RD exam prep and study guide: domains, traps, 2027

Cauliflower cooked in a kitchen with hard, alkaline tap water comes out creamy yellow instead of white. Which change will best keep it white?

Choose a letter. The key opens with a short note under each of the choices.

1. ACooking in an uncoated cast-iron potCheck

   Iron from an uncoated pot reacts with anthoxanthins to form dark complexes, so it discolors the cauliflower instead of whitening it.
2. BAdding a little lemon juice to the waterCheck

   Cauliflower's white anthoxanthin pigments stay white in acid, so a little lemon juice offsets the alkaline water.
3. CCovering the pot tightly during cookingCheck

   Covering the pot traps only the small amount of volatile acid the vegetable releases, far too little to counter hard, alkaline tap water.
4. DAdding a pinch of baking soda to the waterCheck

   Baking soda makes the water even more alkaline, which deepens the yellow of anthoxanthins and softens the florets.

A cook doubles the sugar in a baked custard recipe without changing anything else. How will this most likely affect the custard?

1. AIt will curdle at a lower temperatureCheck

   Because sugar delays coagulation, curdling takes more heat, not less; extra sugar makes a custard harder to curdle.
2. BIt will set at a lower temperatureCheck

   Setting at a lower temperature reverses the effect: sugar raises the coagulation point of egg proteins rather than lowering it.
3. CIt will not set without added starchCheck

   Egg proteins form the custard gel on their own; extra sugar slows the set but does not prevent it, so starch is not needed.
4. DIt will set at a higher temperatureCheck

   Sugar surrounds egg proteins and delays their unfolding and bonding, so more sugar raises the temperature at which the custard sets.

A dietitian compares raw tomatoes with long-simmered tomato sauce. Which statement best describes the change in their nutrients?

1. AVitamin C falls, while lycopene becomes more bioavailableCheck

   Vitamin C is heat-labile and lost during long cooking, while heat breaks cell walls and frees lycopene, so more of it is absorbed.
2. BVitamin C and lycopene both decrease substantiallyCheck

   Lycopene is heat-stable and is released, not destroyed, by simmering; only the vitamin C half of this option holds.
3. CLycopene decreases, while vitamin C is concentratedCheck

   Lycopene does not decrease and vitamin C is not concentrated: the vitamin is destroyed faster than water evaporates, and lycopene becomes easier to absorb.
4. DBoth become more bioavailable as the cell walls break downCheck

   Breaking cell walls helps lycopene, but vitamin C is lost to heat and oxidation, so it cannot become more available.

A 3-year-old who was recently adopted internationally has a height-for-age z-score of −2.4 and a BMI-for-age z-score of −0.3. Which interpretation is most accurate?

1. ANormal growth; BMI is normalCheck

   A normal BMI-for-age does not cancel a height-for-age below −2; the child is short for age even though weight fits height.
2. BStunting (chronic)Check

   A height-for-age z-score below −2 marks stunting, the result of long-term undernutrition that has slowed linear growth.
3. CWasting (acute)Check

   Wasting, the acute form, shows as a low weight-for-height or BMI-for-age z-score, and this child's BMI-for-age of −0.3 is normal.
4. DOverweight relative to heightCheck

   A BMI-for-age z-score of −0.3 sits near the median, far below the +2 cutoff used for overweight in young children.

A 67-year-old in the ICU is receiving mechanical ventilation and has a BMI of 32. Indirect calorimetry is unavailable. Which predictive equation is most appropriate for estimating energy needs?

1. APenn State 2003bCheck

   Penn State 2003b is meant for ventilated adults under 60 and for older adults with a BMI below 30, not for an obese 67-year-old.
2. BPenn State 2010Check

   The modified Penn State 2010 equation was validated for ventilated patients aged 60 or older with a BMI of 30 or more, which fits this patient.
3. CMifflin-St JeorCheck

   Mifflin-St Jeor was derived from healthy adults and has no term for ventilation or temperature, so it is inaccurate in critical illness.
4. DHarris-Benedict × 1.3Check

   Harris-Benedict with a stress factor is an outdated method with poor accuracy in the ICU and a tendency to overfeed.

A dietitian plans to use a 24-hour urine urea nitrogen (UUN) collection to calculate nitrogen balance. For which patient would the result be most misleading?

1. AContinuous enteral feeding at goal rateCheck

   Continuous feeding at a known rate makes nitrogen intake easy to measure, which helps the calculation rather than spoiling it.
2. BHip fracture repair 5 days agoCheck

   Postoperative catabolism raises nitrogen losses, but the urine captures them, so the result stays meaningful after hip surgery.
3. CAcute kidney injury with a rising BUNCheck

   With acute kidney injury, urea builds up in the blood instead of reaching the urine, so UUN underestimates losses and the balance looks falsely positive.
4. DPneumonia with an elevated CRPCheck

   Inflammation from pneumonia speeds protein breakdown and urea output; the collection still measures that loss accurately.

A manager drops a $30 steak entrée with a 45% food cost and adds a $12 pasta entrée with a 20% food cost, expecting profit to rise. What is the main flaw in this decision?

1. AMiscalculating the food cost percentsCheck

   The percents are right ($13.50 of $30 and $2.40 of $12); the mistake is judging the items by percentage instead of dollars.
2. BIgnoring the labor cost of each dishCheck

   Labor matters for full costing, but the lost profit here comes from the smaller dollar margin left after food cost.
3. CTreating food cost as a fixed costCheck

   Nothing in the decision treats food cost as fixed; it still varies with each portion sold, and the flaw lies in comparing percentages.
4. DIgnoring dollar contribution marginCheck

   Contribution margin in dollars is what was ignored: the steak leaves $16.50 after food cost and the pasta $9.60, so each swapped sale loses $6.90.

A manager projected a $100 profit on 100 servings of a $12.00 limited-time entrée, using a food cost of $7.00 per serving and $400 in direct labor. The entire $7.00 is the as-purchased cost of a single ingredient, and that ingredient has an 80% edible yield. What is the true net contribution?

1. A−$75Check

   Edible-portion cost is $7.00 ÷ 0.80 = $8.75, so 100 servings cost $875 in food; $1,200 − $875 − $400 = −$75.
2. B+$325Check

   +$325 corrects the food cost for yield but leaves out the $400 of direct labor.
3. C−$40Check

   Multiplying $7.00 by 1.20 gives $8.40, which understates the cost; a yield is corrected by dividing by 0.80.
4. D+$100Check

   +$100 is the manager's original projection, which treated the as-purchased price as if every ounce were edible.

A long-term care facility serves its substantial evening meal at 5:00 PM. It does not offer a nourishing bedtime snack. By what time must breakfast be served under CMS requirements?

1. A9:00 AMCheck

   A 16-hour span to 9:00 AM is allowed only when a nourishing bedtime snack is served and a resident group agrees, and neither is true here.
2. B5:00 AMCheck

   Breakfast at 5:00 AM applies a 12-hour limit the rule does not set and falls well before normal community mealtimes.
3. C8:00 AMCheck

   Breakfast at 8:00 AM leaves a 15-hour gap, one hour more than allowed when no bedtime snack is offered.
4. D7:00 AMCheck

   Without a nourishing bedtime snack, CMS allows at most 14 hours between a substantial evening meal and breakfast, and 5:00 PM plus 14 hours is 7:00 AM.

A 40-gallon steam-jacketed kettle is filled to 80% of capacity with soup. How many 8-oz (1-cup) portions will it yield?

1. A640Check

   640 counts all 40 gallons and ignores that the kettle is only 80% full.
2. B128Check

   128 uses 4 units per gallon, which counts quarts instead of cups.
3. C512Check

   Eighty percent of 40 gallons is 32 gallons, and at 16 cups per gallon that is 512 one-cup portions.
4. D256Check

   256 uses 8 units per gallon, which counts pints rather than 8-oz cups.

A delivery arrives with a different brand of breaded chicken patty than the one named in the hospital's purchase specification, which allows an equal product that meets all of its stated requirements. What should the receiving clerk do?

1. AAccept it as a routine prime-vendor substitutionCheck

   A prime-vendor agreement does not waive the specification; a substitute still has to meet it before anyone signs for it.
2. BAccept it and let the cook decide whether it can be usedCheck

   Handing the call to the cook moves quality control out of receiving, after the product is already accepted and invoiced.
3. CCheck the label against the specification before acceptingCheck

   Receiving compares each item with the specification: a patty that meets every stated requirement is an acceptable equal, and one that falls short is refused.
4. DReject it automatically and reorder the specified brandCheck

   Rejecting it automatically may turn away an acceptable patty and leave the menu short, because the specification allows equal products.

A soup recipe is being increased from 50 to 500 portions. Which ingredient most needs a taste test before the full conversion factor is applied?

1. AGround cayenne pepperCheck

   Strong spices such as cayenne do not scale in a straight line, so they are raised cautiously and adjusted by tasting the large batch.
2. BLow-sodium chicken stockCheck

   Stock is a bulk liquid that scales directly with the conversion factor.
3. CCooked long-grain riceCheck

   Cooked rice is a bulk ingredient that is multiplied by the factor without special tasting.
4. DDiced yellow onionsCheck

   Diced onions add body and a mild flavor and scale directly; multiplied tenfold they do not overpower a soup.