World Will Need 80 Percent More Calories by 2100 to Feed Exploding Population, And We Might Not Meet Demand

The number of calories needed to feed the world could almost double by the century's close, as populations and body weight continue to rise.

A study published in Plos One calculated how much food would be needed to feed the global population of 2100 if current trends continue. The answer is almost 80 percent more than what was needed in 2010.

Approximately 60 percent of that figure comes from the fact that there will be more mouths to feed. According to Pew Research, the planet's population is expected to increase to around 10.9 billion people by 2100. That is 3 billion more than the 7.8 billion people alive in 2019.

Another 18 percent growth in demand is the result of increases in height and weight. Body Mass Index (or BMI) is increasing in most countries, the researchers say—pointing to stats that show the global average has increased 2.5 kilograms per meters squared (in men) and 2.3 kg/m2 (in women) between 1975 and 2014. Thus the calorie demand from each individual person is projected to increase.

The researchers estimate the average daily requirement will increase from 2285 calories per person in 2010 to 2425 calories per person in 2050 and 2538 calories per person in 2100. That is an extra 253 calories, which is the equivalent of two large bananas or a portion of French fries, co-author Lutz Depenbusch told BBC News.

On a global scale, this equates to an increase equivalent to India and Nigeria's combined requirement in 2010. These two nations had a combined population of nearly 1.4 billion in 2010 according to World Bank data.

Tractor in German farm
A farmer drives his tractor in a field near the small Bavarian village of Biburg, southern Germany. The world's calorie needs are expected to increase 80 percent by the century's end. CHRISTOF STACHE/AFP/Getty

Depenbusch, then a doctoral student at the University of Göttingen, and Stephan Klasen, a professor in the Faculty of Business and Economics, came to these conclusions using changes to the weight of people in Mexico and the height of people in the Netherlands between 1975 and 2014—which provide a "very pronounced" but "realistic scenario," Depenbusch said in a statement.

Are we prepared to meet these new demands? Depenbusch and Klasen did not study this question in detail but they describe a more likely scenario as one "accompanied by starvation for many, often affecting the most vulnerable groups the most."

The rich might be able to maintain their diets, eating similar foods to what they do today. It is the poor that are set to suffer from the higher prices brought on by higher demand, the researchers say.

"This would lead to increased consumption of cheap food, often rich in calories but poor in nutrients," Depenbusch said in a statement. "As a result, body weight among the poor would continue to rise alongside malnutrition and poorer health outcomes."

Depenbusch and Klasen call for policies that increase access to food in poorer areas: "Such policies should shift consumption away from energy dense foods that promote overweight and obesity, to avoid the direct burden associated with these conditions and reduce the increases in required calories."

Calorie Demand
Percentage change in the annual amount of calories required by the population between 2010 and 2100, assuming an increase in body weight and given population growth. While many European countries will see a decline in energy requirements, other areas like countries in central Africa will see high increases. Lutz Depenbusch