Which of the following is a major challenge in food sustainability?

The major challenge in food sustainability highlighted here is that a significant portion of food—around 50%—is wasted. This waste occurs at various stages of the food supply chain, from production and processing to retail and consumption. When food is wasted, it not only represents a loss of resources such as water, labor, and energy that went into producing it but also contributes to environmental issues including greenhouse gas emissions when organic waste decomposes in landfills. Addressing food waste is crucial because it directly touches on the need for more efficient use of resources and improving food security by ensuring that more of the food produced reaches consumers instead of being discarded.

In comparison, while factors like excessive consumption habits and a shortage of farm workers are indeed challenges to food sustainability, they do not encapsulate the same level of immediate impact and systemic inefficiency as the sheer volume of waste generated. Additionally, having too many farming practices can create confusion or inconsistency but does not have the same direct effect on the sustainability of food resources as waste does.