4. Discussion
cancer, eating behavior, weight loss, prediabetes
CANCER, CARDIOVASCULAR DISEASE, PREDIABETES
In this 16-week study of adults with overweight/obesity and prediabetes spanning the COVID-19 pandemic, we demonstrated that the addition of carbohydrate-last food order counseling to standard nutrition counseling improved nutrient intake, notably increasing the intake of protein and vegetables, although reductions in body weight and HbA1c were not significantly different from those observed with standard nutrition counseling alone. Participants reported high intervention adherence and likelihood of continuing to eat protein/vegetables before concentrated carbohydrates at meals, suggesting carbohydrate-last food order is a feasible behavioral strategy.Consuming a substantial quantity of fruits and vegetables is foundational to a healthy diet and has been shown to reduce the risk of cardiovascular disease, cancer, and all-cause mortality [Contrary to our postulated hypothesis, we did not observe significant differences between the study groups in glucose tolerance and HbA1c. This was not entirely unexpected given the unprecedented disruptions of the COVID-19 pandemic. No changes to physical activity were observed in either study group, supporting the objective to isolate the effects of the study intervention. Improvements in glucose tolerance have previously been described in more intensive lifestyle intervention programs that included moderate to vigorous intensity exercise [Given previous investigations of the carbohydrate-last food order intervention demonstrate perturbations in insulin, GLP-1, and ghrelin concentrations that could potentially favor weight management, we postulated greater weight loss in the FO group. Indeed, in the pre-pandemic cohort of 24 participants (12 in each group), we did observe an average weight loss of 5.9 lbs vs. 1 lb in the FO vs. C groups. This difference attenuated over the pandemic period, when the once-monthly, in-person counseling sessions were converted into telemedicine appointments. We suspect the pre-COVID group had greater weight loss in part due to the in-person counseling visits and greater daily lifestyle stability, which may have led to greater effectiveness of FO counseling. Remarkably, while it has been shown that eating behavior changed during the COVID-19 pandemic with a shift toward increased snack frequency and preference for processed foods at the expense of fruits and vegetables [Our study is novel, being the first prospective study to investigate the feasibility and effectiveness of the carbohydrate-last food order behavioral intervention in prediabetes. The study design included parallel intensity arms and the use of uniform scripts for standard counseling and structured counseling materials for CHO-last food order counseling. The implementation of this intervention is simple as it builds upon the messaging of the widely used USDA MyPlate framework, emphasizing nutrient sequencing.Our study has limitations, including sample size and short study duration. As in most nutritional studies conducted in free living conditions, we had limited oversight of participants’ dietary intake. Dietary recall via self-reporting is commonly used for nutritional studies. However, the validity and reliability of dietary recall are limitations in nutrition trials. Additionally, adherence to carbohydrate-last food order behavior may be overestimated due to respondent bias given the nature of self-reporting [