Why did food shortages create difficulties for Usman dan Fodio’s forces?

During the early stages of the jihad led by Usman dan Fodio, food shortages created significant difficulties for his forces because the military situation was initially unfavorable.1

To sustain his troops in the field, Usman’s forces resorted to the requisitioning of local food supplies. This practice caused two major problems:
* It antagonized the local peasantry, whose support was vital to the movement.1
* It increased the movement's dependence on powerful Fulani clan leaders who were capable of providing substantial forces, which in turn alienated non-Fulani groups.1

These logistical challenges and the resulting social friction were among the primary obstacles faced by the Fulani empire during its formative years.1