In the latest Global Nutrition Report, researchers examined just how bad a poor diet is for the body, and turns out it's worse than puffing on cigs. The report was independently produced.
"Diets are one of the top risk factors of morbidity and mortality in the world - more than air pollution, more than smoking," says Jessica Fanzo, a lead author and a professor at Johns Hopkins University.
"What we're eating is killing us. So something needs to get us back on track with our food system."
The authors credit a lack of knowledge and affordability as key reasons for poor diets.
After analysing 194 countries, researchers estimated that malnutrition could cost the world US$3.5 trillion a year while weight-related issues could cost $500 billion annually.
Co-chair of the Global Panel on Agriculture and Food Systems for Nutrition, Sir John Beddington suggest that reducing food waste could improve nutrition.
"Each year more than half of all the fruits and vegetables produced globally are lost or wasted," said Beddington, speaking to the Thomson Reuters Foundation.
Ms Fanzo also adds that diet is important in improving immunity and keeping the brain healthy.
"You have to care about what people are eating if you want to build the intellect of your country," she added.