Free practice final
Nutrition practice final (free, with answers)
An intro nutrition final typically covers the energy-yielding nutrients, digestion and absorption, vitamins and minerals, energy balance and body weight, the Dietary Reference Intakes, and nutrition at different stages of life. These 15 questions include the kcal and BMI calculations that often appear. Work each one out before opening the answer, then read the explanation to see why it is right.
For exam practice only, not personal diet or medical advice.
Topics
- Macronutrients and Energy
- Digestion and Absorption
- Carbohydrates
- Lipids
- Protein
- Vitamins and Minerals
- Energy Balance and Body Weight
- Dietary Reference Intakes
- Life Cycle Nutrition
15 questions
Try each one before you open its answer.
1. A cocktail contains 21 g of alcohol and 15 g of sugar, with no fat or protein. Using 7 kcal/g for alcohol and 4 kcal/g for carbohydrate, how many kcal does it provide?
- A 144 kcal
- B 147 kcal
- C 207 kcal
- D 249 kcal
Show answer
Answer: C. 207 kcal
Alcohol gives 21 g × 7 kcal/g = 147 kcal and sugar gives 15 g × 4 kcal/g = 60 kcal, for a total of 207 kcal. Alcohol supplies energy but no essential nutrients, which is why its kcal are often called empty calories.
2. A patient has had the terminal ileum surgically removed because of Crohn's disease. Absorption of which nutrient is most likely to be impaired?
- A Iron
- B Folate
- C Glucose
- D Vitamin B12
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Answer: D. Vitamin B12
The terminal ileum has the receptors that absorb vitamin B12 bound to intrinsic factor, and it also reabsorbs bile salts. Iron is absorbed mainly in the duodenum, and folate and most glucose in the duodenum and jejunum.
3. A granola bar contains 25 g of carbohydrate, 6 g of protein, and 9 g of fat. Using 4, 4, and 9 kcal/g, how many kcal does it provide, and what percentage of those kcal comes from fat?
Show answer
Answer: 205 kcal, about 40% of them from fat
Carbohydrate gives 25 × 4 = 100 kcal, protein 6 × 4 = 24 kcal, and fat 9 × 9 = 81 kcal, for 205 kcal in total. Fat's share is 81 ÷ 205 ≈ 0.395, or about 40%.
4. A person with low lactase activity drinks a large glass of milk and develops bloating, gas, and diarrhea. What causes these symptoms?
- A An immune reaction against milk proteins such as casein
- B Lactose is absorbed, but the liver cannot convert it to glucose
- C The fat in milk cannot be emulsified without lactase
- D Undigested lactose reaches the colon, where it draws in water and is fermented by bacteria into gas
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Answer: D. Undigested lactose reaches the colon, where it draws in water and is fermented by bacteria into gas
Without enough lactase, lactose is not split into glucose and galactose and cannot be absorbed, so it stays in the gut and pulls in water by osmosis. Colonic bacteria ferment it, producing gas and short-chain fatty acids. A milk allergy, by contrast, is an immune response to milk protein.
5. Which fatty acid is essential, meaning the body cannot make it and it must come from the diet?
- A Alpha-linolenic acid (an omega-3 fatty acid)
- B Oleic acid (an omega-9 fatty acid)
- C Palmitic acid
- D Stearic acid
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Answer: A. Alpha-linolenic acid (an omega-3 fatty acid)
Humans lack the enzymes to insert double bonds at the omega-3 and omega-6 positions, so alpha-linolenic acid and linoleic acid must come from food. Oleic, palmitic, and stearic acids can all be made in the body from other fats or from carbohydrate.
6. After a fatty meal, long-chain fatty acids absorbed by intestinal cells are rebuilt into triglycerides and packaged into which lipoprotein, which enters the lymph rather than the blood?
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Answer: Chylomicrons
Chylomicrons are too large to enter blood capillaries, so they pass into lacteals (lymphatic vessels) and reach the bloodstream through the thoracic duct. Short- and medium-chain fatty acids are more water-soluble and go directly into the portal blood instead.
7. Which person is most likely to be in positive nitrogen balance, taking in more nitrogen than they lose?
- A A patient in the first days after a severe burn
- B A healthy, growing 8-year-old child
- C An adult on prolonged bed rest
- D An adult who has been fasting for several days
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Answer: B. A healthy, growing 8-year-old child
Positive nitrogen balance means protein is being added to the body, as happens during growth, pregnancy, and the rebuilding of muscle. Fasting, immobility, and severe injury or illness cause net protein breakdown and a negative balance.
8. Grains are typically low in the essential amino acid lysine, and legumes are low in methionine. What term describes eating the two together, as in rice and beans, so that each supplies what the other lacks?
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Answer: Complementary proteins (protein complementation)
The essential amino acid in shortest supply relative to need is the limiting amino acid, and it caps how well a protein can be used to build body proteins. Combining foods with different limiting amino acids supplies a complete set, and the foods need not be eaten at the same meal as long as they are eaten over the course of the day.
9. A person with long-term heavy alcohol use and a poor diet develops confusion, an unsteady gait, and abnormal eye movements. Deficiency of which vitamin is the classic cause?
- A Vitamin C
- B Vitamin D
- C Thiamin (vitamin B1)
- D Vitamin A
Show answer
Answer: C. Thiamin (vitamin B1)
Confusion, ataxia, and abnormal eye movements are the classic signs of Wernicke encephalopathy, caused by thiamin deficiency. Thiamin is a coenzyme in carbohydrate metabolism, which the brain relies on for energy, and heavy alcohol use reduces both thiamin intake and absorption.
10. A vegetarian eats a meal of lentils and brown rice. Which addition would most increase absorption of the non-heme iron in the meal?
- A A cup of black tea
- B A glass of orange juice
- C A calcium supplement
- D A serving of wheat bran
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Answer: B. A glass of orange juice
Vitamin C reduces ferric iron (Fe³⁺) to the more soluble ferrous form (Fe²⁺) and keeps it in solution, increasing its absorption. Tannins in tea, calcium, and the phytates in bran all reduce non-heme iron absorption.
11. A person's usual daily intake of a nutrient is above the RDA but below the UL. What is the best interpretation?
- A The intake is very likely adequate, and the risk of adverse effects is low
- B The intake is likely deficient, because the RDA is the minimum needed to prevent disease
- C The intake is likely to cause toxicity, because any intake above the RDA is excessive
- D Nothing can be concluded, because DRIs apply only to groups, never to individuals
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Answer: A. The intake is very likely adequate, and the risk of adverse effects is low
The RDA is set high enough to meet the needs of about 97 to 98 percent of healthy people in a life-stage and sex group, so a usual intake above it has a low probability of being inadequate. The UL is the highest usual intake unlikely to cause adverse effects, so staying below it keeps that risk low.
12. When there is not enough evidence to determine an EAR for a nutrient, and therefore no RDA can be calculated, which DRI value is set instead?
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Answer: Adequate Intake (AI)
The AI is based on the intakes observed in apparently healthy people and is assumed to be adequate, but without an EAR the RDA, which is calculated from it, cannot be set. Dietary fiber, and every nutrient for infants up to 6 months old, are examples of values set as AIs.
13. For a typical sedentary adult, which component makes up the largest share of total daily energy expenditure?
- A Physical activity
- B Basal metabolism (the energy used at rest to keep the body running)
- C Thermic effect of food
- D Adaptive thermogenesis, such as heat produced in response to cold
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Answer: B. Basal metabolism (the energy used at rest to keep the body running)
Basal metabolism, the energy used to keep organs working, maintain body temperature, and sustain cell processes at rest, accounts for roughly 60 to 75 percent of daily energy use in a sedentary adult. Physical activity is the most variable component, and the thermic effect of food is only about 10 percent.
14. An adult is 1.70 m tall and weighs 81 kg. What is the BMI, and which category does it fall in? (Adult categories: 18.5 to 24.9 healthy weight, 25.0 to 29.9 overweight, 30.0 or more obesity.)
Show answer
Answer: About 28.0 kg/m², in the overweight range
BMI = weight in kg ÷ (height in m)² = 81 ÷ 1.70² = 81 ÷ 2.89 ≈ 28.0 kg/m², which falls between 25.0 and 29.9. BMI is a screening tool: it does not measure body fat directly or distinguish muscle from fat.
15. Why is adequate folate intake stressed for all women who could become pregnant, not only for those who already know they are pregnant?
- A Folate is needed mainly to mineralize the fetal skeleton late in pregnancy
- B Folate taken before pregnancy prevents gestational diabetes
- C The neural tube closes within about 4 weeks after conception, often before a pregnancy is recognized
- D Folate can no longer be absorbed once pregnancy begins
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Answer: C. The neural tube closes within about 4 weeks after conception, often before a pregnancy is recognized
Neural tube defects such as spina bifida arise when the neural tube fails to close, which happens very early, by roughly day 28 after conception. Because many pregnancies are not recognized that early, folate status needs to be adequate beforehand.