The U.S. Department of Agriculture's annual report on food security showed that those 691,000 children lived in homes where families had to eat non-balanced meals and low-cost food, or even skip meals because of a lack of money. The number of children struggling to feed themselves adequately rose 50 percent from 430,000 children in 2006.

Nearly 36.2 million children and adults struggled to put proper food on the table in 2007, according to the report, up slightly from 35.5 million in 2006.

Of the 36.2 million, nearly a third were not able to eat what was deemed a proper meal.

The other two-thirds -- 11.9 million people -- changed their eating habits by eating low-cost foods, participated in federal food and nutrition assistance programs, ate less varied diets or obtained emergency food from pantries or emergency kitchens, according to the report. That number is up more than 40 percent since 2000.

The prevalence and number of families struggling to eat properly differs drastically from state to state. Mississippi, New Mexico, Texas and Arkansas have the highest rates of prevalent food insecurity.

In Alaska and Iowa, there was a 3.7 percent increase in families struggling to eat adequately, the highest growth among the states over the past nine years, according to the report.

Florida and Hawaii both saw a decrease of about 4 percent in the number of families struggling to feed themselves.

Families headed by single mothers, Hispanic families, African-American families and households with incomes below the poverty line struggled the most, according to the report.