By Lucia Mutikani WASHINGTON (Reuters) - The U.S. economy grew far less than expected in the second quarter as inventories fell for the first time since 2011, but a surge in consumer spending pointed to underlying strength. Gross domestic product increased at a 1.2 percent annual rate after rising by a downwardly revised 0.8 percent pace in the first quarter, the Commerce Department said on Friday. Economists polled by Reuters had forecast GDP growth rising at a 2.6 percent rate in the last quarter. While the drop in inventories weighed on GDP growth last quarter, that is likely to provide a boost to output for the rest of the year. GDP growth in the first quarter of 2015 was revised sharply higher to a 2.0 percent rate from the previously reported 0.6 percent pace. Consumer spending was responsible for almost all of the rebound in GDP growth in the second quarter.