They find that two key factors in explaining childhood dairy habits are GDP and relative milk prices. Dairy is relatively expensive in many of these countries, sometimes costing 20 times as much per calorie as staple crops such as wheat and rice. But in richer countries, the % of children consuming dairy every day is much higher. And in countries with the same level of wealth, children consume a lot more dairy when it’s cheap compared to other goods.
The paper looks at differences between countries, but these trends might also apply to changes within a country. As a country becomes richer, and if dairy prices in a country drop, childhood dairy consumption could increase sharply.
Indeed, the paper highlights an example of this happening in Vietnam. In less than 15 years, the number of Vietnamese children consuming cow’s milk daily catapulted from a mere 21% in 2000 to a staggering 71% in 2014, according to UNICEF data. This surge is especially remarkable given that most Vietnamese adults are lactose intolerant.