I mean, it's not really fair because plants don't have any of the same "parts" we do that would constitute a body as such. When I think of growing my body, I think of organs and tissues such as muscle, bone, blood, neurons, etc. These are primary components of what would be considered nutritional intake from a dead body that would be reconstructed for use in our own body. Plants do not have muscles, bones, etc. We are using basic nutrients like cats, proteins, and carbohydrates as building blocks for our own parts. As noted elsewhere it takes a fraction of the plant matter necessary to build our own muscles than it does to feed a pound of meat to them use to build muscle from that. So even by your flawed logic, it's still less plants to eat them directly than it is to eat meat grown from them.

Additionally, the vast majority of plant products don't even require a plant to "die" to eat. Many fruits and vegetables are just the reproductive structure of the plant, not vital for the health of the plant at all. I am an avid gardener and the only plants I can think of that have to "die" for me to eat them are root vegetables. Even then if you're diligent you could save, for example, the tops of carrots or bottom of onions to regrow.

They are completely different concepts and it's bad faith to argue otherwise.