Outnumbered, outfoxed and outraged, Senate Democrats were maneuvered yesterday by a sweetly smiling Sen. Jesse A. Helms (R-N.C.) into accepting a $200 million cut in foreign aid in order to rescue $200 million for child nutrition programs.

The Democrats, who have had more than a little trouble getting their budget act together, were finally geared up for a counteroffensive against President Reagan's proposed $1.6 billion cut in nutrition programs when Helms, the liberals' nemesis, beat them to the punch.

Gaining the floor at the start of the second day of Senate debate on the budget cuts, Helms proposed that $200 million be switched from foreign aid to school lunches and other children's feeding programs, which Democrats have made one of their leading causes in the propoganda war over budget cuts.

"All I'm trying to do is take some money from foreign aid and give it to the schoolchildren of America," said Helms, adding that he also intended, a chairman of the Senate Agriculture Committee, to transfer $100 million from the Food for Peace program to child nutrition, for a total restoration of $300 million to nutrition programs.

With that, Helms triggered the loudest, most rancorous and emotional outburst that the Senate has seen since the Republicans took control earlier this year for the first time in a quarter century.

The problem was that the Democrats wanted to add money for child nutrition, but not at the expense of foreign aid -- but didn't have the votes to prevent it once the Republicans gained the upper hand.

"It's hogwash," exclaimed Sen. Edward M. Kennedy (D-Mass.), to say that the United States has to "take away a crust of bread from starving children" in foreign countries in order to feed its own schoolchildren.

"I think it's a sad day, indeed, when we pit the poorest starving children of the world . . . against American children" and respond with "a pious answer that we're going to do something about the budget," added Kennedy, pounding his fist on his desk and flailing at the air with his arms.

As Kennedy pounded away, Helms, clearly enjoying himself, pounded back in a kind of tom-tom response from his desk across the chamber. In the midst of it all, the gallery above Kennedy was filled with members of a visiting choir, decked out in blue and gold robes, looking as though they might break out at any moment in requiem for the beleaguered Democrats.

Kennedy succeeded in winning separate votes on the foreign aid cut and the school lunch add-on, but lost in the acutal votes on both.

The extra school lunch money was approved, 87 to 9, with seven Republicans joining Sens. William Proxmire (D-Wis.) and Harry F. Byrd Jr. (Ind-Va.) in voting no. The foreign aid cut was approved, 70 to 26, with most Democrats voting for the cut.

Among Democrats, 24 voted for the cut while 16 voted against it. Most Republicans supported the the foreign aid reduction, which came on top of a cut of roughly $1 billion that Reagan proposed and the Senate Budget Committee approved.

Among Washingon-area senators, only Byrd voted against the extra money for school lunches. On foreign aid, the Virginia senators voted to cut, while the Maryland senators voted against cutting with Sen. Charles McC. Mathias Jr. (R-Md.) helping lead the unsuccessful opposition to any further foreign aid reductions.

Nursing their wounds after their brush with Helms, the Democrats regrouped and came back later in the day with a proposal from Sen. James R. Sasser (D-Tenn.) to add another $200 million to nutrition programs. It failed by a predictable party-line vote of 35 to 54.

In between the two nutrition votes, the Democrats made another stab at trying to restore some of the cuts that Reagan proposed in health programs for veterans, this time by shifting $104 million from foreign aid to veterans programs. They lost on this one too, 44 to 48, just as they did Thursday in two previous efforts to come to the aid of the veterans.

It was the Democrats' plan to trade off foreign aid for veterans that prompted the Republicans to try a preemptive strike for the nutrition programs.

After a little plotting by Budget Committee Chairman Pete V. Domenici (R-N.M.) with Helms and other Republicans Thursday night, the Republicans decided they would use their turn at bat for amendments in the morning to ambush the Democrats.

The Democrats made no effort to hide their pain, and Helms, in his best aw-shucks manner, gently rubbed salt in the wounds. As Winston Churchill once said, drawled Helms after the Democrats had been crying out for nearly an hour about hungry children at home and abroad, "there's nothing more satisfying than to be shot at and missed."

Bristling with anger, Sen. Donald W. Riegle Jr. (D-Mich.) protested that Helms' proposal would still leave "tens of thousands" of schoolchildren without lunch, and exclaimed, "I really feel you have been shooting at the schoolchildren of America and you have not missed."

Wading into the midst of the debate, Sen. Bob Dole (R-Kan.) couldn't resist claiming that the Senate was "hearing the same tired liberal voices that got us into this [budget] mess in the first place."

That, in turn, was too much for Kennedy. "This is one young Democrat who is proud to be associated with it," he shouted, presumably meaning the liberal legacy.

Even the normally soft-voiced Senate Majority Leader Howard H. Baker Jr. (R-Tenn.) rose to the occasion, proclaiming loudly that "the poor are being cruelly used in order to try to restore to this budget money for programs that have failed."

Other Republicans chimed in to argue that Reagan would keep feeding programs for the poor, while requiring others to pay their own way.

Not so, protested Kennedy. Reagan's cuts anticipate that children from families with incomes exceeding $15,000 a year will be cut off the lunch programs, he claimed, asking sarcastically whether children from families earning little more than $15,000 annually can really be considered "rich kids."

Asked after the vote whether he was indeed trying to preempt the Democrats, Helms said, "I'll have to confess, yes." Asked then why he was smiling, Helms responded:

"Because it worked."