An average dog might prefer, say, chocolate over dry kibble. Yet an average dog owner has no qualms about ignoring the dog’s preferences and feeding the dog kibble over chocolate. Chocolate can kill a dog.
In the same way, an average human might prefer, say, soft drinks over water. Excessive soft drink consumption leads to a variety of health problems, such as increased risk of diabetes. Yet any attempt to encourage people to consume water rather than soft drinks through, for example, soda taxes, or bans on super-size soft drinks, is extremely controversial.
Why is it acceptable to limit animals’ choices, but not humans’?
Any economists who find this inherently daft might want to revisit Singer’s work on the subject from a utilitarian perspective.