It is common for normal weight people to look down on heavyset individuals without even trying to understand why they are overweight. Discriminating against someone who gains weight because they can not control the feelings of hunger and urge to eat due to medication or being born with an altered brain chemistry imbalance is no different than mistreating another person due to their being born male or female.
There may be few clinical studies documenting one’s chemical imbalance causing people to eat more and more, but anecdotal evidence are littered throughout the internet retelling stories of individuals who experienced excessive weight gain when taking anti-depressant drugs (or similar medication trigger the chemical imbalance). As told: “Everything became difficult to concentrate on other than food”.
Once they were off the medication, they were able to lose the weight because the urges to eat the instant they felt hungry had disappeared.
There may be no perfect solution to fighting obesity, but there can be more acceptance of the fact that people are born different with issues beyond their control without even knowing it, such as having a bigger appetite and feeling hungry all the time.