Most Americans think they’re healthier than they actually are.

Considering that well more than 60 percent of the U.S. population is struggling with weight problems, that is quite surprising. Yet 80 percent of participants in a recent survey identified themselves as “extremely healthy” or “very healthy.”

But only 20 percent claimed to have what is considered an all-around healthy diet, according to the NPD group, a leading market research company that conducted the study.

Despite of the overly positive self-assessment, about half of the almost 2,000 adults who were interviewed agreed that their existing diet could use some help. Roughly half of those said that changing their eating habits would require some exclusion of certain foods (presumably of lesser nutritional quality) as well as inclusion of others (presumably of higher nutritional quality). Twenty-six percent saw the need to add more healthy foods, and only 19 percent thought they needed to cut back on what they usually ate. There were slightly fewer respondents claiming to be on a weight loss diet than in previous years when similar research was done.

Other studies have found that it is not rare for people who are overweight or obese to misjudge their size, sometimes considerably.

Researchers from the University of Illinois at Urbana-Champaign found in a study on weight problems among young Hispanics that only a minority of overweight or obese participants judged their body size accurately.

Nearly 60 percent of those whose BMI identified them as overweight described themselves as normal weight, while 75 percent of those who were obese thought they were merely overweight. One in three women does not realize when she gains five pounds and 15 percent aren’t aware of weight increases of more then 10 pounds, according to a survey by the University of Texas in Galveston.

Even for Americans who are interested in eating better and keeping their waistline from expanding, maintaining a healthier lifestyle remains an uphill battle. Food prices, especially for fresh produce, are high and keep rising. Contradictory messages like a recent study that questioned the benefits of buying organic add more uncertainty. Many consumers either give up altogether or make inconsistent dietary decisions.

“There’s complete confusion,” said Maria Mogelonsky, a food analyst for a global marketing firm in an interview with the New York Times on the subject. “Most people have a randomly arranged set of diet principles. They buy organics sometimes. They buy based on price sometimes. Very few people are completely committed to one cause,” she said.

So what advice is there to give?

• The first thing I tell my clients is not to make their dietary improvements too complicated. If your new regimen doesn’t fit your lifestyle, it won’t stick, no matter how hard you try.

• Learn a few basic facts about nutrition (your body needs over 40 different nutrients every day), and how you can achieve and maintain balance in your diet.

• Don’t start controlling your food intake by counting calories. Rather, watch your portion sizes. Your stomach’s size is roughly equivalent to the size of your fist. Your servings should not exceed that.

• Gradually increase your consumption of healthy foods like fruits and vegetables. At the same time, decrease your intake of processed and packaged foods.

• Buy fresh produce as much and as often as it fits your budget. To save costs, choose locally grown, seasonal items whenever possible. Farmers markets can offer better quality at lower prices than supermarkets.

• Prepare most of your meals from scratch. Eating out or grabbing some take-out on the way home should be the exception, not the rule.

• Make water your primary beverage. Avoid sodas and keep caffeine and alcohol to a minimum.

• Get enough exercise to burn off calories your body doesn’t need.

If all or some of this is too challenging for you right now, take the steps you can manage and work toward the rest as you go.

Timi Gustafson R.D. is a clinical dietitian and author of the book “The Healthy Diner – How to Eat Right and Still Have Fun”®, which is available on her blog, “Food and Health with Timi Gustafson R.D.” and at amazon.com. You can follow Timi on Twitter and on Facebook.