Let $\gamma :[0,1] \mapsto \mathbb{R}^{n}$ be a curve such that all the leading principal minors of the matrix $(\gamma^{(1)}(t), \ldots, \gamma^{(n)}(t))$ are nonvanishing as $t \in [0,1]$. 

Theorem: the minimal number $k$ points required to represent any interior point of  $\mathrm{Conv}(\gamma([0,1]))$ as a convex combination of $k$ points of $\gamma([0,1])$ equals $\lfloor \frac{n}{2}\rfloor+1$.

Moreover, if $n\geq 3$ is even the corresponding convex combination will always contain one of the endpoints $\gamma(0)$ and $\gamma(1)$. And if $n$ is odd then the convex combination will never contain any of these endpoints.