Intermittent energy restriction bests continuous energy restriction for weight loss

In 2015, the overall prevalence of obesity (BMI ≥ 30 kg/m2) worldwide was 5.0% (107.7 million) among children and 12.0% (603.7 million) among adults, as reported by the Global Burden of Disease study. Weight loss can be achieved by either lifestyle modification or Pharmacotherapy such as medical devices or bariatric surgery. Continuous energy restriction (CER) involving a daily energy deficit of 500 to 750 kcal is recommended as a traditional weight management strategy. However, many individuals find it difficult to adhere to CER because energy must be limited every day. Intermittent energy restriction (IER), also called intermittent fasting, has gradually attracted attention and popularity in the past few decades. IER typically involves periods of energy restriction (a very low‐energy diet, approximately 500‐600 kcal/d) alternating with periods of unrestricted food intake. However, an overall evaluation of the impact of IER (the 5:2 diet and ADF [Alternate Diet Fasting]) versus CER regimens on weight loss, multiple metabolic variables, percentage of weight loss consisting of fat mass (FM), and percentage of weight loss consisting of fat‐free mass (FFM), as well as inflammation factors, is at present lacking. Therefore, a research team of China conducted a study to evaluate the effects of intermittent energy restriction (IER; only for 2‐3 d/wk) versus continuous energy restriction (CER) on weight loss and metabolic outcomes in adults with overweight or obesity.

It was a systemic review and meta-analysis which involved searching of databases from the last decade to December 18, 2019, for randomized controlled trials (RCTs) that assessed weight loss and metabolic outcomes in IER and CER. Researchers identified 3,754 records, and included 11 RCTs (n = 850) for analysis. They used RevMan version 5.3 software for statistical analysis of the data and the effect sizes were expressed as weight mean differences and 95% of Confidence Interval.

Upon analysis, they found that participants in the IER group lost more weight and presented with greater improvement in insulin sensitivity than participants in the CER group. In a subgroup analysis, they found that absolute weight loss (WMD: −0.95 kg) and percentage of weight loss (WMD: −1%) was greater for IER than for CER which implies that short‐term interventions with IER were associated with increased weight loss. However, they found no evidence to suggest that IER is easier to maintain over the long term.

The authors concluded, "This systematic review shows that IER (2‐3 d/wk) had greater effects on short‐term weight loss than CER and that IER results in comparative metabolic improvements. Furthermore, longer RCTs are needed to validate these findings".

For further information:

https://onlinelibrary.wiley.com/doi/full/10.1002/oby.23023?af=R