Meanwhile, the gap between those who don't have enough to eat and those who have too much will persist, the report says.
The researchers analysed changes in global eating habits since 1965 and looked at factors such as demographic changes, food waste and declining physical activity to predict how food demand might change going forward.
They found that on a "business as usual" model - a continuation of current trends - 45 per cent of the world's population will likely be overweight by 2050, of whom 16 per cent would be obese.
By 2100, the proportion of the population that is overweight could surge to 56 per cent.
That compares to 29 per cent of the population who were overweight in 2010, including 9 per cent who were obese.
In addition, with both food waste and meat consumption rising, "the environmental impact of our agricultural system will spiral out of control", said Benjamin Bodirsky, lead author of the study published in Nature Scientific Reports.
"Whether greenhouse gases, nitrogen pollution or deforestation: we are pushing the limits of our planet - and exceeding them."
Despite veganism becoming increasingly popular in recent years, the authors said that eating habits globally are continuing to move away from plant- and starch-based diets to more "affluent diets" that are high in sugar, fat, meat, and processed foods. On current trends, the demand for animal products like meat and milk will approximately double by 2050.
But despite the expected growth in waistbands, inequality and high levels of food waste mean that half a billion people will still be undernourished by 2050, according to the analysis.
The researchers explained that producing animal-based foods requires more land than producing plant-based foods and releases more greenhouse gas emissions. The consequence is that if meat production increases, there is less plant-based food for other people to eat. People in wealthy countries and communities also throw away too much food.
"There is enough food in the world - the problem is that the poorest people on our planet have simply not the income to purchase it," said co-author Prajal Pradhan. "And in rich countries, people don't feel the economic and environmental consequences of wasting food."
Rising weights will also burden health systems, leading to higher levels of diabetes, heart disease and cancer.
Already, the World Health Organisation describes obesity as having reached "epidemic proportions", with at least 2.8 million people dying each year as a result of being overweight or obese.
The researchers called for urgent political measures to promote healthy eating, including limits on the marketing of unhealthy foods and a stronger focus on nutrition education in schools.
