How will consumers react to the recession as it deepens? The current search for lowest prices or best value will obviously intensify, squeezing retail margins and costs still further. More bad news for those who have staked everything on the organic market or some other high-priced premium product. More market power in the hands of the big battalions of the grocery industry as brand strength and scale economies ensure survival and smaller players with neither of these advantages go to the wall.
Somewhat less predictable is the impact of the downturn on what people actually eat. Not long ago Andrew Lansley, Conservative spokesman on health policy, brought the roof down on his head by suggesting that a shortage of money might induce people to eat more frugally and, by implication, healthily. That may well be true of some consumers but the converse - that many others will find relief from personal anxiety in "comfort" food - is also plausible.
All this particular spat did was to remind us that broad generalisations about what consumers will or won't do in a recession whose depths have yet to be plumbed are a very dodgy basis for policy. Simplistic extrapolations of current trends in the obesity statistics are similarly open to challenge.
Which brings us to the £200m advertising campaign aimed at reforming the eating habits of those consumers who are either obese now or thinking of becoming so in the future. If obesity and the lifestyles that drive it were the result of widespread ignorance of the alternatives, one could perhaps see some point in this campaign. But research by the IGD, the FSA and others over the past few years suggests otherwise. Most people seem to be aware of what they ought to be doing and many of them are giving it a try. The rest need motivation, not more sermonising.
The grocery industry has done an enormous amount over the past 15 years or so to make healthier food more available and appealing. If too many people are still taking in more calories than they are burning up, consider the lifestyles they have chosen. For single-issue fanatics, however, it's much more comforting to advocate fixing salt, fat and sugar content by law - the epitome of the nanny state. In the words of former Canadian prime minister Lester Pearson, "We'll jump off that bridge when we come to it."