Chicken has long been touted as a healthy animal protein source, especially skinless and boneless chicken breast. However, new studies have shown that the healthiness of chicken breast can vary massively from piece to piece.

The problem is noticeable when you look at a chicken breast. It will look fine, apart from tiny white lines on the surface of the meat, and it’s these white lines that are causing concern.

According to a study published in Poultry Science magazine, packaged chicken breasts have been appearing with these small white stripes on simply because chickens are being grown ever-larger these days.

The lines are called ‘white striations’, and they come from birds that have a large fat content. Poultry companies want to grow larger chickens to sell at a cheaper price, and some farmers have been caught overfeeding their birds or adding growth hormones to their diets in order to bulk them up. This is a consequence of the push for growing larger birds to meet demand, and it turns out it could have a knock-on effect for our own battle against weight gain.

A study was performed to see how bad the extra fat content of the chicken breasts could be for those who ate the striated meat. The researchers found that the worst examples of striated meat contained over 200 percent more fat content than a breast with little or no striping. They also found that the protein content of the striated meat is decreased in moderate to severe cases.

Another study by the University of Arkansas and Texas A&M concluded that the white  striping problem has become worse in recent years, and they found it in a whopping 96% of the 285 birds they tested.

Researchers also found that the striations negatively impacts the quality of the meat, and results in chicken that is tougher and absorbs marinades less easily.

On the flip side, a spokesman for the National Chicken Council says that white striping only affects a small percentage of chicken meat, and that it doesn’t create any health, food safety or animal welfare concerns.

Consumers can tell the bad meat from the good simply by inspecting the chicken breast closely. A small amount of striping is OK, but if there’s a lot, it’s best to look for another piece.