What detail about the deep-frying tradition near the Meuse Valley causes some historians to express doubt regarding the Belgian origin story?

Peasants lacked the necessary fat reserves to cook large quantities of potatoes

While the narrative describing Belgian villagers substituting fried potatoes for fried fish during winter freezes is persistent, some historians raise valid critiques regarding its feasibility for the peasant class of the late 17th or early 18th centuries. A primary point of contention revolves around available resources. Deep-frying food requires a substantial amount of cooking fat. Skeptics argue that peasants, who often lived close to subsistence levels, would not have possessed the necessary surplus fat reserves to sustain the regular deep-frying of large quantities of potatoes, especially if they relied on preserved fats sparingly. Furthermore, some doubts center on the early prevalence of the potato crop itself in that specific region prior to the alleged deep-frying tradition.