Table 2 Studies into the effectiveness of interventions aimed at portion size

Antonuk, 2006 [43]

Package nutritional information; dual column labelling: not only nutritional information for one serving but also for the entire package

Random between subjects, parallel group design (nutritional information about serving size ('single column') vs nutritional information about serving size and entire package ('dual column')

College students, n = 112

-Non dieters ate significant less of a snack food when confronted with dual labelling

-No effect on intake of dieters

Harnack, 2008 [44]

Elimination of value size pricing and calorie labelling of different fast food portion sizes

Random 2(value pricing or normal pricing) × 2(calorie labelling or no labelling) between subjects design

Regular fast food restaurant visitors, adolescents and adults, n = 594

-No differences in energy composition of ordered meals

Lieux, 1992 [45]

Maximum of 1 hot entrée per person, no larger portions on request

Observational within subjects study, with four measurements

College students, n = 214

- Men increased selection of other foods so that energy intake remained the same

- Women chose the same foods

Rolls, 2006 [46]

25% Reduction in portion size and 25% reduction in energy density (i.e. by substituting full-fat ingredients by low-fat ingredients or by increasing the proportion of fruit & vegetables

Within subjects cross over design with four conditions

Young women, n = 24

-Independent effects of reducing portion size and energy density on energy intake found, effects sustained over 2 days

-Stronger effect of reduction in energy density

-No effect on ratings of hunger and fullness

Ueland, 2009 [47]

Portion size information; written descriptions with a comparison to a reference amount, i.e. " this is 1,5 times a normal portion of this pasta"

Within subjects crossover design

Normal weight adults, n = 33

-No effect on on total food intake

-No effect on satiety