Of course, even if all drugs were legalised, not everyone would become a drug addict. So a 17 or 18 per cent reduction in labour productivity for drug users might not be enough on its own to offset a 20 per cent reduction in GDP by 2020 (relative to a non-Green economy). But the Greens are not finished yet with their efforts to reduce productivity. We are apparently all to be encouraged to move away from meat. Obviously meat provides very concentrated nutrition. For those with appropriate self-discipline and the motivation to do it, studies suggest that vegetarian diets need not be damaging to productivity (indeed, for some individuals they may even increase productivity). But for the average worker-eater, being forced into a vegetarian diet and away from meat-eating is likely to induce at the very least quite material transitional costs. Lacking the concentrated stores of energy that meat provides and lacking, as yet, the competence to provide an even flow of nutrition from a vegetarian diet, energy and concentration levels are likely to wander, with hungry tempers flaring and cooperation undermined.