Under what circumstances of livestock rearing might eating meat (instead of grain) represent a net gain for the human food supply?

To begin, we need to consider the factors that could result in a net gain for the human food supply when consuming meat instead of grain. These factors include: - Efficiency in converting feed to meat: This is the ratio of the input (feed) provided to the livestock to the output (meat) obtained from the livestock. - Type of feed: The type of feed used in livestock rearing affects the conversion efficiency. - Environment: The environmental conditions, like land availability and suitability for crop farming or livestock rearing, also contribute to the net gain.

To determine if consuming meat leads to a net food supply gain, we have to evaluate how efficiently livestock converts feed to meat. Generally, ruminant animals like cattle require more feed per unit of meat produced than monogastric animals (such as pigs and chickens). The less feed required for producing meat, the more advantageous it is to consume meat in terms of food supply.

Identifying the types of feed used in livestock rearing can also determine if eating meat results in a net food supply gain. If livestock primarily consumes feed that is not suitable for human consumption (for example, crop residues or low-quality grasses), then livestock rearing could be considered more efficient in terms of food supply. In this case, eating meat would not compete with the human grain supply and would lead to a net gain.

Finally, analyze the environmental conditions and land availability to understand when meat consumption could lead to a net food supply gain. In areas where land is unsuitable for crop farming but is suitable for livestock grazing, consuming meat could result in a net gain for the human food supply. Additionally, certain environmental conditions (e.g., climate, soil fertility) may favor livestock rearing over crop farming, making meat consumption more advantageous in terms of food supply. In summary, eating meat can represent a net gain for the human food supply under the following circumstances: 1. Livestock rearing is highly efficient in converting feed to meat, particularly when compared to grain production. 2. The feed used in livestock rearing is not suitable for human consumption, thus not competing with the human grain supply. 3. Land and environmental conditions favor livestock rearing over crop farming, making meat consumption more advantageous in terms of food supply.