Atherosclerotic cardiovascular disease remains the leading cause of death for adults in the United States. The cardiovascular impact of milk consumption remains a matter of long-standing scientific debate. Current guidelines for Americans recommend three daily servings of fat-free or low-fat (1%) dairy over full-fat options due to concerns that saturated fat may increase cardiovascular risk. Yet, the literature does not consistently support non-fat dairy as superior to high-fat dairy for reducing cardiometabolic risk. Identifying the comparative health benefits of non-fat versus high-fat dairy milk would be immediately applicable to patients who seek cardiovascular care. In this randomized, case-crossover trial, the investigators seek to efficiently assess the association between high-fat versus non-fat dairy milk consumption and insulin resistance. Utilizing the Eureka Platform, participants will be randomized to limit their liquid milk consumption to whole milk followed by skim milk (or vice versa), measuring the effect of milk fat content on glycemic index and lipid profile.
The study is designed as an N of 1 randomized trial, where each participant will be randomized to consume high-fat versus non-fat dairy milk then crossover to the alternate condition over two consecutive two-month periods. After two and four months, participants will have lab tests performed, including hemoglobin A1c (HbA1c) and fasting lipids. Throughout the study, participants will be instructed to continuously wear a wrist-worn fitness tracker, use a Bluetooth-enabled scale and blood pressure monitor to trend weight and blood pressure weekly, and utilize the Eureka mobile application for self-monitoring of dairy milk consumption, diet, lifestyle, and physical activity. Aside from study-related dairy milk instructions, all other aspects of diet will remain constant throughout study participation. The study seeks to elucidate the relationship between dairy milk consumption and overall health. A total of 100 participants will be enrolled for participation in this clinical trial.