The worldwide prevalence of obesity and overweight has risen substantially over the past three decades with no country yet achieving a reduction.1 International and national ambitions to “end childhood obesity”2 and “reduce non-communicable diseases by 25% by 2025”3 are unmatched by policiesthat could realise them. The causes of obesity are complex but overconsumption of food and sugary drinksis a critical proximal determinant, driven in part by large portion sizes. The importance of developing interventions and policies to reduce the size, availability, and appeal of large portionsis underscored by the compelling evidence that people eat and drink more from larger portions.