"they are adverse because they are unhealthy for consumption"
Like rocks, thumbtacks, shampoo, too much aspirin, bacon-double-cheeseburgers and daytime TV. We do not ban everything that's unhealthy. The question is whether, on balance, the benefits of prohibition are greater than the costs. I think we agree on that, though we might disagree when we estimate the balance when it comes to narcotics. Unfortunately, statistics for both sides are limited. This scarcity of data makes the Portugese experience really valuable.
We can know the cost of imprisoning all these people though. The US has the highest imprisonment rate in the world: 738 per 100,000. The UK, which has similar societal attitudes to drugs, though very different judicial policies, has 148 per 100,000, which is still above the median globally. US taxpayers are spending too much money on food, lodging and security for drug offenders.
Imprisonment data:
http://www.kcl.ac.uk/depsta/law/research/icps/downloads/worl...
edit: in case you think the cultural differences with the UK make the comparison poor, Canada has 107 prisoners per 100,000 population. That's one seventh the rate of their neighbor.