Efficacy and effectiveness, while related, differ significantly, especially in medical and nutritional interventions. Efficacy refers to the performance of an intervention under ideal and controlled circumstances, while effectiveness measures how well it performs in real-world settings.

and discuss this distinction in the context of nutritional strategies on the . They emphasize that while efficacy is important for understanding how treatments can work in perfect conditions, effectiveness is crucial because it takes into account real-world complexities like adherence to diets. They also discuss the value of efficacy in informing policies, such as decisions about food stamp allocations and public health guidance about nutrition. Ioannidis suggests using controlled trials and Mendelian Randomization studies to gain insights on efficacy, but also stresses the importance of interpreting observational data with caution 1.

Efficacy vs Effectiveness

John and Peter discuss the importance of separating efficacy from effectiveness when it comes to nutritional strategies. While effectiveness in real-world scenarios is crucial, understanding the optimal treatment under perfect circumstances is necessary for informing policy and changing the food environment. They explore different approaches to gaining insights on efficacy, such as controlled trials and Mendelian Randomization studies, emphasizing the need for cautious interpretation of observational evidence.

The Peter Attia Drive Podcast

#143 - John Ioannidis, M.D., D.Sc.: Why most biomedical research is flawed, and how to improve it