Chapter 7 — Exercises

Part C2 — sorting your own diary into intact and refined — is the one that changes behavior. Do that one even if you do nothing else.

Difficulty legend: ⭐ basic recall · ⭐⭐ applied · ⭐⭐⭐ synthesis and judgment · ⭐⭐⭐⭐ extension

Selected answers in Appendix J.

Part A — Conceptual Understanding ⭐

A1. Name the four structural categories of carbohydrate with an example of each.

A2. Why is "simple versus complex" described as a poor guide? Give two foods that break it.

A3. Define intact and refined, and list four ways they differ.

A4. What is glycemic index, how is it measured, and how does glycemic load differ from it?

A5. List the five problems with using GI as a personal food-selection system.

A6. What is resistant starch? Name two ways it arises, and state honestly how large the cooking-and-cooling effect is.

A7. Give the three layers of "how much carbohydrate do you need," with the number attached to each.

A8. What is a normal postprandial glucose response in a person without diabetes? What is the genuinely concerning pattern?

A9. Explain in two sentences how the low-fat era contributed to the low-carbohydrate era.

A10. What are phytates and lectins, and why does the outcome evidence override the mechanistic concern?

A11. Why do sugar alcohols cause digestive symptoms? Which one is best tolerated, and why?

A12. What is "net carbs," and what are the two problems with it?

Part B — Applied Analysis ⭐⭐

B1. For each pair, say which produces the slower glucose response and why: (a) white rice vs. brown rice; (b) apple vs. apple juice; (c) boiled potato vs. potato salad eaten cold; (d) instant oats vs. steel-cut oats; (e) white bread vs. sourdough.

B2. Calculate carbohydrate as a percentage of energy for: (a) 250 g carbohydrate in a 2,000 kcal diet; (b) 400 g in a 3,200 kcal diet; (c) 90 g in a 1,800 kcal diet. Which fall inside the 45–65% AMDR?

B3. A cereal box claims "made with whole grains." The panel shows 2 g fiber and 12 g added sugars per serving, and the ingredient list begins "enriched wheat flour, sugar, whole grain oat flour." Assess the claim using §7.12.

B4. Camila's colleague said white rice "is basically sugar" because it digests to glucose. The statement is chemically accurate. Explain in three sentences why the conclusion doesn't follow.

B5. Someone eats a bowl of ice cream and a boiled potato and finds the potato produces a higher glucose response. Explain the mechanism, and say what this reveals about using GI as a health hierarchy.

B6. A low-carbohydrate product lists 22 g total carbohydrate, 9 g fiber, 8 g maltitol, and claims "5 g net carbs." Identify the problem with this calculation.

B7. Using §7.6, give a defensible carbohydrate recommendation for each: a marathon runner in peak training; a sedentary 55-year-old with an HbA1c of 6.1%; a 4-year-old picky eater; a night-shift nurse eating her main meal at 3 a.m. Justify each in one sentence.

B8. Explain why the phytate/lectin argument is a Chapter 2 rung-conflict, naming the rungs on each side.

Part C — Skills & Practice ⭐⭐–⭐⭐⭐

C1. Do the carbohydrate audit. The Project Checkpoint: total, percentage of energy, intact/refined split, the liquid line, placement, and one swap with an honest likelihood rating.

C2. The intact/refined sort. Take every carbohydrate-containing food from your three-day diary and put each into one of two columns. Estimate the split. Most people find 70–85% refined. Record your actual number.

C3. The liquid-carbohydrate line. Total everything you drank that contained carbohydrate over three days — juice, soda, sweetened coffee, sports drinks, mixers. Convert to grams and calories per day. For many readers this single number is the chapter's most actionable output.

C4. The 300-calorie experiment. Over four separate occasions, eat 300 kcal of: whole fruit · fruit juice · steel-cut oats · a refined breakfast cereal. Record how long each took to eat and when you next felt hungry. Compare your data to §7.3's predictions.

C5. Read four labels. Pick four carbohydrate-containing packaged foods from your kitchen. For each, record: total carbohydrate · fiber · total sugars · added sugars · first three ingredients. Then rank them intact-to-refined and check whether the front-of-pack claims match your ranking.

C6. The rice question. Someone tells you to cut a staple food that is cheap, cultural, and eaten by a family member who is a fussy eater. Write the response you'd actually give — under 150 words, honest about the evidence, and not condescending to either the person or the person who gave the advice.

C7. Price the alternatives. In an actual shop, price per pound: dried lentils · brown rice · rolled oats · white flour · almond flour · a "grain-free" bread. Calculate the cost of feeding four people a starch component from each. Then reconsider who the carbohydrate-avoidance advice is written for.

Part D — Synthesis & Critical Thinking ⭐⭐⭐

D1. The chapter argues that both very-high-carbohydrate and very-low-carbohydrate traditional populations show low metabolic disease, and that this tells you less than either camp claims. Construct the strongest argument that it does tell you something actionable. Then say whether it survives.

D2. GI is described as a good research tool and a poor everyday system. Is there a category of person for whom it's genuinely the right everyday tool? Define that category precisely.

D3. The RDA for carbohydrate is 130 g/day, and there is no essential carbohydrate. Explain how both can be true, then argue about whether the RDA is useful or misleading as a public communication.

D4. The chapter says the low-carb era "succeeds, where it succeeds, largely because of what gets replaced." A low-carbohydrate advocate objects: this is unfalsifiable — you're attributing any success to something other than the mechanism I propose. Is the objection fair? What evidence would distinguish the two explanations?

D5. Consider the class dimension in the 🧾 cost check. If the foods most often demonized are the cheapest, and the replacements the most expensive, what obligations does that place on people giving public nutrition advice? Does it change what you're entitled to say confidently?

Part M — Mixed & Interleaved Practice ⭐⭐–⭐⭐⭐

M1. (With Chapter 3.) Explain the intact/refined distinction entirely in terms of Chapter 3's mechanisms — enzyme access, gastric emptying, satiety hormones, and colonic fermentation. Use no term from this chapter.

M2. (With Chapter 6.) Someone eats 400 g of carbohydrate daily and asks whether the excess is "turning into fat." Using Chapter 6, explain what actually happens to carbohydrate in surplus, and which Chapter 4 concept determines the answer.

M3. (With Chapter 2.) Run the whole grain evidence through the Claim Filter. Which questions does it answer well? Which does it answer poorly? Does it deserve more confidence than most nutrition claims?

M4. (With Chapters 2 and 5.) The erythritol study got a 🟡 verdict. Name the specific Chapter 2 problems that drove that verdict, and say what study design would resolve it.

M5. (With Chapters 4 and 5.) A person cuts carbohydrate and loses 6 lb in five days. Using Chapter 4 §4.9 and Chapter 6 §6.2, explain what that weight is and predict what happens when carbohydrate returns.

M6. (With Chapter 3.) Nico's stomach aches were attributed to gluten. Using §7.11, name an alternative carbohydrate-based explanation and say what the family should have done before eliminating anything.

M7. (Revisit at Chapter 18.) Write down now what you think the honest verdict on sugar will be. Seal it.

Part E — Research & Extension ⭐⭐⭐⭐

E1. Find the original glycemic index work by Jenkins and colleagues from the early 1980s. What problem were they trying to solve, and what did they claim for it? Compare that to how GI is marketed now. This is a good study in a research tool escaping its intended use.

E2. Read the Weizmann Institute work on personalized glycemic responses (Zeevi, Segal, and colleagues). How large was the between-person variation? What did they use to predict it? Then read at least one critique, and consider what would have to be true for this to become clinically useful. (Chapter 35 revisits it.)

E3. Investigate the whole grain literature. Find a recent systematic review or meta-analysis. How strong is the dose-response? How do the authors handle healthy-user bias? Then find the strongest published critique of the whole grain consensus and evaluate it.

E4. Read the 2023 Nature Medicine erythritol paper and at least two responses to it. Identify precisely where the disagreement sits — is it about the data, the confounding, the endogenous production, or the mechanistic experiments? Write a paragraph on what would settle it.

E5. Investigate the resistant starch literature. How much does cooling actually increase RS in rice, potato, and pasta, and what is the measured effect on glucose response and energy availability? Compare the published figures to how the finding is presented online.