Discussion Guava is one of the most popular fruits eaten in Thailand. It has been postulated as a very healthy fruit since it contains concentrated vitamin C(13). The present data revealed that guava also contained the highest total dietary fiber (2.40%) and a rather high phytate content (0.08%). These were due to the higher cellulose and uronic acid content(14) in this fruit more than the other 5 fruits. It is advisable that for colon cancer, ischemic heart disease and diabetes, patients should eat more guava. On the other hand, longan had the lowest total dietary fiber (0.19%) and the lowest phytate (0.037%) content and it is anticipated to cause higher glycemic response and may be unhealthy. It is surprising to see that ripe mango had a rather high phytate (0.086%) and a low dietary content. It is anticipated that ripe mango should have a high glycemic index. Dragon fruit also contained rather high dietary fiber (ranked 2nd) but it had a very low phytate content with durian and pineapple being in the middle. The relationship between the total dietary fiber, phytate content and glycemic effect of these fruits is needed in order to improve dietary counseling efficiency.