Due to the increasing risk of obesity and cardiovascular diseases caused by high-fat diets, low-fat foods have become a priority demand for consumers’ health. However, the smoothness perception and scientific assessment methods of the existing low-fat foods should be improved. In this study, three food emulsions were prepared, and their lubrication characteristics, sensory evaluation of smoothness, and electroencephalogram (EEG) signals were assessed to preliminarily investigate the effects of food emulsion components on their above characteristics. The results showed that fat substitute (FSU) and fat could significantly reduce coefficient of friction (CoF) of the food emulsions, with average CoF reduced by 28% and 63% compared to the original food emulsions. In addition, fat-enriched food emulsions continued to exhibit excellent lubrication characteristics after adding artificial saliva, with an average CoF reduced by 31.1% compared to that of the food emulsions without artificial saliva. Both FSU and fat improved the smoothness of food emulsions, and the lubricating properties of fat were more pronounced, with fat-enriched food emulsion which could provide a substantial improvement in smoothness compared to the fat-free food emulsion. Comparison of subjects’ EEG signals revealed that food emulsion with lower CoF and higher smoothness triggered higher P3 amplitudes and longer latencies. These findings provide better insights into the scientific evaluation of food texture and the development of low-fat foods.