Can participants follow specific diets without needing to change or stop them, and do they need to maintain a stable condition throughout the study?

It's important for study participants to maintain stability throughout the study.

The specific requirements may vary depending on the study, but researchers generally want stable participants before, during, and after the study.

This means they prefer individuals who don't constantly change their diets when participating in a diet study, as it wouldn't be beneficial. 

For a liver study, for example, researchers wouldn't want someone who binge drinks occasionally. Consistency and stability are vital qualities that researchers look for in study participants.

The answer is provided by Karen Faulkner,

Senior Research Physician  at Synexus Clinical Research Ltd