[Meal replacement efficacy on long-term weight loss: a systematic review]

Meal replacement (MR) has been frequently used to substitute one or more meals during the day. However, few randomized long-term studies have assessed its efficacy.

To asses meal replacement use and its effectiveness on long-term weight loss (> 1 year) in overweight and obese people with or without diabetes.

A search of randomized clinical trials with an intervention period equal to or more than a year, published on Pubmed, EBSCO host and SciELO through November 2010 was performed. Mesh terms such as "meal replacement", "weight loss," "overweight," "obesity" and "diabetes" were used, plus the term "meal replacement." GRADE scale was used to assess the quality of the studies.

Seven studies met the inclusion criteria and were analyzed. It was observed that four of the studies showed a major weight loss in meal replacement groups, but in the other four studies no significant difference in weight loss was found.

The evidence of the beneficial effect of meal replacement on long-term weight loss is inconclusive. These results warrant longer and better design studies.