Kevin Klatt, PhD, RD

A well-designed/performed, double-blind, randomized, placebo-controlled trial provides a high level of certainty about the effectiveness of an intervention. In scientific training, the need to utilize a placebo relative to your variable of interest is one of the first things you learn when designing an experiment. As many in the basic sciences and evidence-based medicine fields have become more interested in nutrition and its impact on health/biology (their interest is well-justified), there has been insufficient appreciation for the difficulty in performing nutrition research. This day 1 principle of "placebo-controlled" poses a particular challenge for many nutrition experiments: there is no placebo.  Consider an example that actually plagued causal inference in nutrition history: It was known that feeding diets high in saturated fatty acids was associated with higher LDL. Does that mean that saturated fat raises LDL? How would you design a study to show