[sacado2]

Not OP but I'd say it's the shortest path to obesity, unless you have a very strong will.

I never buy anything at the automated machines at my workplace, but when my colleagues bring some food for others to share, I always take some, for instance.

[SECProto]

Depending what's available. At my job, if I forget my lunch, my only option is driving to a fast-food joint. If my employer offered snacks (some healthy, some not), I'd likely end up healthier. It's situational, depends on the person and workplace. Willpower is only a small part of it (at least for me).