Download Ans: disagree (triglyceride)

CHAPTER 3 ANSWERS TO STUDY QUESTIONS
1.
Create a “real world” food pyramid based upon the following actual average daily serving
consumption patterns. Actual consumption: fats, oils, and sweets = 3.2; milk, yogurt, and
cheese = 2.3; meat, poultry, fish, dry beans, eggs and nuts = 2.8; vegetables = 2.4; fruits = 2.3;
bread, cereal, rice, and pasta = 2.7. Compare to the USDA Food Guide Pyramid - what can
you conclude?
Ans: This pyramid would be top-heavy (too many sweets and fats); OK on milk, yogurt,
cheese; OK on meat, etc; low in terms of vegetables; Ok for fruit; and low in bread, cereal,
rice, and pasta.
2.
Explain the relationships between food protein biological value, nitrogen excretion, essential
amino acids, and protein synthesis.
Ans: Biological value refers to the protein quality of a food. It is given on a scale up to a
value of 100, which is for egg protein. Essential amino acids are those that the body needs to
obtain from foods – the nonessential ones it can manufacture itself. Protein synthesis refers
to an action hat takes place in cells when all of the essential amino acids are present
simultaneously in sufficient amounts. Foods containing high biological value protein supply
the essential amino acids required for protein synthesis, and the nitrogen (N) from them is
incorporated into new tissue and enzymes, etc. A healthy situation exists when a person has
an excess of body nitrogen (greater intake compared to N losses via excretion) = positive N
balance.
3.
Estimate the caloric value of a manufactured health food item containing 0.5 grams of
linolenic acid, 25 grams of fructose, 15 milligrams of vitamin C, 3 grams of fish liver oil, 11
grams of corn syrup, and 2.5 grams of polyarginine (a polypeptide made up of repeating units
of the amino acid arginine).
Ans: Calories would be derived from linoleic acid (0.5 grams x 9 kcal/g) + fructose (25 grams
x 4 kcal/g) + fish oil (3 grams x 9 kcal/g) + corn syrup (11 grams x 4 kcal/g) + polyarginine
(2.5 grams x 4 kcal/g) = 185.5 kcal
Vitamin C does not provide any calories.
4.
Agree or disagree with the following statements, justifying your answer.
(a) The most abundant lipid in the typical diet is cholesterol.
Ans: disagree (triglyceride)
(b) The lipoprotein responsible for reverse cholesterol transport (away from body cells) is VLDL.
Ans: disagree (HDL performs this function)
(c) The Food Guide Pyramid suggests 3 to 6 servings per day from fruits.
Ans: disagree (2-4 servings)
(d) The substance that emulsifies fat when it enters the small intestine is called intestinal lipase.
Ans: disagree (bile)
(e) A deficiency of energy or nutrients is correctly called malnutrition.
Ans: agree
(f) The current recommendation calls for no more than 30% of kcals to come from fat in the diet.
For a person consuming 2000 kcals per day, this would be 67 grams of fat.
Ans: agree (67 fat grams = 603 kcal = 30% of 2,000 kcal)
5. Protein is one nutrient for which an RDA (Recommended Dietary Allowance) can be
calculated. As an example of estimating the protein RDA, consider a five-foot four-inch 20-year
old female, with an actual weight of 145 pounds but a desirable body weight of 125 pounds.
Calculate her protein RDA, according to the following steps:
a.
b.
c.
Convert the recommended weight from pounds to kilograms by dividing by 2.2 (since one
kilogram is equivalent to 2.2 pounds).
Select the RDA factor of 0.8 grams of protein per kilogram of body weight for females of this
age group (for males, the factor would be 0.9).
Multiply this factor times the recommended weight for this individual to obtain the RDA for
protein.
Ans: From the data, 125/2.2 = 56.8 kg; 56.8 kg x 0.8 g protein/kg = 45.4 g protein per day for
the RDA.
6 – 22. Multiple Choice
6. b.
7. a.
8. e.
9. d.
10. c.
11. c.
12. a.
13. c.
14. e.
15. c.
16. a.
17. b.
18. b.
19. d.
20. e.
21. b.
22. e.