This study has both strengths and limitations, especially with regard to the design and data analysis strategy. A key strength is the randomized controlled trial design which enables increased internal validity and decreases several sources of bias, including selection bias and confounding. In addition, it was also designed as a pragmatic trial, with the protocol reflecting efforts to replicate the real-world environment by not supplying meal replacements or food. Notably, only 9 patients could not comply with the protocol, indicating that acceptability of the diet protocol was high. However, as this was only a 6-month long study, further studies are needed to determine whether a 5:2 diet is sustainable (and effective) in the long-term compared with CER, which the authors highlight. The study was also adequately powered to detect clinically meaningful differences in weight loss and SBP, and appropriate analyses were performed on both the basis of completers and on an intention-to-treat principle. However, further studies are needed that are adequately powered to also detect clinically meaningful differences in the other measures, ie, body composition, HbA1c, and blood lipid levels. Importantly, generalizability of findings from this study is limited as the study population comprises only Chinese adults, predominately middle-aged, overweight, and had mildly to moderately elevated SBP and DBP, and excluded diabetic patients. Thus, findings are not necessarily applicable to individuals with highly elevated blood pressure or poorly controlled diabetes.
Applications for Clinical Practice
Results of this study demonstrated that IER is an effective alternative diet strategy for weight loss and blood pressure control in overweight and obese patients with hypertension and is comparable to CER. This is relevant for clinical practice as IER may be easier to maintain in this population compared to continuous weight-loss diets. Importantly, both types of calorie restriction require clinical oversight as medication changes and periodic monitoring of hypotensive and hypoglycemic episodes are needed. Clinicians should consider what is feasible and sustainable for their patients when recommending intermittent energy restriction.
Financial disclosures: None.