Author and activist Michael Pollan says, “Eat food. Not too much. Mostly plants.”

In my life of plenty, I think about that advice a lot.

But I often wonder how such admonitions to an over-fed nation must play in other parts of the world. The thought makes me cringe. In the poorest countries, people don’t worry about eating too much or too much of the wrong thing. They worry about eating at all.

Feeding a household can consume 70 percent of a family’s income. And that doesn’t take into account the hard labor that goes into coaxing staples like teff or manioc from fields that could be bone dry, depleted of nutrients, or must be tilled without the benefit of a tractor or even a draft animal.

Last summer, I watched as a farmer lurched through a field of stones—so many I wondered where the seeds would find room to sprout—straining to keep his ox-drawn plow headed straight. We were in Tigray, a region of northern Ethiopia blanketed with poverty and prone to drought. What hope did the farmer have that his crop would thrive? And what choice did he have but to keep at it? The mercilessness of toiling for an uncertain harvest seemed sharper even than the stones under his feet.

And that’s why the optimism of a farmer I met in Haiti last month has stuck with me. His name is Scheler “Tipape” Cenoble and for three years he’s been working a plot of land to feed his family—ever since the taxi he drove for a living broke down and he had no money to fix it. For the last two years, he said, his fields have turned a profit thanks, in part, to guidance from Anger Techler, a hugely energetic agricultural technician working with an Oxfam partner.

Cenoble’s field slopes slightly and when it rains hard, the water rushes off. With direction from Techler, Cenoble built a “dry wall”—like a small dam made of rocks—to prevent the water from running away and taking the new shoots and soil with it. And he learned about proper positioning and measurements to make the wall more effective.

“Without knowledge, you can’t do anything,” said Cenoble.

He’s so right.

So when some of the world’s leaders meet next week for meetings of the G8 and G20 countries, I hope they give concentrated attention to the problem of global hunger and remember Cenoble’s simple equation: knowledge equals independence; learning a better way to farm equals food on the table.