This isn’t true in any way we could reasonably reach. The world has an insane amount of potential food output. A huge portion of the food the US produces goes directly in the trash instead of being used.
Do you have numbers ? There used to be famines. And countries still fight over water. what is the carrying capacity in terms of food production on earth ? 10 billion, 100 billion ? At a trillion, the world would be at Singapore’s population density I think.
The limit is ultimately set by thermodynamics and the need to dissipate waste heat to space. This limit is around 1 trillion people, but this likely requires food be artificially synthesized. Using conventional agriculture, a global limit of 150 billion was set (in a 1979 study referenced in the 1985 book "The Global Possible", page 217), or 47 billion with a US-like diet. Nitrous oxide emission from agriculture is likely to be a long term concern, as this powerful greenhouse gas accumulates.
As always, please do not interpret these statements as advocacy of these outcomes.
It's because I have constantly seen that misinterpretation. People seem to think that if I say "X is true" or "X is possible" then I'm saying "I find X desirable". This is a weird non sequitur and seems to be closely related to wishful thinking, that is the non sequitur of thinking that something is true because its truth would be desirable.
The world would get massively overpopulated very quickly.
Diseases maintain the balance of us with nature, if we eliminate them we are going to run out of food fast.