Yet pressure from food companies has led to a "minimal" blacklist, allowing the continued sale of cakes and refrescos, says Dr Villa Romero.

In much of the globe it is impossible to do business without paying backhanders, from Mexico's “refrescos” to North Africa's “petits cadeaux” (see article).

Within five years, says Cuauhtémoc Mancha, who runs the programme, “we hope to see a new generation that drinks water rather than refrescos and prefers fresh meals to industrial food.