In a move sure to have its competitors scrambling to keep up, Beech-Nut Baby Foods announced today that it has taken the sugar out of all but one of its baby food products.

According to company chairman Fank Nicholas, babies consume an average of 8.2 pounds of sugar from commercially prepared baby food in their first 12 months.

Health professionals have long argued that baby food should not be made to satisfy the taste buds of adults, but to meet the nutritional needs of babies. Excessive consumption of sugar, which offers no nutritional benefits other than energy, can lead to tooth decay, obesity and other problems.

Nutritionists generally approved of Beech-Nut's action. Michael Jacobson, director of the Center for Science in the Public Interest, said the action "represents an additional cleansing of commercial baby foods."

Food and Drug Commissioner Donald Kennedy said, "Any marginal effort to eliminate sugar is fine."

About 2 1/2 years ago, Beech-Nut, which had 13 to 15 percent of the $480 million baby food market in 1978, was the first to announce the elimination of salt and the reduction of added sugar in its products.

That prompted Gerber, which dominates the baby food market with a 70 percent share, and Heinz to remove salt from and reduce the sugar content in their products. Last week Gerber announced that it will take the sugar out of many of its products "during this current growing season."

That means sugarless products will begin to appear in the stores in the next six to 18 months. Gerber manufactures 150 products; 26 of them - desserts, teething biscuits and bany cereal with fruit - will continue to contain sugar.

A Heinz spokesman said the company "will continue to consider" the possibility of achieving further redcutions in sugar. Thirty-four of its 108 productions contain sugar.

All but on e of Beech-Nut's 120 products now on store shelves contain no added sugar. In order to make their entire line (with the exception of a cereal-formula-fruit product, Cera-meal) sugar-free, Beech-Nut discontinued two dessert products. Other items have been reformulated so that some are now sweetened with natural fruit concentrates.

Since 1977, the added sugar content of baby foods has not exceeded 9 percent.

Sales of commercially prepared baby foods declined between 1966 and 1976. This paralleled the drop in the birth rate, and signaled a reversal in the trend of starting babies on solid food as young as possible and a return to home preparation of baby food in order to avoid additives, salt and sugar. According to Nicholas, the decline in baby food sales began to level off in 1976 and the number of births in this country began to rise. Industry-wide, sales of baby food are now up 5 percent.