Shape up! How shape, size and addition of condiments influence eating behavior towards vegetables

Practical approaches to increase consumption of healthy foods such as vegetables are needed. Controlling eating rate is a promising strategy, since faster eating rates have been related to higher food intake. Food properties can be modified to influence eating rates, but little is known about the impact of vegetable dimensions and condiment additions on eating rates of vegetables. This study determined the influence of shape, size and condiment properties on eating behavior towards carrots. Eating behavior (mastication time, number of chews, chewing frequency, eating rate) was determined for carrots with same total weight but different shapes (cube, julienne), and varying in size, number of pieces and aspect ratio. Carrots presented in one large cube required the lowest mastication effort (shortest mastication time, fewest chews) among all pre-cut carrots. Carrot cubes required less mastication effort leading to higher eating rates than carrots julienne. To investigate the effect of condiment addition on eating behavior towards carrots, mayonnaises varying in fat content and viscosity were combined with carrots, and mastication behavior and bolus properties were determined. Mayonnaises, in particular those with high fat content or low viscosity, contributed to faster bolus formation of carrots. Carrots were swallowed with less particles of larger sizes when mayonnaises were added. These results indicate that a specific particle size is not a prerequisite to induce swallowing, and that other bolus properties such as lubrication or cohesiveness trigger the urge to swallow. We conclude that eating behavior towards carrots can be controlled by relatively small changes in both carrot and condiment properties. To increase carrot intake by increasing eating rate, we suggest to avoid cutting of carrots or to add condiments, which could be an effective strategy to increase vegetable consumption or to decrease mastication effort to target the elderly population.