Okay, time for a reality check.

If you need an extra nudge to get with a healthy eating and exercise program for 2003, maybe this will help: Not only did the government report last week that the obesity epidemic is getting worse throughout the population, but the latest research shows that the ill effects of being overweight and obese in middle age now rival those of smoking.

That's right: America is eating itself into health problems just as it smoked itself into them in earlier decades.

The most recent results from the well-known Framingham Heart Study find that just being overweight at age 40 trims three years from the life expectancy of men and women compared with their healthy-weight counterparts. (And please note that none of these folks were smokers.)

Not surprisingly, obesity extracts an even tougher toll. The study found that 40-year-old women who didn't smoke but had a BMI, or body mass index, of 30 or more, died seven years earlier than healthy weight women. Obese men shaved five years off their lives. (Add smoking to the mix and the numbers get even worse: 13 years for obese female smokers; 14 for obese male smokers.)

So maybe you're newly motivated to eat well in 2003. If so, here's a quick look back on what was learned in 2002 and remains worth keeping in mind:

Flexibility in nutrients. In issuing new guidelines last year, the National Academy of Sciences (NAS) left a lot of wiggle room for various nutritional approaches. For carbohydrates, it set a recommended dietary allowance of 130 grams a day for both adults and children, a level that is based on the amount of glucose needed by the brain. (A slice of whole-wheat bread contains 13 grams; one medium apple has 21 grams and a cup of green beans has 10 grams.) The NAS noted that most Americans far exceed the recommended amount of carbs. For fat, the NAS set 20 percent to 35 percent of total calories as an "acceptable" range. The report sets 56 grams of protein as the recommended daily intake for men and 46 grams for women. (These numbers are based on a 154-pound man and a 127-pound woman. If your weight is significantly different, you may want to do the math: 0.37 grams of protein for every pound of body weight for adults 19 years and older.)

There are no "bad" foods. In recent years, many foods, from eggs to coffee, have been demonized. Carbohydrates are the latest on the hit list. But just as there are healthy and less healthy fats and protein, there is a wide range of carbohydrates: the highly processed sugar and flour found in Hostess Twinkies, for instance, vs. the natural sugars in a pear. In proteins, there is a Big Mac, high in saturated fat, and an egg white, with zero fat. And as the U.S. Dietary Guidelines note, fat is not a four-letter word. In fact, last year the research was strong enough on healthy types of fat that the NAS set an adequate daily intake for omega-3 and omega-6 fatty acids to be sure that Americans get some of these fats every day. They're found in such foods as nuts, avocados, fish, flaxseed and safflower oil. The emerging consensus seems to be that it's wise to make more nutritious choices within food categories rather than banning or embracing any one.

Yes, you can lose weight, at least briefly, on the Atkins diet. The U.S. Department of Agriculture noted this very thing in 2001. In 2002, a couple of studies -- one paid for by the American Heart Association (AHA), the other by the Atkins Foundation -- found that people on the very-low-carbohydrate approach advocated by physician Robert Atkins lost significantly more weight than traditional, low-fat, higher-carbohydrate weight loss diets. But in the AHA-funded study, when participants were left on their own during the second phase of the study, the Atkins group could not fully sustain the very-low-carb approach. They added back fruit and vegetables but kept processed carbs -- bread and pasta, for example -- lower than the low-fat group did. The low-fat group stuck with their regimen throughout the study, but did not lose as much weight.

Preliminary results from the other study, which was presented at the AHA annual meeting in November, showed that both groups of dieters reduced levels of low-density cholesterol (LDL) by 73 percent. (Elevated cholesterol has been a concern about the Atkins approach.) Authors of both studies cautioned that more research is needed about long-term safety, compliance and weight-loss maintenance for the Atkins diet.

Exercise! Yes, you've heard it a thousand times -- okay, maybe a million -- but findings on the benefits of various types of physical activity only grow stronger. Sure, trimming calories will help move the scale in the right direction. But you're making things much harder on yourself if you don't boost physical activity, too. In fact, the latest NAS recommendations set 60 minutes daily as the goal for most Americans to achieve a healthy body weight. And no, you don't have to log that time at the gym. Brisk walking -- about 4 miles per hour -- is sufficient to meet the recommendation.Check out your physical activity IQ at www.nhlbi.nih.gov/health/public/heart/obesity/phy_act.htm.

Confused about what to eat? Even some scientists, including Harvard School of Public Health's Walter Willett, are debating what's best. Where they agree: on the dangers of saturated and trans fatty acids and the benefits of beans, fruit, vegetables, nuts, vegetable oils and whole grains, low-fat dairy products and (in moderation) alcohol. They also underscore that you have to take in at least slightly fewer calories than you expend if you want to lose weight. Check out the latest NAS nutritional recommendations at www.nap.edu/books/0309085373/html/. See how your food preferences rate with the dietary guidelines at http://147.208.9.133/ and with Willett's revised food guide at www.hsph.harvard.edu/nutritionsource/.

-- Sally Squires

How do you plan to eat healthy this year? Share your tips -- or ask any question about nutrition -- when Sally Squires hosts the Lean Plate Club, our online chat about healthy eating and exercise, from 1 to 2 p.m. today at www.washingtonpost.com. To subscribe to the free electronic Lean Plate Club newsletter, log on to www.washingtonpst.com/wp-srv/email/front.htm.