Parents who pack salami and ham sandwiches in their kids’ lunch boxes may be raising their risk of cancer. The World Cancer Research Fund (WCRF) says convincing evidence shows that processed meats, which include salami, ham, bacon, and hot dogs, raise the risk of bowel cancer.

Experts at the WCRF suggest that instead of using processed meats, parents choose low-fat cheese, poultry, fish, hummus or small amounts of lean meat as sandwich fillings. In fact, they recommend that children not eat any processed meat because they help form unhealthy habits. Including sandwich fillers such as ham and salami could mean children get into habits that increase their risk of developing cancer late in life, according to the WCRF.

“If children have processed meat in their lunch every day then over the course of a school year they will be eating quite a lot of it. It is better if children learn to view processed meat as an occasional treat if it is eaten at all,” said Marni Craze, Children’s Education Manager for WCRF.

“Putting ham or high calorie snacks in your children’s sandwich might seem like a convenient option, particularly for parents who do not have a lot of time to prepare their child’s lunchbox,” Craze said. “But packed lunches are a part of a child’s diet that is relatively easy to control and it does not have to take too much time or effort to prepare a healthy lunch.

“For example, putting some salad into a sandwich will count towards the five portions of fruits and vegetables children should be eating every day,” she said. “And a small fruit juice instead of a fizzy drink will also give a portion. Also, chicken that has not been processed, fish, hummus or low-fat cheese are easy and quick alternatives.”

The WCRF recommends limiting total meat intake to about 70 grams or the equivalent of three slices of bacon a week.