Most people eat more sugar than they consciously intend to. This isn’t primarily a failure of willpower. It’s a predictable outcome of food environments engineered by companies that have studied the behavioral economics of consumption carefully. These processes are documented, and knowing them is more useful than willpower advice.

Present Bias and Sugar Consumption

Behavioral economics distinguishes between stated preferences (what we say we want) and revealed preferences (what we actually choose). Most people state a preference for eating less sugar. Their revealed preference, measured by purchase and consumption data, shows they consistently choose sweetened options.

The gap reflects present bias. The tendency to heavily discount future consequences relative to immediate pleasure. A soda tastes good right now; the health consequences of regular soda drinking materialize over years. The brain weights the immediate experience far more than rational long-term calculation suggests it should.

Human temporal discounting is consistent, predictable, and well-documented — Kahneman, Thaler, and Sunstein built careers on it. Sugar companies exploit it deliberately.

Portion Size: The Wansink Effect

Before the replication crisis undercut some of his specific findings, Brian Wansink’s lab at Cornell documented consistent effects of portion size on consumption:

  • People eat more from larger containers regardless of their stated hunger
  • People pour more into wider glasses than narrow ones at equal volume
  • People eat significantly more popcorn from large vs. medium containers, even when the popcorn is stale
  • Bottomless soup bowls (secretly refilled by a tube) led subjects to eat 73% more than those with normal bowls

The underlying finding, that unit size and container size affect consumption independently of hunger, has been replicated by others and is consistent with large epidemiological patterns. Larger drink sizes, larger candy bars, and larger packages lead to more consumption.

The food industry has understood this for decades. McDonald’s introduced the concept of “supersizing”, offering substantially more food for a small price premium, because it dramatically increased calorie (and sugar) sales.

Anchoring and Serving Sizes

FDA serving sizes are meant to represent typical consumption but function as anchors, reference points that shape perception. When a candy bar lists a serving as one-quarter of the bar, the implicit message is “one-quarter is a reasonable amount.” Most people eat the whole bar.

Conversely, when serving sizes are anchored high, people feel licensed to consume more. A 2019 study by Hollands et al. found that larger default portion sizes increased consumption by 35% across studies, regardless of the product.

Default Options and Opt-Out Psychology

Default beverage in combos. When the default drink in a restaurant combo is soda rather than water, most people take soda. A study by Just & Wansink (2009) found that making water the default beverage in school cafeteria lunch combos reduced soda selection by 30% without any prohibition or change in prices.

Beverage suggestive selling. Fast food training protocols include upsell prompts: “Would you like to make that a large?” Studies of fast food receipts show upselling increases average beverage size and calorie intake.

Checkout aisle placement. Candy at point-of-sale checkout is explicitly designed to exploit impulse buying. A known behavioral vulnerability. In the UK, restrictions on checkout aisle candy in major supermarkets were associated with 17% reduction in impulse purchases of high-sugar snacks.

Sugar Taxes as Behavioral Interventions

The sugar-sweetened beverage tax in Berkeley, California (the first U.S. city tax, passed in 2014, 1 cent/oz) reduced SSB sales in low-income neighborhoods by 21% and increased water consumption by 63%, per a 2016 study by Falbe et al.

The Philadelphia beverage tax (1.5 cents/oz, 2017) increased water and diet beverage consumption by 35% and reduced SSB consumption by 38%, but increased cross-border shopping, reducing the net effect within city limits.

The behavioral mechanism: even small price changes shift relative attractiveness between sweetened and unsweetened options. Combined with labeling and placement interventions, these changes operate without prohibiting choice — the “libertarian paternalism” approach.

Marketing to Children

Children are not equipped with adult cognitive defenses against advertising. The food industry spends approximately $1.8 billion per year marketing to children in the U.S., with sugar-sweetened cereals, candy, fast food, and juice among the most heavily advertised categories.

FTC data shows children view approximately 13 food advertisements per day on television, over 80% for food categories that are high in sugar, fat, or sodium. Chile and Mexico have enacted marketing restrictions specifically targeting child-directed advertising of high-sugar products; a 2021 Lancet paper found Chile’s restrictions reduced children’s recognition of and preference for heavily marketed brands.

Explore Further

Sources

  • Thaler RH & Sunstein CR. Nudge. Penguin 2009, behavioral economics framework that underpins most food environment interventions
  • Falbe J et al. “Impact of the Berkeley Excise Tax on Sugar-Sweetened Beverage Consumption.” AJPH 2016
  • Hollands GJ et al. “Portion, package or tableware size for changing selection and consumption of food, alcohol and tobacco.” Cochrane Database 2015