SAN DIEGO -- Scripps Clinic in San Diego wants to find out whether one of the oldest fad diets in America, the Grapefruit Diet, actually works.

Researchers believe something in grapefruit can help people lose weight and moderately overweight San Diegans are being asked to put the citrus fruit to the test, 10News reported.

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"There have been very interesting scientific studies now showing that there are parts of grapefruit that actually contribute to weight loss," Scripps diet expert Dr. Ken Fujioka said.

Fujioka said that they are studying the fruits' membrane and said it may contain the active ingredient that aids in weight loss.

"This membrane may in fact have the compound that produces all the good things ... like weight loss," Fujoika said.

He believes there is a compound in grapefruit that interacts with the liver to lower cholesterol and helps regulate insulin. However, too much insulin can cause weight gain.

"We don't know if its the grapefruit, grapefruit juice, or a particular part of the grapefruit an extract called nerignin," he said.

Fujioka said study participants will be divided into three groups. One group will eat half a grapefruit three times a day. Another group will drink eight ounces of grapefruit juice daily. A third group will take a grapefruit extract. And a fourth group will take a placebo.

"If it works, obviously, grapefruit will become a standard part of the American diet," Fujioka said.

Ethan Consolvo is taking part in the study.

Consolvo's cholesterol has been climbing and so has his weight in the past couple years.

"My cholesterol is pretty bad," he told 10News.

Consolvo will eat half a grapefruit with every meal, three times a day.

Consolvo hopes his diet of grapefruit will produce noticeable results.

"Hopefully, I'll lose 30 pounds and have my cholesterol at least under 200," he said.

If you would like to enroll in the grapefruit diet study, call Scripps Clinic at (858) 794-1247 or visit their Web site.

Study participants must be at least 18-years-old and moderately overweight. Patients must not be taking cholesterol medications, anti-depressants or weight loss medications or be diabetic.