Stardate 20010703.0559 (On Screen): Hunger strikes can be effective tools of protest. Gandhi achieved great things using them. But they only work if there is a substantial number of people who care about the well-being of the striker or who would be intensely embarrassed by the death of the striker.
Occasionally the tactic is used in a situation where the people in power don't really care, and then it is useless. Peru's former spy chief Montesinos, one of the most hated men in the country, is on a hunger strike right now. I have a feeling that the consensus in Peru is probably "Fine, let him starve. It'll save us the cost of a hang-man's noose." (discuss)