(CBS Local) — What would happen if everyone in the United States switched to a vegan diet? Would the environment see an immediate change for the better? A new study has looked into the hypothetical eating shift and the results were not as positive as many would think.

Two researchers have put environmentalists’ claims that going vegan would stop climate change to the test in a simulation that looked at how a nation of 320 million vegans would affect greenhouse gas levels. Scientists found that the diet change would produce a major change to the problem locally.

The study, published in Proceedings of the National Academy of Sciences, estimates that a vegan America would reduce greenhouse gas emissions produced by agriculture by 28 percent.

Although animals reportedly make up nearly half of the agricultural emissions in the country, the team reports a vegan nation would potentially drop annual emissions from 623 million tons to 446 million tons per year.

There are a few catches to the study’s greener nation. The results found that not only would the overall impact to the planet be minor, the vegan diet would fail to meet the nutritional needs of Americans. Daily requirements for calcium, vitamins A and B-12, and key fatty acids couldn’t be met by the amount of crops being planted to support a whole country of vegans.

“With carefully balanced rations, you can meet all of your nutrient requirements with a vegetarian diet. But the types of foods that seem to do that, we don’t currently produce in sufficient quantities to make it a sustainable diet for the entire population,” lead author Robin White said, via Science Magazine.

White and co-author Mary Beth Hall added that the reduction in greenhouse gas emissions around the globe would only be around 2.6 percent.

The average American currently reportedly eats around 214 pounds of meat – including beef, pork, and chicken – each year. That number is far above the global average of 75 pounds of meat eaten annually. The researchers say that while a diet change may be helpful, it’s not a perfect solution to the problems of climate change.