ROYAL OAK, Mich. (AP) _ Larry Coker is so excited about losing 575 pounds in 18 months he plans to celebrate with a banquet.

Not the kind of spread one might expect, however.

''We'll have lots of salad and carrots and he wants a fruit bowl,'' said his mother, Barbara Coker.

Coker, who went from 750 to 175 pounds, said he used to eat four quarter- pound hamburgers, a bag of corn chips and two liters of pop as a nighttime snack.

''I used to love to eat a half-pot of macaroni and cheese at one sitting,'' said Coker, 20.

While a student at Royal Oak Dondero High School, he used the freight elevator to get to classes on the second floor. At his peak weight, he owned only one T-shirt that fit.

Eating was a way of dealing with personal problems, including the divorce of his parents, Coker said.

''Whenever I was nervous, I'd eat. It was easier than talking about my feelings,'' he said.

On Jan. 5, 1988, he decided to turn things around. Tired of having to sit in a broken chair and having his brother put on his socks and shoes, he began a medically supervised diet he put together himself.

His caloric intake is down from 6,000 daily to about 650. A typical dinner is five ounces of poultry, unbuttered green beans and a salad.

''I also try to eat an apple before each meal and drink eight glasses of water a day,'' he said.

He often roller skates five miles.

Nutrition experts caution rapid weight loss poses some health hazards.

''He lost the weight very fast, which is dangerous,'' said Catherine Jen, associate professor of nutrition at Wayne State University in Detroit. ''If you lose more than two pounds a week, you run a medical risk of losing body protein and muscle mass.''

The loss of muscle mass could result in a mineral imbalance, which could cause cardiovascular problems.

Also, the lower muscle mass requires a much smaller caloric intake, making later weight gain a strong possibility, she said.

Coker said he had other concerns when he started his diet. At first, he had hoped to slim down to 260 pounds ''so I could fit into some decent jeans and shirts. Then I thought, 'Why quit there?'''

''I just wanted to be normal,'' he said.