He doesn't suggest eating off the dollar menu as the way to save money. Rather, if you do eat at McDonalds, eat off the dollar menu. Subtle, but distinct difference.
Also, the food at the local lunch spot may be higher quality, but it is very likely to have tons of added salt, fat, oil, sugar and other deliciousness that is just as likely to land you in the hospital later in life.
His best advice is probably to avoid eating out in general.
