Do you realize that by chucking that half finished burger into the trash you're contributing to global warming? Americans waste around 1,400 calories worth of food per person each day. That's 40 percent of the total food supply.

Don't believe me, ask the people from the National Institute of Diabetes and Digestive and Kidney Diseases in Maryland. According to them, food waste has increased 50 percent since 1974. What's that got to do with the environment? Well, food waste accounts for 25 percent of fresh water use in the US and 300 million barrels of oil. That's around 4 percent of the country's total oil consumption.

“Food waste contributes to excess consumption of freshwater and fossil fuels which, along with methane and CO2 emissions from decomposing food, impacts global climate change,” the Maryland scientists write in the online journal Public Library of Science ONE.

And that's not all. The increase in food waste may well demonstrate an excessive quantity of cheap food that would help explain the rise in obesity - from 1.5 percent of the population in 1980 to 34.3 percent now - more than double. Not forgetting the 32.7 percent more who, according to the US Department of Health and Human Services, are overweight. (And there's no room for 'merely' in that sentence.)

“The calculated progressive increase of food waste suggests that the US obesity epidemic has been the result of a ‘push effect’ of increased food availability and marketing with Americans being unable to match their food intake with the increased supply of cheap, readily available food,” the authors wrote. “Thus, addressing the oversupply of food energy in the US may help curb the obesity epidemic as well as decrease food waste, which has profound environmental consequences.”

So: if America's food waste problem were tackled, maybe it would help ease global problems of food shortages is what they're suggesting. If you've managed to read this far, here's a bit more: to work out the quantiy of food waste, they developed a mathematical model to calculate American food consumption based on body weight and metabolism. Then they compared their results with information about the US food supply. From that, they claim that previous calculations may have underestimated American food wastage by up to....Guess: a) 5 percent b) 15 percent c) 25 percent.

Yes, that sinking feeling told you c) was the right answer.