Why is this source not reliable? Is there any bias in it?

Home-cooked food is healthier than fast food. According to a recent study by the Palo Alto Medical Foundation, fast food burgers have on average 71 calories per ounce compared to homemade burgers that contains 67 calories per ounce. That means that a fast food quarter pound burger (4 oz.), has sixteen more calories than the same burger made at home. Those added calories could lead to weight gain, which can be bad for one’s health. In addition, in a 2005 study, Dr. Harold Haines states “people who eat fast food meals more than twice a week gain about 9.92 pounds and are more likely to get diabetes than people who eat home cooked meals (2).” The more fast food you eat, the more overweight you will be, and the more likely it is that you will have health problems like heart disease, or diabetes which can prevent you from living an enjoyable and long life with your loved ones.