the differences between people and in mention. but there are other issues too even with largest surveys often participants are required to give information about their eating habits or health stretching back over long periods of time but who can remember exactly what they ate months ago let alone years. more precise studies require participants to keep an up to date protocol of what they're eating the problem here is that it can be time consuming and the longer the study lasts the more the participants are likely to lose interest and give inaccurate responses. then there are those who tend to cheat there are unwilling to admit to the odd indulgence here in their. evaluation results is also a complex business such as happens often have very different. eating habits