DETROIT (Good Medical) – Beer drinkers can no longer claim happy ignorance.

Beginning next month, Bud Light's packs will carry prominent labels stating the calories and ingredients of the beer, as well as the amount of fat, carbohydrate and protein in one serving.

Bud Light is probably the first of many to make the move. Labels are not legally required, but leading beer manufacturers agreed in 2016 to voluntarily release nutritional information on their products by 2020.

Many brands, including Corona Light, Guinness, Heineken and Coors Light, already have calories and other nutritional information on their bottles or packaging. But it's in small print, or hidden at the bottom of the six pack, and the ingredients are not listed.

Bud Light has opted for a large black and white label, similar to that required by the US Food and Drug Administration on packaged foods. At the top, Bud Light lists its four ingredients: water, barley, rice and hops. Below, it shows the calories in a 12 ounce bottle or can (110) and other facts. For example, Bud Light contains 2% of the recommended daily amount of carbohydrates.

"We want to be transparent and give people what they're used to seeing," said Andy Goeler, vice president of marketing for Bud Light.

Individual Bud Light bottles and cans will not have the full label, but some nutritional information will continue to be printed in small print.

According to Goeler, the brand's research shows that young drinkers, in particular, want to know what's in their beer.

"They grew up in harmony with the ingredients," he said.

Goeler said it did not know when other brands owned by Bud Light's parent company, Anheuser-Busch, including Michelob and Stella Artois, would adopt larger nutrition labels.

But the question is: will such labels make a difference in consumer choices? At least one study suggests that they will not do it.

Researchers from Cornell University and Louisiana State University traced what was happening when clients received menus with a number of calories. It was found that calorie-conscious customers ordered lower calorie inputs and inputs, but the calorie count had little impact on beverage and dessert orders.

John Cawley, professor of economics at Cornell and one of the authors of the study, said that clients seemed to respond the most to information they did not already know. They were probably surprised by the number of calories in some out-of-work, for example, but already knew the general range for a glass of beer or wine.

Cawley said it was said that light beer would be the most promising in terms of ingredients and nutritional information. Budweiser, Bud Light's brother, consumes 35 more calories and four grams of extra carbohydrates, according to the brand's website.

In the end, the biggest changes could come from the manufacturers themselves, not consumers, Cawley said. Since nutrition labels became mandatory in the early 1990s, companies compete for a healthier look or eliminate unwanted ingredients such as trans fatty acids.

"It's actually the biggest public health victory of all," said Cawley.