A lot of our nutrition studies will ask you to be fasted overnight. In other words, avoiding all foods and drinks other than water. This is because we commonly want to measure compounds in the blood before a meal is consumed, such as fasting blood sugar or cholesterol. These are standard blood markers with well known healthy ranges we can compare to. These fasted samples could also be used as baseline reference to see how these markers change over time after eating.

Eating a meal, even a few bites, could change those blood markers, so it is best to be honest with your study team if you forgot to fast. Most studies will also encourage you to be well hydrated, especially if you will be providing a blood sample in the HNRU. The most important thing is that you are familiar with what the study team is asking of you and that you ask questions to them directly, if you are unsure. And remember it is always your right to withdraw from a study for any reason.