President Reagan was bound to be controversial when he met with leaders of rich and poor countries in Cancun, Mexico. Most participants urged a radical new assault on world hunger and poverty through ''global negotiations'' and the transfer of vast new economic resources to needy countries. Mr. Reagan, on the other hand, wants resources to be generated through private business initiatives , a freer world trading climate, and greater self-help in the poor countries themselves.
Mr. Reagan thus appeared to be the odd man out. In the long run, however, he could prove to be the ''odd man in.'' His approach has obvious shortcomings. But it also highlights some critical needs.
Private enterprise, for one thing, indeed play a greater role. The possibilities are largely unexplored. And greater private involvement could lead to a balance of private and public efforts in some developing countries - especially those where efforts to deal with hunger and poverty have been bogged down by bloated government bureaucracies that are inefficient and corrupt. In many African nations, for instance, the growth of governmemt employees in agriculture has risen 10 to 15 percent per year. In Tanzania, experts believe, this has sapped the strength of otherwise ambitious development plans.
The US President's stress on the need for greater self-reliance in the poor countries could also reinforce initiatives already underway in the United Nations and the World Food Council. These organizations have been working with developing countries on national strategies to become more food self-sufficient, less dependent on aid. Also, Mr. Reagan's promotion of a freer world trading climate - if he is serious about it - could be a boon. Last year the developing nations took $600 billion from their exports - 20 times the amount they received from aid.
Developing countries are understandably disgruntled by the President's opposition to global negotiations that would restructure the world economy and boost aid flows from rich to poor. They are convinced that the international financial system works unfairly against them, and that the interrelated problems of hunger, poverty, debt, and energy must be considered as a whole.
But increased spending and comprehensive discussions may be an unrealistic hope as the industrialized countries come under increasing pressure to tighten their own belts. Mr. Reagan has built his whole political base on the promise of cutting government spending and easing inflation. Given these political realities, the developing countries may have come away from Cancun with more cooper-ation from the US than was earlier thought possible. The President even committed the US to participate in future global negotiations, albeit with some stringent conditions.
This is not to say that Mr. Reagan's approach is without serious flaws and hazards. It is unrealistic, for instance, to expect that the benefits of expanded business investment in the third world would automatically ''trickle down'' to the poor and hungry.
Take India. There, increased initiatives by private enterprise in the food sector have led to remarkable increases in food production - even the storage of huge reserve stocks. Nevertheless, the number of people suffering malnutrition has actually increased.
It is also unrealistic to expect that the bulk of capital needed for development in the impoverished countries would actually be volunteered by private investors. The risks of investing in poor countries are often extremely high. Corporations typically invest in projects to extract raw materials and minerals for profit, not in projects that will develop desperately needed food production.
If private initiative is to prove meaningful for the 500 million people estimated to suffer severe malnutrition, Mr. Reagan will have to come up with practical ways to link such initiative with the needs of the developing world. This might take form in new plans to reduce the risks of private investment in the third world - perhaps through well-monitored loan insurance schemes administered by the World Bank. Also, nonprofit institutes could be launched to help direct private investment from the industrialized countries in ways sensitized to the needs of developing countries.
Nevertheless, increased private investment, however helpful, will be no substitute for the continued development initiatives of the international banks - and strong US support for these institutions. Although Mr. Rea-gan claims to recognize this, his resolve seems less than certain. The US has so far opposed formation of a new energy affiliate at the World Bank which could help poor countries cope with the rising costs of meeting energy needs (a concept that has support from the OPEC and European leaders at Cancun). And US funding for the international banks, which Mr. Reagan says he still favors, currently hangs in the balance in Congress. Without strong administration support, funding could fall back to last year's level and leave the banks with only half the money proposed by the administration.
It is decisions in these areas which will ultimately say most about the President's resolve to help the world's destitute and hungry. On an issue where easy rhetoric has all too often been substituted for concrete deeds, Mr. Reagan could surprise the skeptics and disarm his critics by coming through with action to back his words.