milligrams of niacin equivalents did this meal provide?
Trytophan can be used to make niacin. 300mg/60mg = 5 mg of niacin. 60mg of tryptophan = 1mg niacin produced
What are Sarah's and Sonia's BMI's? Would they be considered underweight, healthy weight, overweight or obese? List these cutoffs.
Underweight: <18.5 Healthy weight: 18.5-24.9 Overweight: 25-29.9 Obese: 30-39.9 Sarah (21.2) = healthy weight Sonia (29) = overweight
Ketosis
Undesirably high concentration of ketone bodies in blood & urine
What variables are accounted for in the DRI equation for calculating Total Energy Expenditure (this is called Estimated Energy Requirement in the text)? What variable that could contribute to a teenager's Total Energy Expenditure (TEE), is not accounted for in the TEE for adults? Note that a body builder laying down lean body mass would also not account for this variable.
Variables include gender, height, weight, age, and physical activity.
Sonia wants to lose weight and David has decided he wants to gain weight. Both have decided to throw caution to the wind and are going to get drugs from the black-market "they" say impact the regulation of food intake via known hormones and proteins. They have heard about leptin, neuropeptide Y, and cholecystokinin (CCK). From a purely speculative point of view, which of these might help each to either reduce or increase their appetite and food intake, as wished?
Weight loss: Leptin, CCK Weight gain: Neuropeptide Y
Under what conditions will the protein from a hamburger be converted to body fat? What about the carbohydrates in the diet; can they ever be converted to body fat? And now consider the fat in the diet; can it ever be converted to body fat?
Whatever is excess of protein and fats will be converted into body fat. Excess glucose will be stored as glycogen first and the excess will be converted to body fat.
When metabolizing a coca-cola drink (glucose), would it be converted to pyruvate before entering the TCA cycle?
Yes
16. Some cells in the body, e.g. brain cells, can adapt and use ketones for energy during starvation. This is the good news for survival. What is the bad news about ketone production?
You can produce too much ketones which leads to ketosis. Ketones are good for short term energy but not a good source for long term.
How would you explain the concept of internal regulation of eating and mindful eating to someone interested in losing weight with these principles?
You personally need to be aware of your own eating patterns and how you can lose weight in a healthy way.
A group of rats were fed a diet with inadequate amounts of all essential nutrients except niacin. They grew just as well as the control rats that were fed all nutrients including niacin. Niacin is still considered an essential nutrient for humans. Why? (Hint: think protein.)
triptophan can be used to make niacin.
