11 Gastric myoelectric activity while viewing and eating food in obese participants

Abstract

Purpose: This study observed the reactions of the stomach to food viewing and food eating in obese people.Method: The participants were 20 obese (mean BMI of 32) and 20 normal‐weighted (mean BMI of 21) undergraduate students, who were required to fast for at least 4 hours preceding the experiment. They viewed a video clip of food for 6 minutes; consumed food till full; and viewed the same video clip of food 30 minutes after the meal. Cutaneous electrogastrograms (EGGs) were recorded during the entire procedure. Questionnaires concerning the participants’ perception of somatic and affective changes during the tasks were completed.Results: The percentages of bradygastric, normal and tachygastric EGG activity were very similar between obese group and normal‐weighted group during the baseline period. During the first food image viewing, an increase in normal 3 cpm activity and a decreased in bradygastric activity occurred in both groups, but obese participants showed less of an increase in 3 cpm activity than normal‐weighted participants and the percentage of bradygastric activity was higher in obese group than in the normal‐weighted group. During the 30 min. period following the meal, a higher percentage of bradygastric activity and a lower percentage of 3 cpm activity were observed in obese participants than in normal‐weighted participants. Furthermore, obese participants showed a different pattern of change in 3 cpm and bradygastric activity than normal‐weighed participants during the 30 min. The whole 30‐min period was divided into five 6‐min periods. In the obese group, the percentage of 3 cpm activity decreased in the third and forth 6‐min periods and increased to the highest level in the last 6‐min period, while in the normal‐weighted group, the 3 cpm percentage was the greatest in the first 6‐min period. Obese participants and normal‐weighted participants reacted similarly to the second food image exposure, except that a higher increase in 3 cpm activity was observed in the normal‐weighted group in the period after the termination of viewing the food images.Conclusions: These data suggest that obese people react to food images and to food eating differently from normal‐weighted people. EGG activity in obese participants needs further investigation.