A 2007 article from Church History examines the role of fasting in French Reformed piety, and concludes with this:

“Why did the fast acquire this remarkable status and power in the Reformed world, particularly in France? The response, in part, relates to Reformed Protestants’ deep reverence for Scripture and its authority. They were profoundly inspired by the Hebrew Bible. The fast was a concrete liturgical link with ancient patriarchal predecessors who were self-consciously God’s ‘chosen.’ Reformed Christians possessed, of course, a strong notion of election, frequently cast themselves as the community of the saints, and often borrowed imagery and language from the Hebrew Bible to express this perception . . . .

“In addition, French Protestants, much as the ancient Israelites, were a persecuted and suffering people. The very vocabulary of humiliation and appeasing God’s anger and ire evokes this image and a ready appreciation of the reality behind it. French Reformed Protestants lived in close proximity with their Catholic confessional rivals and, accordingly, were less inclined to accommodate certain medieval aspects of fasting. They only occasionally held fasts prior to celebration of the Lord’s Supper and sought to avoid a springtime expression that came dangerously close to approximating Lent such as occurred among their Scottish Presbyterian brethren. Conversely, they understood that Catholics frequently interpreted their fasts as acts directed ‘against public tranquility and the authority of the superior powers.’

“Reformed Protestants did not deploy the fast with its renunciation of the physical requirements of the body and simultaneous amplification of the spiritual dimension in the same fashion as their medieval ancestors or Catholic adversaries. Lenten and Advent fasts were collective in the sense that individuals fasted simultaneously and in similar ways; on the other hand, people rarely gathered for the event. When Reformed believers fasted, they gathered in time and space; they formed a spiritual ‘body’ of Christians who collectively denied their real bodies food and drink. Together, they fasted in the expectation of becoming one people, sharing their communal suffering and cementing the unity required for struggling with adversity. Furthermore, although the faithful refrained from eating and drinking during the day-long Reformed fast, the mortification of the flesh was not the preeminent element in this religious ritual. Rather, the spiritual dynamic eclipsed the physical. The act of fasting—renouncing the dietary demands of the human body—while not incidental to the liturgical event, did not in itself purify. Rather, it was the pure Word of God sung in the psalms, heard in readings from Scripture, and explained in the pastor’s sermons that nourished, in this instance, people’s souls. Of course, the Reformed fast deprived the believer of physical sustenance, even as it fed the spirit. In the ritual, people drew together corporeally in the temple to regenerate their spiritual attachments through collective song or sitting as a single body to hear the sermon focusing on God’s Word. While food sustained human existence in the present, entirely transitory world, it was Holy Writ and its divine promise of eternal life that the human being ultimately sought. The fast served to meet the profound spiritual needs of those who made up the religious community.

“Certain practical aspects of people’s everyday devotional habits also help to explain the popularity of the fast among French Protestants. The Reformed liturgy for fasting was wholly distinctive and readily distinguished from medieval and Catholic approaches. As such, it contributed significantly to the manner by which the participants defined themselves as members of a religious community. Reformed congregations simply did not have the abundant means for public expression of piety as did Catholics. Protestants in France did not celebrate births, marriages, and deaths with feasts, dances, and processions. They had no equivalent to Catholic penitential confraternities with their public, frequently confrontational displays of religiosity. The extremely popular feast of Corpus Christi, for instance, with its public processions and various other corporate devotional elements had no analogue in Protestantism with the possible exception of the collective singing of psalms in the temple and occasionally in the streets. Sermon services, though they could at times be stirring, were primarily moments for intellectual edification, and the quarterly celebration of the Lord’s Supper was wholly unpretentious and relatively unemotional. Even the buildings for French Reformed worship were plain and unadorned. These elements possessed an appealingly spare and simple elegance, but they were also exceedingly restrained. When the Reformed community chose to address grave religious and political concerns, the fast with its overpowering foundations in Holy Scripture was among the few publicly shared liturgical ceremonies to which the faithful could turn for emotional satisfaction and public expression of their anguish. The experience appears to have had the capacity to move at least some in the congregation to tears. In the end, fasting may not have been considered a work of merit. Yet the ritual unquestionably became a powerful instrument for a hard-pressed religious minority to announce and verify vigorous attachments and enduring harmony. It strengthened collective religious identity and affirmed communal accord. ”