UPSC Prelims 2011 Q62: Science & Technology – Health & Diseases
- (a) Aspartame is as sweet as table sugar, but unlike table sugar, it is not readily oxidized in human body due to lack of requisite enzymes
- (b) When aspartame is used in food processing, the sweet taste remains, but it becomes resistant to oxidation
- (c) Aspartame is as sweet as sugar, but after ingestion into the body, it is converted into metabolites that yield no calories
- (d) Aspartame is several times sweeter than table sugar, hence food items made with small quantities of aspartame yield fewer calories on oxidation
Answer: (d) Aspartame is several times sweeter than table sugar, hence food items made with small quantities of aspartame yield fewer calories on oxidation
Explanation
Why aspartame works as a low-calorie sweetener
Aspartame is chemically an amino-acid-based compound, which would normally yield calories like any protein, yet it's marketed as low-calorie.
| Option | Verdict | Reason |
|---|---|---|
| (a) Not readily oxidized due to lack of enzymes | Incorrect | This is not the real mechanism; aspartame is fully metabolized in the body |
| (b) Becomes resistant to oxidation after processing | Incorrect | There's no such resistance mechanism described for aspartame |
| (c) Converted into metabolites yielding no calories | Incorrect | Aspartame IS metabolized into its constituent amino acids, which do yield calories, contradicting this claim |
| (d) Far sweeter than sugar, so tiny amounts suffice | Correct | Aspartame is about 200 times sweeter than table sugar, so only a minuscule quantity is needed for the same sweetness, making the total calories from that tiny amount negligible |
Why aspartame is 'low-calorie' despite yielding calories per gram:
| Point | Detail |
|---|---|
| Sweetness | ~200x sweeter than sucrose |
| Quantity needed | Tiny amounts, so total calorie contribution is negligible |
| Per-gram calories | Same as other amino acids — it's the quantity, not the chemistry, that matters |
Answer: (d) Aspartame is several times sweeter than table sugar, hence food items made with small quantities of aspartame yield fewer calories on oxidation.
Why each option is right or wrong
- (a) Incorrect. Aspartame is readily metabolized by normal enzymes; the low-calorie effect is about quantity, not enzyme deficiency.
- (b) Incorrect. There is no oxidation-resistance mechanism involved; aspartame breaks down normally in digestion.
- (c) Incorrect. Aspartame's metabolites (amino acids) do yield calories; the claim of 'no calories' is false.
- (d) CORRECT. Because aspartame is far sweeter than sugar, only a tiny amount is used, so the total calories contributed are negligible.
Key point
Aspartame is low-calorie not because it avoids metabolism, but because it is ~200x sweeter than sugar — tiny quantities suffice, so total calorie contribution is negligible.
Remember
Aspartame: ~200x sweeter than sugar, so tiny amounts used yield negligible calories — not because it skips metabolism.
Common mistakes
- Assuming aspartame avoids normal digestion/oxidation altogether.
- Confusing 'no calories' claims with the real mechanism of small quantity, high sweetness.
- Not connecting sweetness intensity to the practical calorie math of food formulation.
Exam tip
Aspartame's 'low-calorie' trick is quantity, not chemistry: ~200x sweeter means 200x less needed, so fewer total calories per serving.
Sources
- Food Safety and Standards (Food Products Standards and Food Additives) Regulations, 2011 (artificial sweeteners)
- Joint FAO/WHO Expert Committee on Food Additives — Evaluation of Certain Food Additives: aspartame (WHO Technical Report Series)