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Conflicting Studies Make It Hard to Choose How to Lose

Obesity: Counting calories is the road to weight loss. Or is keeping track of fat the way? Or is it keeping a food diary? Even diet researchers admit theirs is not an exact science.

February 21, 1996|KATHLEEN DOHENY | SPECIAL TO THE TIMES

Let's say you're overweight--a recent Louis Harris poll finds that 74% of adult Americans are--and you're trying to figure out the best way to drop those pounds.

You know you can do it, if only you could find the perfect weight-loss plan. No small feat. One week, a much-ballyhooed study claims low-fat is the way to go, only to be overshadowed by another study claiming exercise--or old-fashioned calorie-counting--is the key.

Here's a roundup of some of the findings from weight loss studies published recently in medical journals. (Easily frustrated types, grab the giant bag of chips now.)

To Count or Not to Count

Traditionally, dieters have counted calories. Then came the concept of counting fat grams, touted as an easy way to reduce total calories.

Or is it?

James O. Hill, associate professor of pediatrics and medicine at the University of Colorado Health Sciences Center, Denver, compared the two approaches in a study published in the International Journal of Obesity in 1993.

The dieters who restricted calories lost more weight in 16 to 20 weeks than those who restricted fat grams. (Calorie-counting men lost 26 pounds; the women, 18. Fat-gram counting men lost 17.5 pounds; the women, 8.5.)

But last year, the same journal published another study that suggests eating a low-fat, high-fiber diet is the way to lose. Those who did so during the 11-week study lost an average of 3 pounds, even though they ate all the carbohydrate-rich and fiber-rich foods they wanted and actually increased their total daily calories.

To Track or Not to Track

Writing down what you eat as you eat it (no fair reconstructing the diary at the end of the week) is an effective weight-loss tool, especially in a long-term program, says Victor J. Stevens, senior investigator at the Kaiser Permanente Center for Health Research, Portland, Ore., who has published his findings in the Journal of the American Dietetic Assn. and other publications.

Food records or diaries work, he says, even though people usually underreport their actual intake. "What we find is people who do this begin to change what they eat. It's even better if you post the record."

The secret, say others, is to eat only food provided to you as part of the weight-loss program. Researchers from the University of Minnesota found that 202 dieters lost more weight when food was provided for them, according to a report published in 1993 in the Journal of Consulting and Clinical Psychology.

But before you plot to hire Oprah's chef, Rosie Daley, consider input from Dr. David Heber, professor of medicine and director of the Obesity Center at UCLA. "We provided meal replacements for free and $25 a week to be weighed [it didn't matter if you lost or not] and we had a 55% dropout rate at one year," Heber says.

To Exercise Lots or Little

Exercise is the real bottom line, so say University of Pittsburgh researchers, who reported last year in the International Journal of Obesity that short bouts of exercise may enhance weight loss. Over 20 weeks, the women who dieted and engaged in three 10-minute exercise bouts a day averaged a 19.5-pound loss; those who dieted and exercised for one 30-minute session a day averaged a 14-pound loss.

But couch spuds need not cry just yet, at least not if they're about age 60 and male. In a study of older, obese men published in 1994 in the journal Metabolism, men who dieted and exercised didn't lose any more weight than those who dieted but did not exercise.

*

Diet researchers are the first to acknowledge that theirs is not an exact science. "When I attend professional meetings, this [issue of conflicting findings] comes up all the time," says Kelly Brownell, Yale professor of psychology and a veteran obesity researcher.

"Scientists are used to dealing with conflicting findings, but the public is not," he says. (And speaking of conflict, Brownell thinks the recent Lou Harris finding that 74% of Americans is puffed up; probably a third of adult Americans are sufficiently overweight to endanger their health, he says.)

So how to face the next spate of diet studies? Read them thoroughly, Brownell advises, and pay attention to comments made by experts not involved in the research.

Calories do matter, he adds, whether or not you decide to count them. "The ultimate arbiter is calories," says Brownell. Researchers thought a low-fat diet would make it easier to limit total calories, but there have been conflicting findings.

Don't focus so much on fat, calories or carbs that you neglect protein, says UCLA'S Heber. Eating too little protein could eventually lead to a lowered metabolism.

"We haven't been studying this problem for very long," adds Stevens, the food diary advocate. And it's not simple to come up with answers. Results can differ depending on the population studied, their ages and other factors.

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