No, if you implement a efficient system to transfer wealth, you don't subsidize meat as meat and plant based food are treated equally.

If a less lucky person (or what you call poor) receives money, they are still incentivized to spend the money efficiently. With the money they have available now, they can buy less meat but more plant based food than before.

We could for example lower taxes for those that earn least while increasing water and soil quality regulations (with matching tariffs for imports). This would increase food costs, which would hopefully match the money that people gained through lower taxes.

Meat would then become slightly more expensive than plant, but also have a major benefit for products that don't use a lot of water or harms the soil. Aquaculture would get a big boost, as would alternative method of meat production. The use of farm animals as an ecological alternative to using machinery to keep land clear of unwanted vegetation has become a niche method, and increased water and soil regulations would indirect benefit such farming alternatives.