A central target in financial reform has been derivatives. They have been blamed for the economic meltdown, and many people are calling for their strict regulation. So what are these financial rascals, and how do they affect the economy?

Derivatives protect people from a change in prices of an underlying asset. They began, generally speaking, as a hedge against changes in commodities prices. So, if you are a corn farmer and want to be able to plan on how much you will receive for your crop, you can agree on the price with a miller. The farmer is in a sense betting that the price will be higher or at least the same as the rest of the market at harvest time, and the miller is betting that the price will be lower or at least the same – and the miller is ensured of a supply of corn. The result is stability for both parties. The agreement is derived from the underlying asset of corn. That is the essence of a derivative.

Derivatives also hedge against price changes in other financial instruments and can become far more complicated or “exotic.” An institution can buy a credit default swap (CDS), for example. Institution No. 1 would pay institution No. 2 to ensure that the value of an asset does not fall under a certain level. If the value does drop, then No. 2 would pay No. 1. When the value of real estate plummeted in 2007 and 2008, many No. 1 institutions were banging on No. 2 institutions’ doors to get paid. This was one of the factors leading to the economic collapse, when the overall value of the CDS market dropped from $62.2 trillion at the end of 2007 to $38.6 trillion at the end of 2008, according to the International Swaps and Derivatives Association.

Another factor was collateralized debt obligations (CDOs). These are packages of debts such as bonds or mortgage-backed securities. The idea is to reduce risk by spreading it around. But some in finance, such as Warren Buffett, said that they instead spread risky investments to more institutions. So when the underlying, or derived, asset plummeted, the rug was pulled out from under everyone.

Although some, like Buffett, had sounded the alarm on derivatives, many people were surprised by the enormous impact the instruments had on the financial sector in the collapse of September 2008. Regulators were also surprised, because derivatives are often unregulated because they are essentially an agreement exchanged between parties but amount to a $400 trillion market traded over the counter (OTC).

Financial reformers want to shed more light on the market, but on April 21, a Senate committee went even further than that and approved tough standards that would force banks to get rid of their swaps trading operations. That rule might not make it to the final financial reform package, but it is certain that the eventual law will clamp down on derivatives in some way.

When people are working, they might not realize how big an impact taxes will have on their retirement lifestyle. Taxes end up being among the most significant expenses seniors face.

Once you start tallying up the federal, state and local taxes, you can see you have to be aware of how to mitigate the impact. One way is to choose a place to retire that does not have onerous state and local taxes.

For example, nine states have no state income tax, according to the Federation of Tax Administrators. They are  Alaska, Texas, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Washington and Wyoming. (In New Hampshire and Tennessee, income tax is limited to dividends and interest income.)

According to the Tax Foundation, the states with the highest tax impact are Maine, New York, Ohio, Minnesota and Hawaii. The ones with the lowest are Alaska, New Hampshire, Delaware, Tennessee and Alabama. The foundation also says that Americans will pay more in taxes in 2010 than they will spend on food, clothing and shelter combined. Another factor to consider, if you have a large inheritance to leave, is whether the state has an estate tax.

If you move, the good news is the tax impact of selling your home is less these days. That’s because Congress changed the rules in 1997. According to the book The New Retirement, by Jan Cullinane and Cathy Fitzgerald, “Some or all of the gain on the sale is not taxable as long as the taxpayers owned the house as their principal residence for at least two years during the five-year period ending with the date of the sale. The amount of gain that is not taxable is limited to $250,000 for a single taxpayer (or a single taxpayer limited separately) and $500,000 for a married couple filing a joint return. Significantly, unlike under the old law, this gain is eliminated from taxable income and is not deferred to reduce the tax basis of any replacement residence.”

Cullinane and Fitzgerald also wrote that the sellers do not have to buy a replacement principal residence, so it especially benefits those wanting to downsize.

The health-care reform legislation has many consequences, but one that has not received much attention is a new calorie-labeling requirement for restaurants and even vending machines.

The law would require restaurants with 20 or more establishments to post the calorie counts on menu boards and next to each item in vending machines. The information will be similar to the information on food products bought at the supermarket. Restaurants were previously exempted from that law.

Some argue this is a key part of controlling obesity, because people are eating out more these days and are uncertain about how many calories they are consuming. In fact, the Center for Science in the Public Interest (CSPI) said children eat twice as many calories at restaurants than at home.

People might be shocked by some of the numbers. Consumers might not be surprised to find out the Guacamole Bacon Six Dollar Burger at Carl Jr.’s is 1,117 calories (more than half the calories a person should have in a day). But they might be shocked to learn that the double beef taco salad with dressing that they might have had at the Steak ‘n Shake has 1,051 calories.

Research shows people are not very good at judging calories on their own. A Cornell University study found that people make nearly 20 times more daily decisions about food than they are aware of — an average of around 250 each day.

Portion control is another practice the calorie information can encourage. At McDonald’s, for example, a small order of french fries is 210 calories. But supersize that and it’s 610 calories. Consumers might also be misled by the fixings. At Steak ‘n Shake, a junior order of fries is a mere 166 calories. But go for the chili cheese fries and you have consumed a whopping 1,279 calories.

In other words, the calorie labeling is sure to add a whole new dimension to the question, “Do you want fries with that?”