Chickens raised in factory farms today have been bred and genetically manipulated to gain weight as fast as possible on a minimum of feed. Every effort has been made to enhance what is called the feed-conversion ratio, which measures how much weight the chickens gain from the food they eat.
The average breast of an eight-week-old chicken today is SEVEN TIMES heavier than it was 25 years ago. In fact, by the age of six weeks, 90% of broiler chickens can no longer walk because they've become so obese. (I'm not going to even touch on the ethical issue here, but there is obviously a huge one!)
In one lengthy study, men and women eating even a single ounce of chicken a day (equivalent of 2 chicken nuggets) had a significantly greater weight gain than those who consumed no chicken at all. Chicken has this reputation for being "low-fat". I used to think they were low-fat too! While training for Ms. Louisiana Fitness, all I consumed was chicken (and fish and tuna)! Based on the USDA Database: a century ago, a single serving of chicken may have had about 16 fat calories, now one serving has about 200 calories of fat!! We went from 2 grams per serving to more than 20 grams per serving a day! Therefore, it's ten times more fat calories, in fact, TWO TO THREE TIMES MORE CALORIES FROM FAT THAN FROM PROTEIN! The beef industry loves bragging about that, especially having less saturated fat than chicken. And that's because of our industrial food system that demanded these birds to grow to maximum slaughter weight in the minimum amount of time, to reduce feed cost, which is the exact mechanism by which a chicken, more than any other animal product, is associated with weight gain over time.