Registration Examination for Dietitians (RD/RDN Exam) — Questions and Answers

Question 1: What term describes the daily minimum amount of a nutrient needed to prevent deficiency in healthy individuals?

Estimated Average Requirement (EAR)
Adequate Intake (AI)
Tolerable Upper Intake Level (UL)
Recommended Dietary Allowance (RDA) (Correct answer)

Correct answer: Recommended Dietary Allowance (RDA)

The RDA is the daily intake level sufficient to meet the needs of nearly all healthy individuals in a specific group.

Question 2: What are essential amino acids?

Amino acids found only in plant foods
Amino acids the body can produce on its own
Amino acids that must be obtained through diet (Correct answer)
Amino acids used solely for energy production

Correct answer: Amino acids that must be obtained through diet

Essential amino acids cannot be synthesized by the body and must be consumed through food.

Question 3: Which of the following best describes how intermittent fasting affects muscle mass?

It has no effect on muscle mass
It always causes significant muscle loss
It increases muscle mass in all users
It can preserve muscle mass if protein intake and resistance training are adequate (Correct answer)

Correct answer: It can preserve muscle mass if protein intake and resistance training are adequate

With adequate protein intake and resistance exercise, intermittent fasting can preserve and even support muscle mass while reducing body fat.

Question 4: Which dietary strategy helps reduce hunger while maintaining a calorie deficit for weight loss?

High-volume, low-calorie foods (e.g., vegetables, lean protein) (Correct answer)
Eating only liquid meals
Eating one large meal per day
Avoiding all carbohydrates

Correct answer: High-volume, low-calorie foods (e.g., vegetables, lean protein)

Eating high-volume, low-calorie foods like vegetables and lean protein helps fill the stomach and signal satiety while keeping total calorie intake low.

Question 5: How many different phases does the South Beach Diet have?

2
4
3 (Correct answer)
1

Correct answer: 3

The South Beach Diet is structured into three distinct phases: Phase One (the most restrictive, for rapid weight loss), Phase Two (gradual weight loss and reintroduction of some foods), and Phase Three (maintenance for long-term healthy eating).

Question 6: Foods rich in carbs and starch are crucial because

They stop you from getting overweight
They are easy to cook
They give you energy and fill you up (Correct answer)
They help you grow

Correct answer: They give you energy and fill you up

Carbohydrates, including starches, are the body's primary source of energy. They are broken down into glucose, which fuels all bodily functions and physical activities. Consuming foods rich in carbs and starch also contributes to satiety, helping you feel full and satisfied after meals.

Question 7: Why are fruits and vegetables important?

They are colorful
They give you energy
They are easily available
They provide you with a wide variety of vitamins, minerals, and nutrients (Correct answer)

Correct answer: They provide you with a wide variety of vitamins, minerals, and nutrients

Fruits and vegetables are crucial because they are packed with a wide array of essential vitamins, minerals, and dietary fiber. These micronutrients support various bodily functions, including immune system health, vision, digestion, and protection against chronic diseases. Their diverse nutrient profiles are fundamental for maintaining overall well-being.

Question 8: Which macronutrient has the highest thermic effect of food (TEF), meaning the body burns the most calories digesting it?

Alcohol
Fat
Carbohydrates
Protein (Correct answer)

Correct answer: Protein

Protein has a TEF of approximately 20–35%, compared to 5–15% for carbohydrates and 0–3% for fat, making it the most metabolically costly macronutrient to digest.

Question 9: What is the primary fuel source for moderate-intensity aerobic exercise lasting longer than 20 minutes?

Fat (Correct answer)
Carbohydrates
Alcohol
Protein

Correct answer: Fat

After the first 20 minutes of moderate aerobic exercise, fat becomes the dominant fuel source as glycogen stores deplete.

Question 10: Which electrolyte is most commonly lost and must be supplemented on a ketogenic diet?

Zinc
Iron
Calcium
Sodium (Correct answer)

Correct answer: Sodium

Sodium is rapidly lost through increased urination as insulin levels drop on a ketogenic diet, making supplementation essential.

Question 11: Which South Beach Diet stage is the least constricting?

Second
First
Fourth
Third (Correct answer)

Correct answer: Third

Phase Three of the South Beach Diet is the maintenance phase, where individuals have achieved their goal weight and learned sustainable eating habits. It is the least restrictive phase, allowing for a wider variety of foods while still emphasizing healthy choices for long-term weight management.

Question 12: What macronutrient ratio is typical for a standard ketogenic diet?

60% fat, 20% protein, 20% carbs
50% fat, 30% protein, 20% carbs
40% fat, 40% protein, 20% carbs
70% fat, 25% protein, 5% carbs (Correct answer)

Correct answer: 70% fat, 25% protein, 5% carbs

A standard ketogenic diet typically consists of 70% fat, 25% protein, and only 5% carbohydrates to induce ketosis.

Question 13: True or false: When more people join a healthy lifestyle plan, weight loss becomes more difficult.

False (Correct answer)
True

Correct answer: False

Joining a healthy lifestyle plan with more people often provides a supportive community, increased motivation, and shared accountability, which can make weight loss easier and more sustainable. Social support is a recognized factor in successful health behavior change.

Question 14: Which cooking technique helps reduce phytates in legumes and improve mineral absorption?

Microwaving
Frying at high heat
Freezing
Soaking and sprouting (Correct answer)

Correct answer: Soaking and sprouting

Soaking, sprouting, and fermenting legumes and grains reduces their phytate content, improving the bioavailability of minerals like iron and zinc.

Question 15: A well-planned plant-based diet can be nutritionally complete for which life stages?

All life stages including infancy, childhood, pregnancy, and older adulthood (Correct answer)
Only for people under 50 without health conditions
Adults and elderly only
Adults only

Correct answer: All life stages including infancy, childhood, pregnancy, and older adulthood

Major dietetic associations, including the Academy of Nutrition and Dietetics, state that well-planned plant-based diets are nutritionally adequate for all stages of life.

Question 16: Which of the following is a high-fat, keto-friendly food?

Oatmeal
Brown rice
Olive oil (Correct answer)
Sweet potato

Correct answer: Olive oil

Olive oil is nearly 100% fat with zero carbohydrates, making it an ideal staple for a ketogenic diet.

Question 17: Which symptom is commonly associated with the initial transition to a ketogenic diet?

Iron deficiency anemia
Hyperthyroidism
Keto flu (Correct answer)
Hyperglycemia

Correct answer: Keto flu

The 'keto flu' is a common set of symptoms (fatigue, headache, irritability) experienced during the first days of starting a ketogenic diet.

Question 18: What does the term 'energy availability' mean in sports nutrition?

Calorie surplus needed for weight gain
Dietary energy remaining after subtracting exercise energy expenditure, relative to lean body mass (Correct answer)
The glycogen stored in muscles before exercise
The total calories consumed in a day

Correct answer: Dietary energy remaining after subtracting exercise energy expenditure, relative to lean body mass

Energy availability = (dietary intake − exercise energy cost) ÷ fat-free mass; low energy availability can impair hormonal and metabolic function.

Question 19: Which medical condition was the ketogenic diet originally developed to treat?

Epilepsy (Correct answer)
Type 2 diabetes
Obesity
Heart disease

Correct answer: Epilepsy

The ketogenic diet was developed in the 1920s as a treatment for epilepsy, particularly in children who didn't respond to medications.

Question 20: Which of the following sweeteners is generally considered keto-friendly?

High-fructose corn syrup
Table sugar
Stevia (Correct answer)
Honey

Correct answer: Stevia

Stevia is a zero-calorie, zero-carb natural sweetener that does not raise blood sugar and is considered keto-friendly.

Question 21: Which beverage is typically allowed during all phases of the South Beach Diet?

Regular soda
Fruit juice
Water and unsweetened coffee or tea (Correct answer)
Sweetened sports drinks

Correct answer: Water and unsweetened coffee or tea

Water and unsweetened beverages like coffee and tea are permitted throughout all phases, while sugary drinks are avoided.

Question 22: Which supplement has the strongest evidence for improving high-intensity exercise performance and is approved by major sports organizations?

Creatine monohydrate (Correct answer)
Glutamine
Collagen peptides
BCAAs alone

Correct answer: Creatine monohydrate

Creatine monohydrate is one of the most extensively studied and effective supplements for increasing power output and muscle mass during resistance and high-intensity training.

Question 23: Which type of carbohydrate is digested most slowly and helps regulate blood sugar?

High-fructose corn syrup
Simple sugars
Complex carbohydrates (Correct answer)
Refined grains

Correct answer: Complex carbohydrates

Complex carbohydrates contain long chains of glucose that digest slowly, providing sustained energy and stabilizing blood sugar.

Question 24: Post-exercise muscle protein synthesis is maximally stimulated by consuming approximately how many grams of high-quality protein?

20–40 g (Correct answer)
Over 100 g
5–10 g
60–80 g

Correct answer: 20–40 g

Studies show 20–40 g of leucine-rich protein effectively maximizes muscle protein synthesis; amounts above this offer diminishing returns per meal.

Question 25: Which of the following is a Phase 1 South Beach Diet-approved vegetable?

Carrots
Beets
Corn
Spinach (Correct answer)

Correct answer: Spinach

Spinach is a non-starchy, low-glycemic vegetable permitted freely in Phase 1, while corn, carrots, and beets are higher in sugar and restricted.

Question 26: How does intermittent fasting affect growth hormone (HGH) levels?

HGH increases significantly during fasting (Correct answer)
HGH levels are unaffected by fasting
HGH decreases during fasting
HGH is converted to insulin during fasting

Correct answer: HGH increases significantly during fasting

Fasting has been shown to significantly increase growth hormone levels, which supports fat burning and muscle preservation.

Question 27: A person on the South Beach Diet is dining at a restaurant. Which entrée choice best aligns with Phase 2 guidelines?

Fried shrimp with white rice
Cheeseburger on a brioche bun
Grilled chicken over mixed greens with olive oil dressing and a side of brown rice (Correct answer)
Pasta primavera with white pasta

Correct answer: Grilled chicken over mixed greens with olive oil dressing and a side of brown rice

Grilled chicken, mixed greens, olive oil dressing, and brown rice represent lean protein, healthy fats, non-starchy vegetables, and a low-glycemic whole grain — all Phase 2 compatible.

Question 28: Which mineral is most critical for oxygen transport in the blood and directly impacts exercise endurance?

Zinc
Magnesium
Iron (Correct answer)
Calcium

Correct answer: Iron

Iron is a core component of hemoglobin, which carries oxygen from the lungs to working muscles during aerobic exercise.

Question 29: What does the '5:2' intermittent fasting protocol involve?

5 meals on 2 days per week
Fasting 5 days and eating 2 days per week
Eating normally 5 days and restricting to ~500 calories on 2 non-consecutive days (Correct answer)
5 hours eating, 2 hours fasting daily

Correct answer: Eating normally 5 days and restricting to ~500 calories on 2 non-consecutive days

The 5:2 protocol involves eating normally for 5 days per week and significantly reducing calorie intake to around 500–600 calories on 2 non-consecutive days.

Question 30: What is the most common intermittent fasting protocol?

24-hour fast
5:2 method
Alternate day fasting
16:8 method (Correct answer)

Correct answer: 16:8 method

The 16:8 method — fasting for 16 hours and eating within an 8-hour window — is the most popular and widely practiced intermittent fasting protocol.

Question 31: The Physicians Committee for Responsible Medicine (PCRM) recommends a plant-based diet for what primary health benefit?

Improving eyesight
Increased athletic performance only
Building maximum muscle mass
Reducing the risk of heart disease, cancer, and type 2 diabetes (Correct answer)

Correct answer: Reducing the risk of heart disease, cancer, and type 2 diabetes

PCRM advocates plant-based diets primarily for their well-documented ability to reduce risks of heart disease, certain cancers, and type 2 diabetes.

Question 32: Which macronutrient has the highest thermic effect of food (TEF)?

Protein (Correct answer)
Carbohydrates
Fat
Alcohol

Correct answer: Protein

Protein has the highest thermic effect, requiring 20–30% of its caloric value just for digestion and metabolism.

Question 33: Which of the following snacks best fits South Beach Diet Phase 1 guidelines?

Celery with almond butter (Correct answer)
Crackers and cheese spread
A banana with honey
A handful of pretzels

Correct answer: Celery with almond butter

Celery (non-starchy vegetable) with almond butter (healthy fats and protein) is ideal for Phase 1, avoiding refined carbs and sugar.

Registration Examination for Dietitians (RD/RDN Exam)

The CDR Registration Examination for Dietitians assesses entry-level competency in nutrition care, dietetics principles, food and nutrition science, and management of food systems to credential Registered Dietitian Nutritionists.

Questions

40 min

Time Limit

70%

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