WASHINGTON — Four Corn Refiners Association member companies filed a countersuit on Sept. 4 in a U.S. District Court in Los Angeles alleging that the Sugar Association is deceiving consumers into believing that processed sugar is safer and more healthful than high-fructose corn syrup.

In the still-pending original lawsuit, the Sugar Association alleges the C.R.A. made false and misleading advertising about HFCS. C.R.A. member companies Archer Daniels Midland Co., Cargill, Ingredion Inc. and Tate & Lyle Ingredients Americas, Inc. filed the countersuit.

“The Sugar Association has worked to perpetuate the myth that high-fructose corn syrup uniquely contributes to obesity and other health problems, preying on consumers’ food fears and diverting attention from the real issue — that Americans should reduce their consumption of all added sugars and calories in general,” the countersuit said.

Adam Fox, a partner with Squire Sanders, which is based in Los Angeles and co-lead counsel for the Sugar Association and other plaintiffs in the lawsuit, said peer-reviewed, published studies have found health differences between HFCS and sugar.

“The evidence plainly shows that sugar and HFCS are not the same,” he said. “They are molecularly different. They are functionally different. The body can tell the difference.”

Among the evidence presented in the countersuit, two items occurred this year.

The January issue of the Sugar Association’s “The Sugar Packet” featured commentary from John McElligott, M.D., and a Fellow of the American College of Physicians.

“In my opinion, high-fructose corn syrup is one of the worst things you can put in your body,” he said. “Some have called it the ‘crack cocaine’ of all sweeteners. I agree.”

A May 24 news release from The Sugar Association said sucrose is molecularly different than HFCS because of a naturally occurring bond between its fructose and glucose molecules. This bond must be broken as part of the metabolism of sucrose. HFCS does not have the bond.

According to the countersuit, the bond in the sucrose is not meaningful to human health.

Mr. Fox said there is scientific debate as to whether the bond is meaningful to human health.

Sugar (sucrose) is 50% fructose and 50% glucose. According to the countersuit, high-fructose corn syrup drew its name from the fact it has a higher fructose concentration than regular corn syrup. HFCS generally is traded in the two forms of HFCS 55, which is 55% fructose, and HFCS 42, which is 42% fructose.

The countersuit gives opinions from those who believe HFCS is nutritionally equivalent to sugar. For example, the Academy of Nutrition and Dietetics (formerly the American Dietetic Association) has said HFCS is nutritionally equivalent to sucrose in that both sweeteners contain 4 calories per gram, consist of about equal parts fructose and glucose and are indistinguishable once absorbed into the blood stream. The American Medical Association has concluded it appears unlikely that HFCS contributes more to obesity or other conditions than sucrose.

Since the A.M.A. came to that conclusion in 2008, more studies have found health differences between HFCS and sugar, Mr. Fox said.

He pointed to a study appearing in the journal Metabolism this year. Forty men and women consumed 24 oz of HFCS-sweetened beverages or sucrose-sweetened beverages in a randomized crossover design trial. Compared with sucrose, HFCS led to greater fructose systemic exposure and significantly different acute metabolic effects.

Audrae Erickson, president of the C.R.A., said the study did not compare HFCS to sugar made from cane and beets and it did not use real-life diets as a model.

The original lawsuit, filed on April 22, 2011, said the C.R.A. claim that HFCS is corn sugar is false and misleading. The plaintiffs cited Internet advertising, exhibitions at professional organizations, television commercials, print advertisements and the web site www.sweetsurprise.com.

The Food and Drug Administration on May 30, 2012, denied a C.R.A. petition that corn sugar be allowed as a common or usual name for HFCS. Since then, the C.R.A. has stopped referring to HFCS as corn sugar.

In reference to the countersuit, Mr. Fox said, “There is really nothing in here that is surprising at all. This is par for the course for ADM and Cargill and the other corn refiners.

“They have essentially taken every step possible to not face the facts about HFCS. At first, they blamed the name and tried to change the name to corn sugar, and the F.D.A. rejected that. They can’t blame the name anymore.”