In a nutshell, a study published in the Proceedings of the National Academy of Sciences suggested that eating less meat and more vegetables could save both human lives and the whole planet as well. 

This means that mankind's dietary habits are impacting climate change, while unhealthy diets are causing premature mortality rates. Furthermore, the study states: 

We project that health and climate change benefits will both be greater the lower the fraction of animal-sourced foods in our diets. Three quarters of all benefits occur in developing countries although the per capita impacts of dietary change would be greatest in developed countries. 

This implies that by eating more vegetables and less animal-based diets, health and climate change beneifts will be experienced by the whole planet. Most of these will also be experienced in developing (third world) countries, though the economic implications of dietary changes will have a bigger impact in developed ones. 

Meat and climate change

According to the study, food-related greenhouse gas emissions may be one of the major reasons why negative climate change is occurring. With that said, it argues that emissions done by the industry, which is responsible for a third of the overall greenhouse gases released by human beings, could significantly fall by 29 to 70 percent by the end of 2050 if mankind were to adhere to a strict dietary guidelines. 

Mortality and money

Additionally, the report states that global mortality will drop by as much as 10% if this is adhered to, potentially preventing at least eight million deaths a year. These deaths are caused mainly by diseases stemming from poor diets. Money will also be saved - between a one and 31 trillion. 

Is this possible?

The report says that eight million lives could be saved if the planet were to go vegan. Though the study optimistic scenarios, the possibility of the world eating a meat-free diet is close to impossible, given that on average, a meat-eating person consumes 41 kilograms of meat a year.