The Grocery Manufacturers of America yesterday accused the Federal Trade Commission of creating a "national diet" that could exclude fruits, vegetables and "even mothr's milk" by proposing to ban television advertising aimed at young children.

Speaking first at the opening day of five weeks of hearings here on "Kidvid" children's advertising -- GMA spokesman Dr. Robert W. Harkins said "advocates of the proposed rule are trying to limit the marketing to children of foods with significant sugar content. However, in their zeal, they have neglected to evaluate the effect the rule would have on the diet."

Harkins attacked proposals to limit television advertising of foods with high sugar content, claiming that such items as celery (21 percent sugar content), yogurt (42 percent), apples (79 percent), mother's milk (49 percent) and peas (36 percent) world not be permitted in ads under such a plan.

But Peggy Charren, president of Action for Children's Television, a Boston-based consumer group, attacked most TV ads aimed at children as "deceptive."

Witnesses for the American Broadcasting Co. said an FTC proposal to ban some advertising aimed at children was "flawed" and would result in a drop in the quality and relevance of children's programming.

ABC-TV vice president for social research Melvin Goldberg testified before hearing officer Morton Needelman that the FTC staff report contained no data relevant to the long-term aggregate effects of television advertising on children.

Alfred Schneider, another ABC vice president claimed that ABC's system of reviewing television advertising directed toward children was effective.

Earlier, White House consumer affairs advisers Esther Paterson praised ABC for its decision last month to cut back commercials 20 percent during weekend children's programming, and to more clearly separate program material from selling. "ABC has shown it is not impervious to the concerns of parents and educators," she wrote.

Peterson warned ABC, however, that she hoped the new policy would not result in the droopping of more responsible ads, thus increasing the proportion of ads for "sweets and toys."

As Schneider was about to extol the virtues of a special children's show entitled "Fireworks," a small electrical fire broke out in the hearing room, briefly delaying prooceedings.