The answer to this question depends on your research question and other study-related factors. To learn more consider reading Chapter 4 (Nature of Variation in Diet) in the text Nutritional Epidemiology (third edition, 2013) by Walter Willett.
The answer to this question depends on your research question and other study-related factors. To learn more consider reading Chapter 4 (Nature of Variation in Diet) in the text Nutritional Epidemiology (third edition, 2013) by Walter Willett.