Actress Mary Dimino poses with her pre-weight loss size 28 jacket.

As the number of obese Americans climbs to frightening levels, the quest for answers is becoming more urgent. Obesity experts have a growing and sobering awareness of the complex human puzzle that is driving this epidemic and creating so much personal pain in a society that worships "thin." Is it genes? Is it metabolism? Is it stress, evolution or the lack of willpower?\~ Why can't the brain control hunger?

Fat: What No One is Telling You gives viewers a window into the intense human dramas that exist inside people who have been labeled obese, and the difficulties they encounter in solving their weight problems. The program , narrated by Meredith Vieria ( The Today Show ), airs Wednesday, April 11 at 9/8 p.m. CT on KET1.

Even the most disciplined effort to lose weight is beyond the abilities of many people -- not because of weakness, but because of the complex mix of environmental factors and biology that make it a lot easier to gain weight than to lose it. As the program opens, Mary sweat s through one of her daily three-hour gym sessions on the treadmill. Acknowledging that it's a lot of exercise, she explains, "I have to work just as hard, even harder, just to maint ain this level of chubbiness." Like many people who struggle with weight control, Mary has persistent fat cells in her body that were add ed during years of overeating. Now the weight may come off, but the cells remain, and they constantly cry out for more calories and defy Mary's willpower.

Fat: What No One is Telling You includes many personal stories like Mary's, along with interviews with obesity experts in the medical and academic fields. The program also explains how eating habits are established and suggests ways to combat childhood obesity.

F at : What No One is Telling You is produced by Twin Cities Public Television .