A new Library of Congress study contends that President Carter's proposal to limit deductions for business lunches would not hurt the restaurant industry, as some critics have claimed.

The study, made public by Sen. Edward M. Kennedy (D-Mass.), argues that any adverse impact on restaurant jobs would be totally offset by the extra economic stimulus stemming from Carter's general taxcut program.

Moreover, it predicted, even if Carter's business-lunch proposal is enacted, the restaurant industry still would continue to grow at a faster rate than the rest of the economy --pace.

The study was designed to rebut claims by industry spokesmen that the Carter proposal would increase unemployment among waiters, cooks and other restaurant and hotel workers.

Under present law, companies may claim deductions for the full cost of business meals. Carter wants to trim this to 50 per cent of the restaurant tab, and also deny present writeoffs for other forms of entertainment.

The restaurant industry made similar claims in 1960, when Congress was considering a bill that would tighten record keeping procedures for business meals. The measure ultimately passed, with no adverse effects.

The Treasury has argued repeatedly that the Carter restriction would not create serious unemployment in the restaurant industry, but has revised its estimates several times.