The Sweetest Thing

Latif Nasser begins his investigation after his children ask what the sweetest thing is following hearing U2's "The Sweetest Thing." He consults with biochemist Eric Walters, who maintains a ranked list of sweeteners based on their potency relative to sugar. The list includes honey (1.5x sweeter), aspartame (200x), catempe fruit (2,000x), adventame (20,000x), and lugdenum (300,000x). However, when Latif tests adventame with his children, it tastes unpleasant rather than overwhelmingly sweet, revealing a critical distinction between potency and perceived sweetness intensity. Psychologist Linda Bartoszek explains that scientists measure potency—the smallest amount needed to trigger the sweetness receptor—not actual taste perception. Paul Breslin from Rutgers University introduces the dimmer switch metaphor: our sweetness perception reaches a plateau beyond which additional sweetener doesn't increase perceived sweetness. By this measure, sugar itself may be the sweetest thing, as it achieved the highest perceived intensity in evolution's design. Bartoszek then explains that fruits enhance sweetness perception not by adding more sugar but through volatile compounds that create smell signals, which overlap with taste signals to boost perceived sweetness. She demonstrates this by adding strawberry extract and red food coloring to honey, which significantly increases its perceived sweetness. Additional research shows that color vision (red-colored items taste sweeter) and high-pitched sounds can each increase sweetness perception by 5-10%, though the mechanisms remain unclear. Latif then visits Columbia University neurobiologist Charles Zucca, who discovered the sweetness receptor and has mapped the neural pathway from taste receptors through various brain regions to the cortex where sweetness is perceived. Zucca demonstrates his research using genetically modified mice with light-sensitive sweetness neurons, showing that stimulating these neurons with a laser makes the brain perceive sweetness regardless of actual taste input. This raises the possibility of creating an artificial sweetness experience that transcends any natural substance. Finally, Latif learns that astronomers recently discovered erythrolose, a complex sugar, in interstellar dust clouds near the Milky Way's center—the same sugar found in raspberries—suggesting that sweetness may exist as raw material throughout space in forms yet unknown to us.