Chapter 22 — Exercises

Three tiers. 🚪 marks threshold work; 🪞 reflection; 🔄 retrieval. ⚠️ This is Part IV's closing chapter — Tier 3 is deliberately retrospective.**

Tier 1 — Recall and Comprehension

R1. Give NOVA's four groups with two examples each. ⚠️ What is the classification tracking, if not nutrients?

R2. Name four features that mark a food as Group 4.

R3. 🚪 State the threshold concept. ⚠️ Give the three facts from §22.2 that break the "purity ladder" reading of NOVA.

R4. Describe the Hall ward trial design in full — population, setting, randomization, duration, what was matched, and how intake was measured.

R5. State the result: calories, weight change on each arm, and the mechanistic observation.

R6. ⚠️ Give the five limitations from §22.4. Which do you find most serious?

R7. List §22.5's seven mechanisms in order of evidential support. ⚠️ Which three are best supported, and what do they have in common?

R8. ⚠️ Give §22.7's six objections to NOVA. Which does the chapter call hardest to answer?

R9. What are §22.8's three replies? ⚠️ Which one does the ward trial supply directly?

R10. State §22.9's two-part answer to "what was Part IV about?"

R11. What does §22.11 say cooking from scratch actually requires? Give all seven.

R12. ⚠️ Give §22.12's five things not to conclude.

R13. What happened to the food supply in each of §22.2's four eras? ⚠️ What problem was each step solving?

Tier 2 — Application

A1. 🔄 Classify. Assign each to a NOVA group and justify:

a) Home-baked white bread b) Supermarket wholemeal bread with emulsifier c) Tinned baked beans in tomato sauce d) Plain full-fat yoghurt e) Fruit-flavoured yoghurt with thickeners f) Olive oil g) A cake you baked from flour, butter, sugar and eggs h) Infant formula i) Frozen peas j) A plant-based burger patty

⚠️ Which three did you find hardest, and what does that tell you about §22.7's first objection?

A2. 🚪 The threshold, tested. For each pair, say which the purity reading and which the threshold reading would prefer, and whether they disagree:

a) Tinned sardines vs. a "natural" protein bar b) Frozen broccoli vs. wilting fresh broccoli c) Homemade cake vs. a low-sugar packaged biscuit d) Pasteurized milk vs. raw milk

A3. The ward trial's counterfactual. Suppose the trial had found no difference in intake.

a) What would that have established? b) ⚠️ Which of Part IV's factions would that have helped, and how? c) Would the cohort associations still stand? What would you conclude from them?

A4. Explain the 500 calories. ⚠️ The diets were matched for presented calories, energy density, macronutrients, sugar, sodium and fiber.

a) Which of §22.5's mechanisms can still operate under that matching? b) Which are ruled out or weakened? c) ⚠️ Design the follow-up study that would isolate the one you think is responsible.

A5. The biscuit. Take the ingredients list from the chapter's hook.

a) Write the sentence each Part IV faction would say about it. b) ⚠️ Write the sentence this chapter says. c) Which sentence leads to the most durable change, and why?

A6. Design the shopping strategy for a household with $180/week, four people, one working two jobs, no freezer, and a 25-minute bus ride to the nearest large supermarket.

⚠️ You may not use the phrase "cook from scratch." Show your food list and your reasoning.

Tier 3 — Analysis and Synthesis

S1. 🔄 ⚠️ The Part IV answer, graded. Go and get what you wrote for Chapter 20 Exercise M5 and Chapter 21 Exercise S6.

a) How close were you to §22.9 part one? b) ⚠️ Did you get anywhere near part two — the conversion of a systemic problem into a purchase? c) If you didn't, what would have had to be different for you to see it? ⚠️ Be specific: was it missing information, or a framing you weren't looking for?

S2. ⚠️ Attack this chapter. §22.7 gives six objections; §22.8 replies to three.

a) Pick the objection you find strongest and write the best reply to §22.8. b) Construct the study that would show NOVA adds nothing beyond energy density and palatability. c) ⚠️ If that study came back positive, what should this chapter be rewritten to say? Write the replacement verdict.

S3. Reformulation. §22.10b argues nutrient rules get gamed and formulation categories don't.

a) ⚠️ Design a policy based on NOVA. What exactly does it regulate? b) What's the first thing manufacturers do in response? c) ⚠️ Does your policy survive that response? If not, revise it. If you can't, say so — §22.7's fourth objection may be fatal to policy even if the science holds.

S4. The equity problem. §22.11 says UPF is cheapest per calorie and cooking requires seven unequally-distributed resources.

a) ⚠️ Rank the seven by how hard they'd be to address at population scale. b) Which could policy change within five years? Give one concrete intervention for each. c) ⚠️ Is "eat less UPF" ethical advice to give someone for whom it is not achievable? Argue both, then say what you'd actually do in a consultation.

S5. ⚠️ The convergence argument, examined. §22.6 justifies 🟢 on convergence: trial + mechanism + cohorts.

a) Chapter 18 used the same structure to reach ✅ for SSBs. ⚠️ Compare the two convergences — which is stronger, and why? b) What's the failure mode of convergence reasoning? Construct a case where three methods agree and are all wrong for the same reason. c) ⚠️ Does that failure mode apply here?

S6. 🔄 The whole of Part IV. Using the closing table:

a) ⚠️ Thirteen entries sit in the 🟡/⚗️ column, on the questions people argue about most. Is that a defensible position for a textbook to take, or an evasion? b) The practical column contains almost nothing anyone argues about. ⚠️ What does that imply about the relationship between public argument and useful knowledge? c) Write the 100-word summary of Part IV you'd give someone who won't read it.

🪞 Reflection

M1. ⚠️ You made predictions in the Learning Check-In. How wrong were you, and in which direction? Did your three mechanisms involve ingredients or physics?

M2. §22.9 part two says every faction converted a systemic problem into a shopping decision, because a purchase is individually actionable. ⚠️ Have you done this? Not necessarily with food — name one systemic problem you have responded to by buying something.

M3. ⚠️ The chapter says the researcher behind its flagship trial has published work complicating his own finding. How did that affect your reading of the trial? Should it have?

M4. §22.12 warns this framing can become the thing Chapter 34 is about. ⚠️ Read the four questions from Chapter 21 §21.12 again and apply them to "avoiding UPF." Honestly.

M5. ⚠️ The one thing to remember is "twenty people, the same nutrients, and a 500-calorie difference. The food did it." Does that make you feel more or less in control of what you eat? Sit with whichever answer you got — Part V is about what you do next.