People eat meals rather than nutrients or food groups. Meals are typically eaten off of plates in American households. Plate size may influence meal size, meal composition, and food type. To examine the effects of plate size on meals, a new method called plate mapping was developed to analyze how participants responded to varying plate sizes and shapes. Four unique studies were developed and analyzed that used plate mapping to examine how various plates affected participant's estimations of food portion size and meal size. Two quasi-experimental studies asked participants to accurately draw and label a dinner on either a 9" or 11" standard paper plate. One quasi-experimental study asked participants to complete the same study design using either a 9.5" or 10.5" plate divided into three compartments. To validate plate mapping, a quasi-experimental study was conducted that asked participants in a college cafeteria to draw their self-purchased lunch at either pre-consumption or post-consumption time points on either a 9" or 11" paper plate. Three studies were done on the campus of a large college in the Northeastern United States (n=270, n=248, & n=98) and a fourth study recruited adults from a medium sized city in the Northeastern United States (n=281). The independent variable was plate size. Dependent variables were meal size, meal plate coverage, individual sizes of foods by food type and portion, and temporal condition of a meal (pre- or post-     consumption). Gender was a moderating variable. Overall, the size of plate drawings was highly correlated with the size of actual foods when the size of the plate drawn on was equivalent to the size of the plate containing the food. This provides support for the validity of the method of plate mapping and suggests that researchers must be cognizant of plate size whenever conducting research involving plates. Participants reported larger meal sizes whenever larger plates were provided, suggesting that participants are sensitive to the size of the plate and predict or recall meals as larger in the presence of larger plates. Gender moderated meal size drawings, with women generally drawing meals that were more highly correlated and similarly sized to actual meals than men. The effects from differing plate sizes appears to be more powerful for males than females and may encourage larger food servings by men. These findings suggest plate mapping can be used to reflect meal conceptualizations and assess sensitivity to plate size. Further research examining plate sizes influence on meals is needed to increase understanding of how participant estimations of "proper" meal sizes are developed and maintained.