Soon-expected U.S. Department of Agriculture updated nutrition standards for snack foods and beverages could help trim students’ waistlines, boost fruit and vegetable consumption and improve school revenue, a new study claims.

Replacing a candy bar with an apple could have a big effect, according to the 172-page health assessment released by the Kids’ Safe & Healthful Foods Project and the Health Impact Project,

The study found that implementing strong snack and a la carte food and beverage policies meeting 2010 Dietary Guidelines for Americans will cut students’ access to (and consumption of) unhealthy foods and beverages.

“The evidence would suggest that when it does get published, and finalized and implemented, that it stands to have a very positive impact on children’s health without having a negative impact on school districts’ budgets,” said Jessica Donze Black, director of the Kids’ Safe & Healthful Foods Project.

Both the Health Impact Project and the Kids’ Safe & Healthful Foods Project are joint efforts of the Pew Charitable Trusts and the Robert Wood Johnson Foundation,

The study found that schools and districts with strong nutrition standards for snack and a la carte foods and beverages did not experience a decrease in revenue overall when they exercised tighter control on school snacks.

“In most instances, school foodservice revenues increased due to higher participation in school meal programs,” according to the study.

The study recommends that USDA establish nutrition standards for all foods sold regularly at schools and that those standards include age-appropriate calorie limits and restrictions on sugar and fat for snack food sold in schools. The study also recommends that the USDA provide technical assistance and training to school officials. In addition, the USDA should provide clear guidance on how the terms “infrequent,” “school day,” and “school campus,” as included in the Healthy, Hunger-Free Kids Act, should be addressed.

Donze Black said it was likely that USDA will at least propose limits on calories, fat, sodium or sugar and seek comments.

She said the USDA should support sales of foods that kids need to eat more of, including fruits and vegetables, low-fat dairy and other healthy foods.

While the USDA rule on competitive food has been expected for some time and is a requirement of the Healthy Hunger Free Kids Act of 2010, Lorelei DiSogra, vice president of nutrition and health for the Washington, D.C.-based United Fresh Produce Association, said it is unclear when the agency will issue the proposed regulation.

DiSogra said some nutrition advocates expect the proposed rule will be issued before November, while others are skeptical that the White House will move before the election and risk negative publicity.

DiSogra said the new rule could provide a boost to the industry.

“It is going to open up new sales marketing opportunities for fresh and fresh cut fruits and vegetables because it has to follow the Dietary Guidelines and improve the school food environment,’ she said. “I think it is going to be very important for fresh produce.”

Donze Black said it is “imperative” that the USDA moves on the regulation as quickly as possible.

“What the study shows is that we can’t afford to wait given the health crisis we are in with children, and school districts will be able to afford to make the changes,” she said.