it's a common belief that training with light weights with high
reps makes you more lean, however light weights high reps only
activate slow twitch muscles that has the least growth ability.
High reps light weight sometimes will also activate muscle groups
that are harder to hit and recruited with heavy weights low
reps.
Its the diet and cardio frequency cum intensity that causes you
body to be lean.
heavy weights low reps activate fast twitch muscles that will cause
growth in muscle, however training with heavy weights low reps can
also give you a lean tone if trained correctly