Just a sidenote: I made my graduation and master degree about jesuits in Japan and how the perspective of death changed for the converted christians. Readint the missivas - the jesuit letters - I found a lot, really a lot, of japanese who converted for the sake of eat meat. Yes, cow meat. Jesuits had a big impact on the japanese cousine, like Kasutera (castle, a kind of bread) and Tempura (tempero - salt and the kinds), adding meat on local dishes. (Sorry for any mistakes, not a native english speaker)

Any sources on the population of Christians who practice, but don't believe?

While we can argue over how appealing Christanity was in Asia, Africa is a more straightforward case. 63% of the population of Sub-Saharan Africa identifies as Christian, and 1 in every 4 Christians in the world lives in Africa (http://www.pewforum.org/2011/12/19/global-christianity-exec/). Notably, the 20th century also saw widespread conversion to Islam on the continent, which suggests that our explanations should not focus narrowly on Christianity.

Unsurprisingly, the reasons for this are contested among historians. Robin Horton famously argued that monotheism made more sense to Africans during colonialism because people began to think of themselves as part of larger-scale communities, and therefore indigenous local deities no longer seemed sufficient for explaining the world (Robin Horton, "African Conversion," Africa 41:2, 1971). However, there are some other obvious reasons for conversion. In almost all European colonies in Africa (particularly outside the Islamic zone) European colonizers actively supported Christian missionaries. Almost all schools were controlled by missionaries or actively encouraged conversion, so sustained interaction with the Christian church was necessary for acquiring literacy and, therefore, for many economic opportunities. Especially for socially marginal people, conversion to Christianity provided the opportunity to improve their social status and economic position by gaining the patronage of missionaries.

On the other hand, it's important to think critically about what "conversion" looks like. As many scholars have argued (JDY Peel perhaps most famously), many African churches include theological elements that are derived from precolonial religious beliefs. Some churches also include newer prophets that would not be recognized by 'orthodox' churches in the West. In South Africa, for example, members of the Shembe church self-identify as Christian, but recognize Isaiah Shembe as a prophet on par with Jesus; another example of this is the Kimbanguist church in West-Central Africa.

There's a bit I can tell you about Christianity in Indonesia. For sources I'd have to look through my dad's library, however, or at the very least give him a call. This is from memory. My dad is a Church historian with an interest in Indonesian missionary history and this was dinner table talk when I grew up.

The Dutch colonial government only allowed missionaries, both Catholic and Protestant, to work in regions where Islam was either weak or nonexistent to avoid them stirring up unrest by confronting an established religion with a missionary zeal of its own (for similar reasons missionaries were also forbidden to work in Bali, where something resembling Hinduism was strong). As a result attempts at spreading Christianity only happened in regions that had for some reason (rugged geography and isolation, mostly) managed to remain outside of the Islamic mainstream of Indonesia for hundreds of years.

Now, not only had those regions managed to remain outside of the Islamic mainstream, they also had much less in the way of organized states and technology. As a result, the people who lived there were mightily impressed when white missionaries entered their lands bringing marvels of technology, such as steel, literacy and medicine. They were therefore more than willing to adapt the accompanying religion as well. After all, any technology sufficiently advanced will seem like magic, and the missionaries mainly targeted areas that were either still living in the stone age, so to speak, or had barely outgrown it. Taking up Christianity to accompany steel axes and antibiotics must have seemed like a pretty sweet deal to the people of Toraja, Papua and the Batak highlands.

To sweeten the deal, once these formerly "primitives" regions were Christianized, the Dutch started recruiting their local assistants from them. People like elementary school teachers, lower level civil servants and NCOs in the colonial army were recruited not from the much larger populations of Java, Bali and Southern Sumatra but from the small but Christian (and therefore "dependable") populations of places like Ambon and the Minahasa. Christianity therefore not only became associated with the modernity of the Dutch colonizers, but with comparative prestige in the colonial society of the Indies as well.

The results of this policy have lingered to this day. Despite forming only a tiny minority of the total Indonesian population, Minahasans, Bataks and other Christianized Indonesians occupy more positions of importance than one would expect given their small numbers. As a result, even in the most populous Islamic nation of Indonesia, Christianity retains a surprising amount of appeal.