Is Earth losing its food supply?

China is buying huge amounts of land in Africa to farm.. They will have food for their people while everyone else starves.. They are also buying up all the natural resources around the globe.. While we argue about stupid stuff like climate change.. 

No, not at all. We're producing more food today than we ever have. And we produce more than enough to feed the world's population. 

If population growth continues at its current rate, there are some concerns about the future, but for now, we're good. 

Sure, but not for the  First Time

Disease, War, Homosexuality, Famine usually Level things out over time

Technology also helps. Until the Luddites get involved.

Luddites of old equal the Greenies of today.

No.  But the demand is exceeding the supply.  But don't despair.  There are all kinds of research programs ongoing where food plants are being caused to produce more and more food material.  So the supply of food will start to catch up with the demand.

The real issues are the food chains.  Growing the food is a snap, but processing and delivering it to the consumers are more problematic.  Politics often bans food from being distributed.  Broken or non-existing roads and rails make moving food to the users a major issue.  And large scale poverty makes food unaffordable in many nations.

My point.  The supply of food is not the issue.  The distribution of the food to users is the issue.