The unpolarized spin-flip isoscalar generalized parton distribution function $({E}^{u}+{E}^{d})(x,\ensuremath{\xi},t)$ is studied in the large-${N}_{c}$ limit at a low normalization point in the framework of the chiral quark-soliton model. This is the first study of generalized parton distribution functions in this model, which appear only at the subleading order in the large-${N}_{c}$ limit. Particular emphasis is put therefore on the demonstration of the theoretical consistency of the approach. The forward limit of $({E}^{u}+{E}^{d})(x,\ensuremath{\xi},t)$ of which only the first moment--the anomalous isoscalar magnetic moment of the nucleon--is known phenomenologically, is computed numerically. Observables sensitive to $({E}^{u}+{E}^{d})(x,\ensuremath{\xi},t)$ are discussed.