A Little Girl With a Big Appetite and Even Bigger Temper Mother of an overweight child responds to viewers' comments and compassion.

LAND O' LAKES, Fla., Feb, 1, 2008  -- Since the story of Kayla Galo — a 4-year-old who at 105 pounds is twice the average weight for a child her age — was first posted on ABCNEWS.com Thursday, it has had enormous response from readers. You can read those comments by clicking on the "Comments" link on the right side of this page.

Many viewers and readers have concluded that Kayla has Prader-Willi Syndrome, an eating disorder often associated with behavioral problems. We wondered about that as well, but Kayla's mother, Luz Matos, tells us that Kayla has been tested for PWS and those tests were negative.

Matos wrote to ABCNEWS.com in response to viewers' comments and compassion. In it she says:

"Kayla has been tested from head to toe, from a [CT] scan of the head looking for a trigger of the pituitary gland, every blood test you can mention. [The doctors] tested her for Prader-Willi, thyroid, diabetes and anything you can imagine and all came out negative. Even her hemoglobin is OK. The last blood work was for a genetics disease and [it was] negative."

Matos signs her note on ABCNEWS.com "desperate seeking mom." You can read her full response by clicking on the "Comments" link. ABC News is trying to help connect Matos with specialists who can assist her.

Here is her story:

"No! Not that spoon!" screams 4-year-old Kayla Galo as she throws an epic tantrum at the kitchen table. "Oh my God — not like that! I don't want that there!"

What Kayla very clearly doesn't want is the bowl of soup her mother, Luz Matos, has prepared for lunch. Just shy of her fifth birthday, Kayla is 105 pounds, twice the average weight for a child her age.

"Mom, stop that! What's wrong with you?" she says forcefully, determined to have macaroni and cheese for lunch.

"I don't want any soup!" Kayla then shifts strategy and adds, "you're mad at me."

See more of Kayla's story Friday on "Nightline" at 11:35 p.m. ET

Matos has a distraught look on her face. She struggles to suppress her frustration.

"Eat it!" she says firmly, but with a tone that conveys a mother's love.

"No!" screams Kayla in a very angry voice.

"She gets what she gets," says Matos, explaining that doctors and nutritionists have counseled her to carefully control Kayla's food intake. "I'm not going to make another thing."

It is like this day and night in the Galo-Matos home here in Land O' Lakes, Fla., just north of Tampa. A constant battle of wills between a child obsessed with eating and a mother straining to cope with a behavioral problem that has defied experts.

Kayla has been overweight since she was a baby. At 18 months she began sneaking food out of the refrigerator. No one in her family has a problem with obesity, so it never occurred to Kayla's parents to limit her food intake. But by age 2 she weighed 52 pounds — twice the recommended weight.

ABC News first met Kayla a year ago when the family lived in Chicago. At that time Kayla weighed 95 pounds. Her mother had resorted to locking the refrigerator and hiding food.

Back then Matos thought she was gaining control of Kayla's ravenous appetite and her rage.

She was wrong.

At the kitchen table the standoff over the unwanted soup drags on. Kayla ups the ante, with a new series of attacks on her mother.

"I don't love you. You gave me a little bit. Stupid. Be quiet! Give me another treat or something."

At times it is hard to remember that these words are coming from a little girl who is not quite 5.

"When you finish the soup, I will give you the treat," says Kayla's mother.

Kayla takes a spoonful and swallows. The rage returns in an instant.

"It's just nasty," she says in a voice that is both screaming and pleading. "Give me treats, I don't have time for this!"

Matos struggles to hold her ground. Hovering in the background is Matos' bewildered mother and Kayla's grandmother.

"There have been times where I just want to pull out my hair and cry," says Matos. "I don't even know what to do."

There are tears in her eyes.

"I've been trying and trying and trying," she says. "We try to control her weight, we do exercise, she's a very active child and I don't know where this compulsiveness is coming from."

A year ago, after extensive testing, doctors in Chicago determined that there was nothing medically wrong with Kayla and that she was simply eating too much and getting too little exercise.

"I believe that Kayla has been rewarded with food," social worker Sandra Vieyra told ABC News last year, "and I believe that therefore, emotionally she likes her food and she wants more and more of it. … It's easier to prevent her tantrum than it is to really stay firm."

Kayla spots some snacks for her big brother's school lunch and demands some.

Matos goes to the car to hide the snacks in the trunk. While she is outside Kayla's tantrum continues. Her grandmother gives the girl her own lunch.

Kayla wins.

"No, you can't do this!" says Matos to her mother.

"She gave it to her so she could shut up," says Matos with exasperation, now frustrated by both her mother and her daughter. "I don't want to argue with my mother."

One of the reasons the family moved to Florida was so that Kayla could get exercise year round. They left behind a Chicago apartment for a modest home with a backyard and room to run. Matos works nights, her husband works days. Several times a week mother and daughter go to a children's gym for classes and free play.

As Kayla bounces and run and jumps with the instructors, Matos chats with the other mothers, hoping to pick up pointers.

"You have to stand firm," says Tina Danielson. Her 4-year-old daughter Jordan weighs 42 pounds, 60 pounds less than Kayla. "You can't give in to tantrums."

But with Kayla that is a constant challenge.

At the Publix supermarket, Matos tries to choose foods carefully.

"I don't like that!" screams Kayla as her mother selects a healthy cheese. "Put it back! Put it back!"

When Matos picks up bottles of water and passes by the bottles of juice, Kayla gets furious: "I don't like that water!!!"

Then she hits her mother.

Since moving to Florida, Matos has tried to get more medical help — she has health insurance — but when she called to make an appointment with a specialist in December, she was told the first available date is eight months away — in July.

"I told them 'she's 4 feet tall and she's weighing 105, she's going to be 5 years old in a couple of weeks, can't you do something to get me in sooner?'" Matos says they told her, "'I'm sorry ma'am, it's according [to] the child's health priority.'"

We met with Marie Graf, a pediatric dietitian at St. Joseph's Children's Hospital in Tampa. She has now offered to meet with Kayla.

"My reaction as a practitioner," says Graf, "is that Kayla's at the highest risk for these adult diseases that we're seeing younger and younger in childhood, like high cholesterol, fatty liver, high blood pressure and diabetes. I feel very worried for her and her family. And I also just want to ensure that all the medical reasons that she might be at an extremely high weight have been ruled out."

Graf says children as overweight as Kayla are becoming more and more common.

"I am seeing more and more over time," she says, "and it just seems to be getting younger even infants are coming in very overweight. Often times it's due to the family situation and not the child."

Graf says it is very important that families eat meals together, without TV or other distractions. That's what they do in the Galo-Matos home, but inevitably one parent is working. And inevitably Kayla dominates with her demands.

Back at the Matos home it's more of the same. "No! I said no! I don't like corn! Just put it back!"

Kayla's 10-year-old brother, Jaylen, sits patiently at the table.

"She hits me," he says with tears in his eyes. "She hits me."

Yet he still finds room to love his little sister. He has just one wish for her.

"To make her skinny. Make her the weight that she's supposed to be."

Matos knows that as the mother, most people will automatically blame her for Kayla's weight and her behavior. But she also knows, she's trying to be a good mother.

She's stumped.

"Got any suggestions?" she asks. "I don't know what else to do."