It's hard enough to save for retirement without having your employer working against you. But if your employer doesn't give you good investment choices in your 401(k), you'll find it even more difficult to reach your goals.

A recent story in The Wall Street Journal pointed out that many employers are scaling back their use of low-cost index funds in their 401(k) plans, replacing them with more costly, actively managed mutual fund choices. Citing a study in which researchers looked at the options offered within 401(k) plans, these actively managed funds actually underperformed index funds despite their higher costs.

You vs. them
Unfortunately, this isn't the only thing you have to worry about in your retirement plan at work. Legally, as the party responsible for running your retirement plan, your employer has a fiduciary duty to its employees to look out for their best interests. That's how employees of companies like Boeing (NYSE:BA) and Deere & Co. (NYSE:DE) have challenged retirement plans with high fees, and how Xerox (NYSE:XRX) and Avaya (NYSE:AV) employees have tried to get compensation when their employer stock lost value.

But employers still often look out for their own interest, even if it's detrimental to employees. Running a retirement plan can be expensive for employers. Traditionally, when more employers used defined benefit pension plans, they often covered the costs of administering their pension plans and investing their assets. With the shift to defined contribution plans, however, it's been easy to transfer those costs to employees.

Funds and fees
One way employers can shift plan costs to employees is in their choice of funds. Some actively managed funds offer revenue-sharing opportunities, by which part of the money collected in fees from plan participants goes back to the employer or the firm the employer hires to administer the plan. By selecting these funds, employers and plan administrators reduce their costs and increase their profits at the expense of employees.

Of course, if those funds performed well, the higher costs wouldn't be such a bad thing. But typically, the funds that can afford to pay back money in revenue sharing tend to have pretty high expenses compared to their peers. And actively managed funds with high expenses have a big handicap working against their performance -- a handicap that many can't overcome. According to Fool fund expert and Champion Funds advisor Shannon Zimmerman, as counterintuitive as it may seem, when it comes to funds, you get what you don't pay for.

What you can do
If you don't see investment choices you like in your employer's retirement plan, talk to your payroll or HR department about it. One reason why employers offer 401(k) plans is that they think they're valuable for their workers. If your employer hears enough comments to the contrary, then you might see some changes.

If that doesn't work, then you may have to make do with what's available. If all of your choices are really bad, then it may actually make sense to avoid your retirement plan entirely and save in an outside IRA. Often, though, you'll find one or two decent choices among the alternatives.

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To learn more about investing for retirement, check out the Fool's Rule Your Retirement newsletter. Foolish expert Robert Brokamp looks at a wide range of retirement topics every month. A free 30-day pass gives you access to three years of materials. Let Rule Your Retirement help you start to plan for your retirement today.

Fool contributor Dan Caplinger now gets to make his own 401(k) choices. He doesn't own shares of the companies mentioned in this article. The Fool's disclosure policy is never a bad choice.