I think people are kind of missing the point. It's not that some food is more expensive for the poor. It's that, generally, things are more expensive for the poor. I have a laptop in my house that I can search job ads with, read about my field of work, or use for another gazillions things whenever I have a free moment. If you cannot afford a computer and internet, then you're 'paying' for a similar thing with commute time, as you go to the library to use their computers. My library is pretty close, and it's still a 10 minute jog away. If I needed to jog 10 minutes to use my laptop, I'd get much less out of it.
Credit is more expensive, which makes it harder for someone with a really good idea to turn profitable. Etc.
It's not the whole story. The real low hanging fruit is decent jobs. employed people can be effectively poor if those things he mentioned are a problem. What about the millions of people who simply cannot find decent work?
They should cut their drinking, smoking, and cable? Any social welfare system: from welfare cheques to subsidized healthcare will be more effective if people are being wiser.
Yes, obviously we need to increase available jobs. We need to be moving capital and entrepreneurship around as much as possible. Anyone can be an entrepreneur and employ people. But Patroklos is talking about situations that I know about too. Someone is poor, but then spends upwards of 20% of their income on things that I don't buy.
On the whole, people value the short-term more than the long-term. Part of accumulating wealth is overcoming that instinct.