Texture-Based Differences in Eating Rate Reduce the Impact of Increased Energy Density and Large Portions on Meal Size in Adults

Background: Large portions and high dietary energy density promote overconsumption at meal times. This could be reduced by eating slowly.Objective: Two studies investigated whether texture-based reductions in eating rate and oral processing moderate consumption at breakfast in combination with variations in energy density and portion size.Methods: Adults attended 4 breakfast sessions (2 × 2 repeated-measures design) to consume rice porridge, combining a 45% reduction in eating rate [thin porridge (140 g/min) compared with thick porridge (77 g/min)] with a 77% increase in energy density (0.57 compared with 1.01 kcal/g) in study 1 [n = 61; aged 21-48 y; body mass index (BMI; in kg/m²): 16-29] and a 50% increase in portion size (100% compared with 150%) in study 2 (n = 53; aged 21-42 y; BMI: 16-29). Oral processing behaviors were coded by using webcams. Porridge intake was measured alongside changes in rated appetite.Results: Increases in energy density and portion size led to increases of 80% and 13% in energy intake at breakfast, respectively (P < 0.001), but only portion size increased the weight of food consumed (13%). The thicker porridges were consumed at a slower rate and led to 11-13% reductions in food weight and energy intake compared with the thin versions (P < 0.001). Combined, the least energy was consumed when the thick "slow" porridge was served with a lower energy density or smaller portion (P < 0.05). Although intake was reduced for the thick porridges, they were expected to be more filling than the thin versions and experienced as equally satiating postconsumption.Conclusions: Adults eat in response to external features of the food environment. An opportunity exists to use a combination of energy-density dilution, smaller portions, and natural variations in food texture to design meals that promote reductions in energy intake while maintaining satiety.