Dietary Nudging

The policy question of how governments move populations toward healthier eating. The evidence to date divides into two families:

1. Persuasion and mild nudges — campaigns, education, voluntary guidance, small-scale placement tweaks. Decades of these coincided with rising obesity: Britain adopted 689 anti-obesity policies between 1992 and 2020, only two carrying a financial disincentive, while England's obesity rate doubled. Colombia's adult obesity rose fivefold since 1980 to about a quarter of adults.
2. Food-environment re-engineering — mandatory warning labels, taxes on sugary drinks and ultra-processed foods, sales and placement restrictions, VAT redesign. These change what manufacturers and retailers do, not just what consumers are told.

What the stronger measures have shown

• Mexico, 2020 front-of-pack warning labels (Garduño-Alanis et al., Social Science & Medicine 2026, sales data 2017–2022): calories sold −15%, added sugar −25%, saturated fat −12%, sodium −7%, about 65 kcal per person per day. Roughly 90% of the calorie reduction came from manufacturers reformulating to avoid the label (co-author estimate) — the policy worked mainly on the supply side.
• Mexico sugary-drink tax: sales −6% in year one.
• Colombia, 2022: black warning labels plus a tax rising 10% → 15% (2024) → 20% (2025); outcome data not yet in.
• Modelling (Nesta): modest changes to a quarter of basket items could cut calories 8.5% and potentially halve obesity.

Where the measures leak

• Substitution: when Britain banned junk food at checkouts, exempt fresh pastries filled the shelf. Narrow rules invite workarounds; hence proposals for whole-basket healthiness targets on supermarket sales.
• Perverse tax structures: a Nature study found ten European countries charge higher VAT on fruit and vegetables than on meat and dairy.
• Measurement: the Mexican results are sales, not consumption or weight; no obesity outcome has yet been attributed to labels or taxes.

Related

• Nagging People to Eat Healthily Does Not Work (Economist) — source page.
• GLP-1s — the drug route the Economist piece sets aside as costly and indefinite.
• Food Fads — social-media-driven demand spikes that policy has to contend with.