The World Food Programme says that about 8% of the hungry of the world are in a state of famine; they do not have enough food to survive. [WFP What is hunger?] The remaining 92% of the hungry have sufficient food for survival, but not sufficient food for good health; they are chronically undernourished.
Rice is a staple food because it provides high amounts of carbohydrates and some protein. Other staple foods, including grains and tubers, have a similar macronutrient profile: lots of carbs, and some protein, but very little fat.
Persons in a state of famine do not have enough kilocalories to survive, implying that they do not have enough carbs. Rice would go a long way toward ending a famine. At the very least, sufficient amounts of rice (or another staple food) would move those persons from a state of famine, to a state of hunger. They would then have sufficient food for survival, but not enough for good health.
However, as the 2008 FAO Hunger Report showed, the hungriest nations generally have sufficient carbs. What they lack is protein and fat. The 2008 Hunger Report presents a detailed nation-by-nation analysis of the hunger problem in each nation. The report lists the average per person macronutrient intake in each hungry nation, and whether the percent of that macronutrient is low, within recommended limits, or high. For every nation with a substantial hunger problem, the percent of carbs was either high or within recommended limits, whereas the percent of protein and/or fat was always low. This data proves the point that hunger is not primarily due to a lack of carbs, but a lack of protein and/or fat.
In my analysis, the hungry have the greatest need for fat, and a moderate need for some more protein. Some of the hungry also need additional carbs. But dietary fat is the largest part of the hunger problem. This is true because the staple crops of the world are high in carbs, moderate in protein, and low in fat. The hungry have enough food to survive, so they generally have enough carbs. Some of the hungry might be teetering on the edge between hunger and famine. So they would also need some more carbs. Their greatest need is for dietary fat.
Rice offers a high percent of carbs, a moderate percent of protein, and very little fat. According to the USDA National Nutrient Database, brown rice contains: 77.24% carbs, 7.94% protein, and 2.92% fat. White rice is only 0.66% fat. What the hungry need most, is what rice lacks: dietary fat.
Many of the hungry of the world already have some staple food, whether rice or wheat or maize or some other grain or tuber. They don’t need rice. They need a good quality inexpensive cooking oil. That would solve the hunger problem for the majority of the hungry. The remainder would also need some more protein. A small percent could benefit from additional carbs from rice or another staple food. But rice alone does not address the main cause of hunger: too little dietary fat.