Images of the Post Snap Famine
With the population halved, most of the world at least experienced disruptions and shortages with many farmers and those working on Farms removed. Countries with large amounts of farmland were able to at least prevent people from starving within the first year, poorer countries or those already experiencing famine, ended up far worse off.
British Marines bring food and water to a coastal West African Village. The Marines later admitted that such measure wouldn't be nearly enough to feed every country who's supply of food was disrupted by the Snap.
However, more permanent solutions were sought almost immediately. After Tony Stark decided to stop selling weapons and move his company more towards developing medicine, GMOs, and alternate energy sources, many decried it as an impulsive and naive business choice. In hindsight that decision is probably what kept many more people fed. Labs such as the one pictured worked overtime to produce crops with higher yield and resistance to drought.