Quiz
Tap a question to see the answer
1. How many calories does a gram of protein, carbohydrate, fat and alcohol give?
About 4, 4, 9 and 7 (Figure 2; Fats, Water and Ethanol).
2. A tablespoon of olive oil has 14 g of fat. Why does the label say about 120 calories?
14 g × 9 kcal per gram is 126, and labels round calories above 50 to the nearest 10 (Figure 6).
3. Plain yogurt lists 11 g of total sugars but 0 g added sugars. Where does the sugar come from?
Lactose, the sugar naturally in milk (Figure 3; Carbohydrates, Figure 8).
4. What makes yogurt thick and tangy?
Cultures turn lactose into lactic acid, which sets the milk proteins into a gel and tastes sour (Figure 3; Processing, Figure 6).
5. Why is cholesterol a separate line in milligrams rather than part of Total Fat?
Cholesterol is a sterol built from four rings, not a triglyceride, and it has no calories (Lipids, Figure 3).
6. A can of beans lists 400 mg of sodium per serving. Roughly how much salt is that?
About 1 g, since salt is about 2.5 times the sodium figure (Figure 4; Major Minerals, Figure 8).
7. What is calcium chloride doing in canned beans?
It is a firming agent, an additive (E509) that keeps the beans from going soft (Figure 4; Additives).
8. Why can you eat canned kidney beans straight from the can but not raw or undercooked ones?
The canning heat destroys the lectins that cause illness (Figure 4; Antinutrients, Figure 6).
9. Why do beans and grains make a good protein pair?
Beans are rich in lysine but low in methionine, and grains are the reverse (Figure 4; Protein, Figure 7).
10. Starch and oat beta-glucan are both made of glucose. Why is one fiber?
Beta-glucan uses beta links that human enzymes cannot cut, while starch uses alpha links that amylase breaks (Figure 5; Carbohydrates, Figure 6).
11. Why are oats steamed before they are rolled?
To stop a fat-splitting enzyme that would make them go rancid (Figure 5; Processing).
12. What does “enriched” mean on flour, and which added vitamin helps prevent neural tube defects?
B vitamins and iron are added back after milling; folic acid prevents neural tube defects (Figure 7; Water-Soluble Vitamins).
13. Where do the holes in bread come from?
Yeast ferments sugar into carbon dioxide gas, which the gluten network traps; the ethanol bakes off (Figure 7; Water and Ethanol, Figure 5).
14. Why toast bread to golden rather than dark brown?
Browning forms acrylamide, and darker toast has more of it (Figure 7; Processing, Figure 3).
15. Which fat-soluble vitamin does olive oil supply, and what does it protect?
Vitamin E, alpha-tocopherol, which protects fats in the oil and in your cell membranes from oxidation (Figure 6; Fat-Soluble Vitamins, Figure 5).
16. Which two Non-Nutrients lessons cover compounds that never get their own label line?
Antinutrients and bioactives, such as phytate and polyphenols (Figures 1 and 2).
17. Does “0 g trans fat” guarantee there is none?
No. Less than 0.5 g per serving can be listed as 0 g (Figure 8).
18. On the % Daily Value column, what counts as low and what counts as high?
5% or less is low and 20% or more is high (Figure 2).