The index, a measure of the monthly change in international prices of a basket of food commodities, stood at 169.8 points in December 2017, down 3.3 percent from November.
Despite the late-year slide, the FAO Food Price Index averaged 174.6 points in 2017, up 8.2 percent from 2016 and reaching the highest annual average since 2014.
The FAO Cereal Price Index remained broadly stable for the third consecutive month, with international wheat prices weakening while those of maize and rice firming up. The Index was 3.2 percent higher over 2017 than in 2016, while still 37 percent below its 2011 peak.
The FAO Vegetable Oil Price Index declined by 5.6 percent from November, as palm oil prices tumbled amid swelling stocks in Malaysia and Indonesia. That in turn pressured down soy oil quotations. Over 2017, the subindex ran 3 percent higher than the prior year.
The FAO Sugar Price Index also declined, marking a 4.1 percent drop from November due to seasonal factors and expectations of a large surplus in the year ahead. Sugar prices were 11.2 percent lower, on average, in 2017 than in 2016, due largely to a bumper harvest in Brazil, the world's leading producer.
The FAO Dairy Price Index declined 9.7 percent in December, with high export supplies and subdued demand weighing on the international prices of skim and whole milk powders as well as cheese and butter. Still, the subindex was 31.5 percent higher over the whole of 2017 than the previous year.
The FAO Meat Price Index slipped slightly in December, with strong supply pressuring international prices for bovine meat down. For the year, the subindex registered a 9 percent increase from its 2016 level.