CDN Nutritional Science & Dietetics 3 — Questions and Answers
Question 1: During prolonged fasting, which metabolic state predominates to spare muscle protein?
- Glycolysis
- Ketosis (Correct answer)
- Gluconeogenesis from amino acids only
- Lipogenesis
Correct answer: Ketosis
Ketosis allows the brain and other tissues to use ketone bodies as an alternative fuel, reducing the need to catabolize muscle protein for gluconeogenesis.
Question 2: Which vitamin functions as a coenzyme in transamination reactions involving amino acid metabolism?
- Thiamine (B1)
- Riboflavin (B2)
- Pyridoxine (B6) (Correct answer)
- Niacin (B3)
Correct answer: Pyridoxine (B6)
Pyridoxal phosphate (PLP), the active form of vitamin B6, is the coenzyme required by aminotransferases (transaminases) that transfer amino groups between molecules.
Question 3: A Registered Dietitian Nutritionist calculates a patient's protein needs at 1.5 g/kg/day. The patient weighs 176 lbs. How many grams of protein are required daily?
- 80 g
- 100 g
- 120 g (Correct answer)
- 132 g
Correct answer: 120 g
176 lbs ÷ 2.2 = 80 kg; 80 kg × 1.5 g/kg = 120 g of protein per day.
Question 4: Which mineral is a structural component of thyroid hormones T3 and T4?
- Selenium
- Fluoride
- Iodine (Correct answer)
- Chromium
Correct answer: Iodine
Iodine is directly incorporated into the thyroid hormones triiodothyronine (T3) and thyroxine (T4), which regulate metabolic rate.
Question 5: The glycemic index (GI) of a food is most directly affected by which factor?
- Total calorie content
- Fat content
- Starch structure and fiber content (Correct answer)
- Protein content
Correct answer: Starch structure and fiber content
The ratio of amylose to amylopectin and the amount and type of dietary fiber primarily determine how rapidly a food raises blood glucose, thus affecting GI.
Question 6: Which assessment method most accurately measures total body fat percentage in a clinical setting?
- BMI calculation
- Skinfold calipers (3-site)
- Dual-energy X-ray absorptiometry (DXA) (Correct answer)
- Bioelectrical impedance analysis (BIA)
Correct answer: Dual-energy X-ray absorptiometry (DXA)
DXA is considered the gold standard for body composition assessment in clinical settings because it directly measures fat mass, lean mass, and bone mineral density.
Question 7: A food label lists 0 g trans fat per serving, but the ingredients include 'partially hydrogenated oil.' What does this indicate?
- The food is completely free of trans fat
- The product may contain up to 0.5 g trans fat per serving due to FDA rounding rules (Correct answer)
- Partially hydrogenated oil does not produce trans fat
- The label is in error and the manufacturer must be reported
Correct answer: The product may contain up to 0.5 g trans fat per serving due to FDA rounding rules
FDA labeling rules allow rounding to 0 g if trans fat content is less than 0.5 g per serving, so foods containing partially hydrogenated oils may still have small amounts.
CDN Nutritional Science & Dietetics 3
During prolonged fasting, which metabolic state predominates to spare muscle protein?