Nicomachean Ethics III.11

Of the appetites some seem to be common, others to be peculiar to individuals and acquired; e.g. the appetite for food is natural, since every one who is without it craves for food or drink, and sometimes for both, and for love also (as Homer says) if he is young and lusty; but not every one craves for this or that kind of nourishment or love, nor for the same things. Hence such craving appears to be our very own.

That is straightforward enough.  

Yet [this craving of one's own] has of course something natural about it; for different things are pleasant to different kinds of people, and some things are more pleasant to every one than chance objects. Now in the natural appetites few go wrong, and only in one direction, that of excess; for to eat or drink whatever offers itself till one is surfeited is to exceed the natural amount, since natural appetite is the replenishment of one's deficiency.

This isn't strictly true, as we see e.g. in cases of anorexia, but he is correct that almost everyone only goes wrong in being excessive.

Hence these people are called belly-gods, this implying that they fill their belly beyond what is right. It is people of entirely slavish character that become like this.

There is a term that we might usefully recover: belly-gods! 

Aristotle believes in natural slavery, by which he means that some people are fitted out by their natures only to be slaves. Here is an example of someone who might be that way, because they are incapable of controlling even their most basic impulses. 

However, I note that in Iraq I observed that the very few genuinely obese men I met were sheikhs of one sort or another. In many cultures the ability to become fat is a demonstration of power, and a proof of command rather than slavishness. I wonder if Aristotle is merely encultured to the Greek approach here. 

But with regard to the pleasures peculiar to individuals many people go wrong and in many ways.

Our age has filled books on this topic -- mostly autobiographies by people proud of their errors. 

For while the people who are 'fond of so and so' are so called because they delight either in the wrong things, or more than most people do, or in the wrong way, the self-indulgent exceed in all three ways; they both delight in some things that they ought not to delight in (since they are hateful), and if one ought to delight in some of the things they delight in, they do so more than one ought and than most men do.

So, that's important to enumerate. 

Ways to go wrong in desire for food/drink/sex: 

1) Delighting in the wrong things, which are hateful things.
2) Delighting too much in the right things.
3) Delighting in the right things, but in the wrong way.
4) Doing all three of these at once ("self-indulgence"). 

Note another partial ad populum appeal: "more than one ought to and than most men do." There is a logos, sometimes, that lets us know what one 'ought' to do; but we must in other cases appeal to what is normal. Our culture has rejected both of those approaches: it rejects a logos based on any sort of human telos, and also rejects the idea that what is normal -- say, not being transgender -- should be a standard that is in any way binding. That's a challenge, particularly on matters of temperance (which, again, include all sexual pleasures).

Plainly, then, excess with regard to pleasures is self-indulgence and is culpable; with regard to pains one is not, as in the case of courage, called temperate for facing them or self-indulgent for not doing so, but the self-indulgent man is so called because he is pained more than he ought at not getting pleasant things (even his pain being caused by pleasure), and the temperate man is so called because he is not pained at the absence of what is pleasant and at his abstinence from it.

The self-indulgent man, then, craves for all pleasant things or those that are most pleasant, and is led by his appetite to choose these at the cost of everything else; hence he is pained both when he fails to get them and when he is merely craving for them (for appetite involves pain); but it seems absurd to be pained for the sake of pleasure.

There's a sort of non-logical contradiction, which is an odd entity: contradictions really only belong to logic, not to ethics in which strict logic doesn't (because it cannot) apply. This absurdity is thus analogous to a contradiction rather than a true contradiction (pace Hegel, who built his entire moral philosophy around 'contradictions' of this sort). Aristotle seems to have synthesized the law of non-contradiction into a form that we still use today and in a way that was central to his metaphysics, so even an analogy to a contradiction strikes him as absurd and offensive. 

People who fall short with regard to pleasures and delight in them less than they should are hardly found; for such insensibility is not human. Even the other animals distinguish different kinds of food and enjoy some and not others; and if there is any one who finds nothing pleasant and nothing more attractive than anything else, he must be something quite different from a man; this sort of person has not received a name because he hardly occurs.

There are enough of them these days that they have a flag and several names for variants. There are a lot more people now, however, so even that which 'hardly occurs' will occur when there are eight billion instances. 

The temperate man occupies a middle position with regard to these objects. For he neither enjoys the things that the self-indulgent man enjoys most-but rather dislikes them-nor in general the things that he should not, nor anything of this sort to excess, nor does he feel pain or craving when they are absent, or does so only to a moderate degree, and not more than he should, nor when he should not, and so on; but the things that, being pleasant, make for health or for good condition, he will desire moderately and as he should, and also other pleasant things if they are not hindrances to these ends, or contrary to what is noble, or beyond his means. For he who neglects these conditions loves such pleasures more than they are worth, but the temperate man is not that sort of person, but the sort of person that the right rule prescribes.

This having become so foundational a standard of Judeo-Christian ethics, it hardly needs elaboration.