Every year, Americans are inundated with new fad diets and weight-loss programs that can supposedly help shed 20 pounds or more in just a week. These programs are pushed by fly-by-night gurus and hucksters who understand that people are often motivated by instant results that rarely endure, not by the work it takes to achieve lasting success.

As any credible health professional will tell you, the only way to realize and sustain healthy weight loss over the long-term is with discipline, a balanced diet, and a consistent regiment of exercise.

So what does this have to do with energy and climate? Because the same forces may be underway in the U.S. energy sector.

The graph below represents America’s “carbon weight” — otherwise known as carbon emissions from the energy sector. And it shows an improvement. Q1 Carbon emissions from the energy sector are at the lowest level they’ve ever been for the last 20 years. Seen from a narrow weight loss perspective, that’s a really good thing.

So bravo, America. You’ve made great progress since you last went to the doctor’s office — an 8 percent decrease in carbon poundage! But to holistically assess the nature of your progress, we need to take a little survey.

What have you been consuming since we last saw you?

Natural gas?

Hmm. You do realize that’s considered the “crack cocaine” of the utility industry, right? And while natural gas is certainly “cleaner” for your system when burned compared to coal, it’s still a fossil fuel that contributes excess carbon poundage. Scientists and public health officials are also still trying to determine all the other consequences — things like water contamination and methane leakages — that may harm your health in other ways.

At least you’re consuming less coal. In fact, you’ve reduced your consumption of coal by almost 20 percent compared to the first quarter of 2011 — a stunning decrease. Your carbon emissions from coal dropped 18 percent through March. You’ve also dramatically increased your share of healthy efficiency and renewable energy compared to your previous energy diet — but it’s still not nearly enough.

And how have you been feeling?

I see your temperature continues to rise. You had the hottest 12 month period on record, the hottest half year on record in 2012, the hottest July ever, and you’ve already broken or set more than 27,000 high temperature records so far this year — more than all of 2011.

You also feel like you’re getting addicted to cheap gas? Yes, that’s worrisome not only for your carbon weight, but for your wallet. After all, many experts believe estimates of the amount of gas available for consumption are wildly inflated. That could drive up prices sooner than you think.

And while you’ve made excellent choices in reducing your coal use, you’re still relying on gas, you’re still pushing coal to the rest of your friends in the international community, and it looks like you’re considering a new president who wants to force you back on a dangerous high-coal diet.

To put it bluntly, America, you aren’t exactly living the healthy lifestyle that your carbon weight loss would suggest.

Many are hailing the latest dip in carbon emissions as an energy miracle when, in fact, it’s being largely driven by short-term gains in natural gas combined with a warmer-than-average winter. Most believe that natural gas plays a role in America’s energy diet in varying degrees; however, a growing number of experts — including those at the International Energy Agency — say that natural gas would be an emissions disaster if built out too aggressively over the medium-term.

The Associated Press had a great piece on the trend yesterday:

The question is whether the shift is just one bright spot in a big, gloomy picture, or a potentially larger trend.

Coal and energy use are still growing rapidly in other countries, particularly China, and CO2 levels globally are rising, not falling. Moreover, changes in the marketplace — a boom in the economy, a fall in coal prices, a rise in natural gas — could stall or even reverse the shift. For example, U.S. emissions fell in 2008 and 2009, then rose in 2010 before falling again last year.

Also, while natural gas burns cleaner than coal, it still emits some CO2. And drilling has its own environmental consequences, which are not yet fully understood.

“Natural gas is not a long-term solution to the CO2 problem,” [Roger] Pielke warned.

Along with the many environmental and public health uncertainties about natural gas, the AP piece also looks at price volatility, a problem that has been largely lost in the energy conversation due to suppressed prices in recent years:

Last year the Environmental Protection Agency issued its first rules to limit CO2 emissions from power plants, but the standards don’t take effect until 2014 and 2015. Experts had predicted that the rules might reduce emissions over the long term, but they didn’t expect so many utilities to shift to gas so early. And they think price was the reason.

“A lot of our units are running much more gas than they ever have in the past,” said Melissa McHenry, a spokeswoman for Ohio-based American Electric Power Co. “It really is a reflection of what’s happened with shale gas.”

“In the near term, all that you’re going to build is a natural gas plant,” she said. Still, she warned: “Natural gas has been very volatile historically. Whether shale gas has really changed that — the jury is still out. I don’t think we know yet.”

Although natural gas has forced a major reduction in coal consumption — an excellent short-term development — we have a coal industry prepared to push its product to anyone in the international community who wants it. And beceause our carbon diet is inextricably tied to the diets of other countries, that decision will also harm our health:

Jason Hayes, a spokesman for the American Coal Council, based in Washington, predicted cheap gas won’t last.

“Coal is going to be here for a long time. Our export markets are growing. Demand is going up around the world. Even if we decide not to use it, everybody else wants it,” he said.

In other words, we don’t really know if the recent changes are a “fad” or the sign of a healthy change in the energy diet of America. Will we succumb to the exciting, immediate results of natural gas, only to find that we can’t keep the weight off? Or will we embrace the right choices to make the country more efficient and clean — putting us on a path to dropping that carbon weight for good?