I use to be one of those "genetics" posters about being overweight, but I started to count calories, exersize and dropped like 80 pounds. Most people don't understand what they're eating, why they're eating it, or even the composition of a calorie. You have people who are programmed to eat certain things and don't have the conditioning to break fee. They will just shovel food down without thinking - Even some of their food knowledge is so arcane and broken. I had one broad get pissy at me for eating burger king(after I lost 80 pounds) and couldn't understand Calories in-Calories out when I got a whopper with no mayo and she got one of those fried chicken strip salads with extra dressing(the full fat ones).
These people really think that if they eat "healthy" that their magic body will come.