  We prove a minimum degree version of the Kruskal--Katona theorem: given $d\ge
1/4$ and a triple system $F$ on $n$ vertices with minimum degree at least
$d\binom n2$, we obtain asymptotically tight lower bounds for the size of its
shadow. Equivalently, for $t\ge n/2-1$, we asymptotically determine the minimum
size of a graph on $n$ vertices, in which every vertex is contained in at least
$\binom t2$ triangles. This can be viewed as a variant of the
Rademacher--Tur\'an problem.
