Obese people need at least 18 percent excess food energy as compared to their thinner counterparts, researchers from London School of Hygiene and Tropical Medicine have revealed.
For the study, Phil Edwards and colleague Phil Roberts estimated the hypothetical difference in food consumption of 1 billion obese and 1 billion lean people.
The pair calculated the dietary intake of lean people with a body-mass-index (BMI) of 24.5 and examined it with the diet of overweight people with a BMI of 29.
The findings revealed that lean individuals consumed an average of 2500 calories per day, while obese individuals 2960 calories.
The amount of calories consumed by lean people was 18 pct less than the obese.
When further divided into 'resting' and 'active' components, the results revealed that obese people consumed 1680 calories per person per day just to tick over, compared with 1550 calories for leaner people.
"It's just due to being fatter," New Scientist quoted Edwards, as saying.
"Larger people need more energy just to move blood round the body, maintain larger bodies and keep the heart pumping," he added.
Meanwhile, a report released on May 14 by the Stockholm International Water Institute expressed concerns over how by fresh water was getting contaminated with people throwing away food in it.
"That's like leaving the tap running and pouring 40 trillion litres of water into the garbage can - enough water to meet the household needs of 500 million people for a year," said the report, Saving Water: From Field to Fork, jointly launched with the UN's Food and Agriculture Organization and the International Water Management Institute.
The report appears in journal The Lancet.