Costa wasn't just overeating, she was out of control.
"I used to probably have a pint of ice cream almost every other night, if not more than that," she said. "Not my proudest moments."
Aside from a pint of ice cream, Costa said she would also devour wings and waffle fries smothered in cheese and gravy.
"That meal alone was probably around 6,000 calories, if not more," she said.
By age 22, Costa tipped the scales at 316 pounds, and then decided to shed the weight in the most public way possible, on the reality TV show, The Biggest Loser.
On the show, she lost an astonishing 155 pounds, a transformation that landed her on the cover of magazines, such as OK! and Good Housekeeping. But when some of the weight started to creep back, she realized it wasn't just her body she was battling, it was her mind.
"Now it's not about willpower, it's about -- there might be something wrong up here," she said, pointing to her head.
Dr. Pamela Peeke, a nutrition and fitness expert, said Costa is not alone. Although some doctors dispute it, Peeke believes emerging research is evidence that food addiction is real.
And it just might be playing into this country's obesity epidemic. According to the Centers for Disease Control, more than one-third of American adults are now classified as either overweight or obese, and obesity kills more Americans every year than AIDS, all cancers and all accidents combined.
In her new book, The Hunger Fix, Peeke argued that for some people, food can be as addictive as cocaine with some experiencing cravings, binging and withdrawal.
"It's mixture of what we call the hyper-palatable ingredients and these are uber-rewarding to the reward system," she said. "In the brain, organically in the reward system, you're secreting lots of that wonderful pleasure reward brain chemical called dopamine, and it's coming out, and it's just giving you that fantastic feeling of, 'Wow, this is wonderful'... which is why my patients tell me, 'I need a hit.'"
For compulsive eaters, like Tara Costa, recognizing her addiction was like a thunderclap to the brain.
"[It] makes me feel good that, guess what, I'm not crazy," Costa said. "There's science now behind this that can help people."
In The Hunger Fix, Peeke offers a prescription to get food addicts on the road to detox, rehab and recovery. She calls it the three "M's": Mind, Mouth, Muscle. By focusing on the three "M's," Dr. Peeke believes people can re-train their brains.
Step one: Strengthen the mind. Peeke said people should identify the snacks they crave the most and then use transcendental meditation to reduce the urges.
"This is not a New Age moment," she said. "This is hardcore neuroscience. You activate that brain CEO when you do meditation, and by doing so, guess what, you're powering up the brain to be able to stay vigilant."
Step two: Trick the mouth. Peeke said there are ways we can replace our unhealthy "food fixes" with foods that are just as delicious but are whole, natural foods. Instead of reaching for the ice cream, Peeke said people should try a chocolate, cherry and almond protein smoothie, but instead of a protein bar, try a banana with peanut butter and instead of a cupcake, try a carrot muffin.
"So what I'm doing is I'm trying to make sure people understand they can get a healthy high without it having to be high-jacked in their reward system by all these sugary fatty, salty food combinations," she said.
Step three: Move your muscles. By working out regularly, Peeke said people can stave off cravings and reward their brains with endorphins instead of sugar.
"The new science now shows you actually increase the size of the brain, because you stimulate brain growth," she said, "It's called neurogenesis. Who doesn't want a bigger brain? I do."
"The second thing that happens is, when you do things like physical activity, you also induce changes in your genes, in your actual genes. It's a new science called epigenetics," she continued. "So what happens is if you actually have genes that -- place you at higher vulnerability for obesity, diabetes, heart disease, cancer. When you do physical activity, you dampen down that. You deactivate a certain percentage of those genes."
Tara Costa is in what Peeke calls "master recovery." Costa recently did something beyond her wildest imaginings -- she finished an ironman triathlon in Kona, Hawaii.
"No dream is impossible," she said. "Every day when I wake up I know that I'm going to be doing something that's going to build a bigger brain, going to run or ride a bike."
Costa said she will be a recovering food addict for the rest of her life, and while it is an uphill battle, just accepting her addiction is a victory.
"I wish I could be normal with it," she said. "I wish I could have one bite and be satisfied and that be it, but you know what, I have hope, I have hope that it will be OK."