With food and fuel costs soaring and the financial costs of global warming becoming reality, a new cure-all prescription has emerged: The average American should eat less.

And with a new University of Illinois report forecasting even higher food prices next year, the suggestion could become an inevitable way of life for people on tight budgets. It would of course have the added benefit of trimming waistlines and improving health, which would provide additional savings in reduced health care costs.

And cutting back would reduce greenhouse gas emissions, scientists point out, helping reduce the billion-dollar price tags put on damage and woe predicted to come with a warming world.

Fat and unhappy

Roughly 19 percent of U.S. energy consumption goes toward producing and supplying food, David Pimentel and his colleagues at Cornell University write in the current issue of the journal Human Ecology. Considering that the average American consumes an estimated 3,747 calories a day, — at least 1,200 more than health experts advise — the researchers suggest everyone cut back.

Animal products and junk food, in particular, use more energy and other resources for their production than staples such as potatoes, rice, fruits and vegetables.

Producing all the stuff that goes into a single hamburger, for example, requires some 1,300 gallons of water, according to the U.S. Geological Survey. A study in 2006 by University of Chicago researchers Gidon Eshel and Pamela Martin found that a vegetarian diet is the most energy-efficient, followed by one that includes poultry. Diets with red meat or fish are the least efficient.

"By just reducing junk food intake and converting to diets lower in meat, the average American could have a massive impact on fuel consumption as well as improving his or her health," Pimentel and his team write in a statement released today.

The idea is not brand new. As LiveScience's Bad Science columnist Benjamin Radford put it earlier this year: "If you really want to help save the Earth, you can start by dropping a few pounds."

You may have to cut back

Meanwhile, prices at the grocery store could force changes in consumption.

Soaring energy prices will yield sharp increases for corn and soybean production next year, according a separate study announced today. Fertilizer prices are expected to surge 82 percent for corn and 117 percent for soybeans, said Gary Schnitkey, an agricultural economist at University of Illinois.

"Roughly 80 percent of the cost of producing nitrogen fertilizer is natural gas, so as natural gas costs have gone up so have the costs of those inputs," he said.

Rising fuel prices also mean it costs more to harvest and transport food.

While farmers will likely absorb some of the added costs, Schnitkey says consumers also should expect to pay more for products ranging from cereals and syrups to grain-fed beef.

"There's not going to be a reduction back to lower food costs as long as we have these higher production costs," Schnitkey said. "Energy prices are driving a lot of what's going on and ultimately that hits the consumer."

Additional savings

If people ate less, and therefore fossil fuel consumption declined, other savings could ensue.

For instance, a third study coincidentally also out today finds that global warming, fueled by greenhouse gases emitted by the burning of fossil fuels, is costing money in the United States and that situation will grow worse. The scientists argue that costs will be in the billions for each of the eight states included in the study: Colorado, Georgia, Kansas, Illinois, Michigan, Nevada, New Jersey and Ohio. California and other well-studied states were not included.

The losses will be due in part to water resource issues, coastal flooding, health effects and reduced tourism.

"We don't have a crystal ball and can't predict specific bottom lines, but the trend is very clear for these eight states and the nation as a whole: Climate change will cost billions in the long run and the bottom line will be red," said Matthias Ruth, who coordinated the research and directs the Center for Integrative Environmental Research at the University of Maryland. "Inaction or delayed action will make the ink run redder."

The study was funded by the Environmental Defense Fund.

You're in control

The Cornell study led by Pimentel argues that the consumer is in the strongest position to contribute to a reduction in energy use.

"As individuals embrace a 'greener' lifestyle, an awareness of the influence their food choices have on energy resources might be added encouragement for them to buy good, local produce and avoid highly processed, heavily packaged and nutritionally inferior food," the scientists write. "As well as leading to a cleaner environment, this would also lead to better health."

Scientists say cutting calories is one of the sure-fire ways to extend the human life span. It might also improve your sex life: Scientists found last year that obesity is linked to erectile dysfunction.