Understanding weight regain after a nutritional weight loss intervention: Systematic review and meta-analysis

The purpose of this systematic review was to analyze the effects of lifestyle interventions on long-term weight maintenance of weight loss. In addition, we seek to address which period is most susceptible to weight regain; and what is the time required for following-up weight maintenance after the intervention.Articles published up to August 2020 were identified using the Medline (PubMed), Embase, Web of Science, CENTRAL and Scopus.After the selection process, 27 clinical trials involving 7236 individuals were included. The results showed that around 36 weeks after the end of the intervention, weight variation reduces, and a sign of continuous weight gain begin to occur with some patients (n = 208,209) presenting even a completely regain of the lost weight before one year (∼40-48 weeks). However, some strategies used during the weight loss intervention and maintenance period may impact the amount and when the weight regain happens, like intervention type;, intervention duration;, presence of dietitian on the care team;, and maintenance period with counseling by a health professional at least once a month.This systematic review and meta-analysis showed that lifestyle interventions remained effective in maintaining the mean weight (5% lower than baseline weight) after weight loss interventions were over. However, weight regain started 36 weeks after intervention conclusion. And, it turns out, some strategies used during the weight loss intervention and maintenance period may impact the amount and when the weight regain happens. Obesity complexity and chronicity should be considered, therefore constant and lifelong monitoring and support are important.