The Reduced Calorie Food and Mood Study

Reformulation strategies to reduce the energy density of commonly consumed food and beverage products are needed to support weight management, but one concern is that awareness of consuming 'healthier' foods can promote compensatory eating behaviours. An alternative solution is not to label calorie-reductions so consumers are unaware that they are consuming fewer calories in reformulated products, which has been described as a 'stealth health' approach.

This study investigated whether consuming a reduced-calorie product labelled with Singapore's 'Healthier Choice Symbol' impacts its satiating power relative to an unlabelled control, and the extent to which this can be further modified by changes to the product's sensory characteristics.

Participants were randomised to consume an original (211 kcal per portion; kcal/g) and reduced calorie (98 kcal per portion; kcal/g) versions of a soymilk, with the reduced calorie version presented in one of four beverage context conditions:

• Context 1 - Sensory-matched, unlabelled calorie reduction (control) - Sensory matched to taste like the original (equally sweet, thick and creamy), without a label identifier (covert energy reduction).
• Context 2 - Sensory-matched, labelled calorie reduction - The same sensory matched beverage as above, but with the HCS attached (explicit energy reduction).
• Context 3 - Sensory-reduced, labelled calorie reduction - Designed to taste less thick, sweet and creamy than the original, with the HCS attached (explicit energy reduction).
• Context 4 - Sensory-enhanced, labelled calorie reduction - Designed to taste thicker, creamier and sweeter than the original, with the HCS attached (explicit energy reduction).

Participants consumed the two beverages (original vs. reduced energy) in one of the four beverage contexts on two non-consecutive test sessions at the Clinical Nutrition Research Centre, with at least three days washout between each session. The calorie reduction was conducted as full-crossover while the beverage context groups were assigned non-crossover, to reduce demand awareness.

The primary objective was to assess changes in lunch energy intake (kcal) after consuming the original and reduced-calorie beverages, depending on the beverage context the reduced calorie version was presented in.

The secondary objectives were to assess the sensory evaluations of the beverages (liking and perceived thickness, sweetness and expected fullness etc.), changes in rated appetite up to 180 minutes post-consumption and energy intake (kcal) for the rest of the test day (recorded in a food diary), as a function of the beverages energy density and context.