A vegetarian diet has a clear positive effect to people but not to the environment, as scientists have found this could contribute to climate change by delivering more carbon emissions. A new study shows the consumption of more vegetables, fruits, dairy and even seafood could be more harmful to the environment due to relatively high resource uses and greenhouse gas emissions per calorie.

Researchers from Carnegie Mellon University in the US claim eating more lettuce is more than three times worse in greenhouse gas emissions than consumption of bacon. Diets with more eggplant, celery and cucumbers were found particularly bad when compared to pork or chicken.

The findings come from the analysis of the food consumption patterns in the US The researchers looked into energy and water use and greenhouse gas emissions from food production, transportation, sales and service, and household storage and use.

"Lots of common vegetables require more resources per calorie than you would think,” said Paul Fischbeck, professor of social and decisions sciences and engineering and public policy. The researchers said that vegetarian diet still has a positive effect on the environment, which is helping to reduce energy and water use and the harmful emissions from the food supply chain by about 9 per cent.

However, the study published in the journal Environment Systems and Decisions shows eating “more” fruits, vegetables, dairy and seafood has increased the environmental impacts of the food supply chain. Energy use increased by 38 per cent, water use by 10 percent and harmful greenhouse gas emissions increased by 6 per sccent.

"There's a complex relationship between diet and the environment," said Michelle Tom, a Ph.D. student in civil and environmental engineering. "What is good for us health-wise isn't always what's best for the environment.”

The researchers suggest that public officials should consider the effects of food production on the environment for future development of dietary guidelines.

Contact the writer at feedback@ibtimes.com.au or tell us what you think below