LOS ANGELES (REUTERS) - McDonald's Corp in January will cut eight food items and reduce the number of so-called Extra Value Meals on its US menus in a bid to speed up service and bolster sales, said Mike Andres, the company's US president.

The world's biggest fast-food chain, which hasn't had a monthly gain in sales at established US restaurants since October 2013, also will start shortening its food ingredient lists as consumers demand simpler, more natural food.

The company is testing its slimmed-down menus in six markets, including Bakersfield, California, and Knoxville, Tennessee, a spokesman said.

The simplified menu boards offer one Quarter Pounder with Cheese hamburger compared with four on the regular menu, one Premium Chicken sandwich versus three, and one Snack Wrap versus three.

Andres said McDonald's is not finished tweaking menus.

"There's more to come," Andres said on a conference call with investors. "We don't need to have a big menu board to offer variety."

The menu changes come as McDonald's plans to roll out its new "Create Your Taste" sandwich customisation program to three US markets by the third quarter of next year.

McDonald's is hoping that by giving customers a choice of sandwich toppings it will help the chain to better compete with Subway and Chipotle Mexican Grill Inc, which allow diners to build their meals ingredient-by-ingredient.

McDonald's is also working to win back mothers and young diners, who increasingly want food that is fresh and minimally processed.

Simplifying ingredients in McDonald's food is an enormous task, "but we have to get started," said Andres, who offered a glimpse into how the company is rethinking its recipes.

Busy McDonald's operators don't keep food in storage for very long, he said.

"Why do we have to have preservatives in our food? We probably don't."