Obesity is immoral for the food that is wasted, how it drives up health insurance premiums, how it normalises being unhealthy and of course how bad it it for the environment. Think about it an obese person eats maybe at least 4 times what a person at a healthy weight eats which means higher carbon emissions to both produce, transport and cook the food, then there's the extra weight and space they take up in aircraft, buses, trains, ferries. Even their own cars use more gas and need maintenance more often. Also of course obese people use more air-conditioned. They also require more fabric to cloth them. They also use more water and soap to wash.
We need to round them all up and concentrate them in special fat camps until they lose weight.