Macronutrients and Energy Requirements — MCQs
What does the glycemic index of a starchy food measure?
Which of the following is false regarding management of diabetes in pregnancy?
Which of the following protein sources has the lowest biological value?
Which cooking oil is known to have the highest percentage of polyunsaturated fatty acids?
Increased BMR is associated with -
Essential amino acids are named so because they:
Which of the following is most strongly associated with heart disease?
Which of the following has the lowest Respiratory Quotient (RQ)?
A 25 year old woman is a sedentary worker. She is a lactating mother with a 3 month old child. Which one among the following is the best approximation of her energy requirement in terms of kilocalories per day ?
What is the recommended additional energy requirement during the second and third trimesters of pregnancy?
Macronutrients and Energy Requirements Indian Medical PG Practice Questions and MCQs
Question 1: What does the glycemic index of a starchy food measure?
- A. The caloric content of the food
- B. The blood glucose response to carbohydrates (Correct Answer)
- C. The nutritional value of the food
- D. The fiber content of the food
Explanation: ***The blood glucose response to carbohydrates*** - The **glycemic index (GI)** specifically quantifies how quickly and how much a food's **carbohydrates** raise **blood glucose levels** after consumption. - Foods with a high GI are rapidly digested and absorbed, causing a **sharp rise in blood sugar**, while low GI foods lead to a more gradual increase. - GI is measured by comparing the blood glucose response to 50g of carbohydrate from the test food versus 50g of glucose or white bread as a reference standard. *The caloric content of the food* - **Caloric content** measures the energy provided by a food, expressed in **kilocalories (kcal)** or **Joules**. - While important for overall energy balance, it does not directly reflect the rate or magnitude of **blood sugar elevation**. - Two foods with identical caloric content can have vastly different glycemic indices. *The nutritional value of the food* - **Nutritional value** encompasses a broad range of components including **vitamins, minerals, fiber, protein, and fats**, in addition to carbohydrates. - The GI focuses solely on the **carbohydrate impact** on blood glucose and does not provide a comprehensive assessment of a food's overall nutritional benefits. *The fiber content of the food* - **Fiber content** is a separate nutritional measurement expressed in grams per serving. - While high fiber content can **lower** the glycemic index of a food by slowing carbohydrate digestion, the GI itself does not directly measure fiber. - Fiber is an important nutritional component but represents a distinct parameter from glycemic response.
Question 2: Which of the following is false regarding management of diabetes in pregnancy?
- A. In active labor, if RBS <70 mg/dL, D5 is started at 100-150 ml/hr till the RBS is >70 mg/dL
- B. In a patient being planned for induction of labor, night dose of intermediate insulin is given as planned, and the morning dose is withheld
- C. Elective C-section has no role in reducing incidence of brachial plexus injury (Correct Answer)
- D. Capillary blood glucose monitoring levels are kept at fasting- 95 mg/dL; 1 hr postprandial- 140 mg/dL; 2 hrs postprandial- 120 mg/dL
Explanation: ***Elective C-section has no role in reducing incidence of brachial plexus injury*** - This statement is **false** because **elective C-section** can significantly reduce the incidence of **brachial plexus injury** (BPI), especially in cases of suspected fetal macrosomia. - While not universally recommended for all diabetic pregnancies, an elective C-section is considered when the estimated **fetal weight** is substantial or when there's a history of **shoulder dystocia** to prevent birth trauma. *In active labor, if RBS <70 mg/dL, D5 is started at 100-150 ml/hr till the RBS is >70 mg/dL* - This is a **correct** management strategy for **hypoglycemia in labor**. Maintaining stable blood glucose levels (above 70 mg/dL) is crucial to prevent adverse outcomes for both mother and fetus. - The administration of **D5 (dextrose 5% in water)** intravenous solution at a specific rate helps to quickly raise and maintain blood glucose levels. *In a patient being planned for induction of labor, night dose of intermediate insulin is given as planned, and the morning dose is withheld* - This is a common and generally **correct** practice for insulin management before **induction of labor**. The night dose of intermediate insulin helps maintain basal glucose levels overnight. - Withholding the morning dose prevents **hypoglycemia** during labor when food intake is restricted, and insulin sensitivity may increase. Glucose is then typically supplemented through IV fluids as needed. *Capillary blood glucose monitoring levels are kept at fasting- 95 mg/dL; 1 hr postprandial- 140 mg/dL; 2 hrs postprandial- 120 mg/dL* - These are the generally accepted and **correct** target blood glucose levels for **diabetes in pregnancy** (both pre-existing and gestational diabetes). - Achieving these targets is essential to minimize the risk of **fetal macrosomia**, **neonatal hypoglycemia**, and other adverse perinatal outcomes.
Question 3: Which of the following protein sources has the lowest biological value?
- A. Gelatin (Correct Answer)
- B. Albumin
- C. Cashewnut protein
- D. Lactalbumin
Explanation: ***Gelatin*** - Gelatin is derived from collagen and is notably deficient in several **essential amino acids**, particularly **tryptophan**. - Its incomplete amino acid profile gives it a very **low biological value**, meaning it's poorly utilized by the body for protein synthesis. *Lactalbumin* - Lactalbumin is a **whey protein** found in milk, known for its **high biological value**. - It contains a **complete profile of essential amino acids** and is easily digestible. *Albumin* - Albumin, typically referring to **egg albumin** (egg white protein) or **serum albumin**, has an **excellent biological value**. - It is often used as a reference protein due to its well-balanced and **complete amino acid composition**. *Cashewnut protein* - While nuts like cashews provide protein, they generally have a **moderate to high biological value**, though typically not as high as animal proteins. - Cashew protein contains a good range of amino acids but might be slightly limited in one or two essential amino acids compared to a reference like egg or whey.
Question 4: Which cooking oil is known to have the highest percentage of polyunsaturated fatty acids?
- A. Safflower oil (Correct Answer)
- B. Coconut oil
- C. Butter
- D. Vanaspati
Explanation: ***Safflower oil*** - Safflower oil contains one of the **highest concentrations of polyunsaturated fatty acids**, particularly **linoleic acid**, among commonly used cooking oils. - This composition makes it a popular choice for health-conscious consumers looking to increase their intake of beneficial fats. *Coconut oil* - Coconut oil is predominantly composed of **saturated fatty acids**, notably **lauric acid**, which makes it solid at room temperature. - Its high saturated fat content distinguishes it significantly from oils rich in polyunsaturated fats. *Butter* - Butter is a dairy product that is very high in **saturated animal fats** and **cholesterol**. - Its fatty acid profile is dominated by short- and medium-chain saturated fatty acids, making it distinct from oils rich in polyunsaturated fats. *Vanaspati* - Vanaspati is a **partially hydrogenated vegetable oil** that is high in **trans fatty acids** and saturated fats due to its processing. - While it originates from vegetable oils, hydrogenation alters its fatty acid structure, reducing polyunsaturated content and increasing less healthy fats.
Question 5: Increased BMR is associated with -
- A. Increased body fat store
- B. Increased glycolysis (Correct Answer)
- C. Increased lipogenesis
- D. Increased gluconeogenesis
Explanation: ***Increased glycolysis*** - An increased **basal metabolic rate (BMR)** signifies higher energy expenditure at rest, which reflects increased cellular metabolic activity and ATP consumption. - Among the given options, **increased glycolysis** is most consistent with increased BMR, as glycolysis is the primary pathway for ATP generation from glucose, and cells with higher metabolic rates require increased energy production. - Conditions that increase BMR (such as hyperthyroidism, fever, and increased muscle mass) are typically accompanied by **increased glycolytic activity** to meet higher energy demands. *Incorrect: Increased body fat store* - **Increased body fat** is generally associated with a *lower* BMR per unit of body weight, as adipose tissue is metabolically less active than lean tissue (especially muscle). - Higher body fat percentage reflects **energy storage**, not increased energy expenditure, and does not contribute to elevated BMR. *Incorrect: Increased lipogenesis* - **Lipogenesis** (synthesis of fatty acids and triglycerides) is an anabolic process that occurs during states of **energy surplus** for fat storage. - This process represents energy **storage** rather than energy **expenditure**, and is inversely related to BMR - it increases when energy intake exceeds expenditure. *Incorrect: Increased gluconeogenesis* - **Gluconeogenesis** (synthesis of glucose from non-carbohydrate sources) is primarily active during **fasting, starvation, or prolonged exercise** when glucose availability is low. - While gluconeogenesis is energy-consuming, it is characteristic of catabolic states with low energy availability, not the increased metabolic activity associated with elevated BMR. - In conditions that increase BMR (like hyperthyroidism), glucose is typically utilized via glycolysis rather than synthesized via gluconeogenesis.
Question 6: Essential amino acids are named so because they:
- A. They are not important for life
- B. Not all food sources contain them
- C. Because they are not produced in the body (Correct Answer)
- D. Because they are required in large quantities
Explanation: ***Because they are not produced in the body*** - **Essential amino acids** are those that the body cannot synthesize on its own or cannot synthesize in sufficient quantities. - Therefore, they **must be obtained through diet** to meet the body's needs for protein synthesis and other metabolic functions. *They are not important for life* - This statement is incorrect; essential amino acids are **crucial for life** and various bodily functions. - They are the building blocks of **proteins**, which are vital for enzyme production, hormone synthesis, tissue repair, and many other biological processes. *Not all food sources contain them* - While it's true that not all food sources contain a complete profile of essential amino acids, this is **not the reason they are named "essential."** - Some plant-based foods may be lacking in one or more essential amino acids, requiring a varied diet to ensure adequate intake. *Because they are required in large quantities* - The quantity required is not the defining characteristic of an **essential amino acid**. - While some amino acids might be needed in larger amounts than others, their "essential" status refers to the **body's inability to synthesize them**, not their dietary quantity.
Question 7: Which of the following is most strongly associated with heart disease?
- A. HDL
- B. LDL (Correct Answer)
- C. VLDL
- D. Chylomicrons
Explanation: ***LDL*** - **Low-density lipoprotein (LDL)** is often referred to as "bad cholesterol" because high levels contribute to the buildup of **plaque** in the arteries, leading to **atherosclerosis** and increasing the risk of heart disease. - **Elevated LDL** promotes cholesterol deposition in arterial walls, narrowing the vessels and impeding blood flow. *HDL* - **High-density lipoprotein (HDL)** is known as "good cholesterol" as it helps remove cholesterol from the arteries and transport it back to the liver for excretion. - **High HDL levels** are generally protective against heart disease, not associated with its development. *VLDL* - **Very-low-density lipoprotein (VLDL)** primarily transports **triglycerides** synthesized in the liver to various tissues. - While high VLDL levels can increase the risk of heart disease, primarily due to their breakdown into LDL, **LDL itself is a more direct and stronger predictor** of atherosclerotic disease. *Chylomicrons* - **Chylomicrons** are responsible for transporting **dietary fats** (triglycerides and cholesterol) from the intestines to the rest of the body after a meal. - Although high levels of chylomicrons can be associated with increased triglyceride levels, they are typically present for only a few hours after eating and are **not as strongly implicated in chronic atherosclerosis** as LDL.
Question 8: Which of the following has the lowest Respiratory Quotient (RQ)?
- A. Heart
- B. Brain
- C. RBC
- D. Adipose (Correct Answer)
Explanation: ***Adipose*** - **Adipose tissue** primarily metabolizes **fatty acids** for energy, which have the lowest theoretical RQ of approximately **0.7**. - A lower RQ indicates that less carbon dioxide is produced relative to the oxygen consumed during metabolic fuel oxidation. - Among tissues that perform aerobic respiration, adipose tissue has the lowest RQ. *Brain* - The brain primarily uses **glucose** as its energy source under normal conditions, which has an RQ of approximately **1.0**. - During prolonged fasting, the brain can adapt to use **ketone bodies** (RQ ≈ 0.89), but glucose remains the primary fuel. - Higher RQ than adipose tissue. *RBC* - **Red blood cells (RBCs)** lack mitochondria and rely exclusively on **anaerobic glycolysis** for energy, metabolizing glucose to lactate. - RBCs **do not consume oxygen** for energy metabolism and therefore **do not have a meaningful RQ value** (RQ = CO₂ produced / O₂ consumed in aerobic respiration). - This makes RBC an inappropriate answer to a question about "lowest RQ" since RQ is undefined for anaerobic metabolism. *Heart* - The heart is a highly metabolic organ that can utilize various substrates, including **fatty acids**, **glucose**, **lactate**, and **ketone bodies**. - While it has a high capacity for fatty acid oxidation, it also significantly uses glucose and lactate, leading to an overall RQ typically between **0.7-0.9**. - Higher average RQ than adipose tissue due to mixed substrate utilization.
Question 9: A 25 year old woman is a sedentary worker. She is a lactating mother with a 3 month old child. Which one among the following is the best approximation of her energy requirement in terms of kilocalories per day ?
- A. 2500 kcal/d (Correct Answer)
- B. 1500 kcal/d
- C. 2250 kcal/d
- D. 2830 kcal/d
Explanation: ***2500 kcal/d*** - A lactating woman generally requires an additional 500 kcal/day above her baseline energy needs to support milk production. - For a sedentary woman, a typical baseline intake is around 2000 kcal/day, making 2500 kcal/day a good approximation during lactation. *1500 kcal/d* - This value is significantly low for a lactating woman, as it would likely lead to a **caloric deficit** and could compromise milk supply and maternal health. - This energy level might be appropriate for a woman on a **weight-loss diet**, but not for supporting lactation. *2250 kcal/d* - While closer than 1500 kcal/d, this value still falls slightly short of the recommended additional energy intake for lactation, which is typically an extra 500 kcal/day. - This might represent a moderate activity level for a non-lactating woman, but not optimal for **milk production**. *2830 kcal/d* - This amount would be more appropriate for a lactating woman with a **higher activity level** or a greater baseline energy requirement than a sedentary individual. - While some lactating women may need this much, it is likely an **overestimation** for a sedentary worker.
Question 10: What is the recommended additional energy requirement during the second and third trimesters of pregnancy?
- A. +600 kcal
- B. +350 kcal (Correct Answer)
- C. +520 kcal
- D. +300 kcal
Explanation: ***+350 kcal*** - The **recommended additional energy intake** during pregnancy is approximately **350 kcal/day** in the second and third trimesters. - This represents an average: **~340 kcal/day** in the second trimester and **~452 kcal/day** in the third trimester. - This increased intake supports **fetal growth, placental development, and maternal metabolic changes**. - Guidelines from WHO and IOM support this recommendation for healthy singleton pregnancies. *+600 kcal* - An additional **600 kcal/day** is significantly higher than the standard recommendation for healthy pregnant women. - Such a substantial increase might be appropriate only in cases of **multiple gestations, severe malnutrition, or high physical activity levels**. *+520 kcal* - This value is higher than the generally accepted average requirement for a typical singleton pregnancy. - While individual needs can vary, **520 kcal/day** is not the widely adopted guideline for average pregnancy requirements. *+300 kcal* - While often cited as a rough estimate, current guidelines recommend a slightly higher average of **340-350 kcal/day** for the second and third trimesters. - **300 kcal/day** may be considered on the lower end and is below the optimal recommendation.
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