A systematic review including 31 studies with a total of 968 subjects was abstracted in DARE. The authors state that pooling of 4 studies showed a significant beneficial effect of fasting followed by a vegetarian diet. When the 2 non-randomised trials were excluded the improvement remained significant.
Comment: The quality of evidence is downgraded by potential reporting bias (only small heterogenous trials reported) and review quality (inappropriate pooling of data).