diff --git a/qmemman/meminfo-writer.c b/qmemman/meminfo-writer.c
index df425b6..59ba5ed 100644
--- a/qmemman/meminfo-writer.c
+++ b/qmemman/meminfo-writer.c
@@ -64,6 +64,7 @@ const char *parse(const char *buf)
 	if (used_mem_diff < 0)
 		used_mem_diff = -used_mem_diff;
 	if (used_mem_diff > used_mem_change_threshold
+		|| prev_used_mem == 0
 	    || (used_mem > prev_used_mem && used_mem * 13 / 10 > MemTotal
 		&& used_mem_diff > used_mem_change_threshold/2)) {
 		prev_used_mem = used_mem;