Laziness is too broad a criticism. Chronic illness and disability are often to blame. Encouragement and practical dietary advice are the best approach.
I accept that to a degree, and certainly where medical, genetic and other factors beyond the control of the individual come into play, I completely understand it.
That said, a LOT of obesity is due to a simple lack of discipline. I am a foodie; I love to eat, but as my work has made me a lot more sedentary than I used to be, I've cut my intake substantially, and have become far more attentive to what I'm eating.
I say that with no intention whatsoever of elevating myself above others, but to the contrary, to say I'm nothing special and if I can do it, pretty much anybody can if they simply exercise the discipline to do so.