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The small town of Tiburon, Calif., initiated a nationwide wave of action when its restaurateurs voluntarily stopped using foods containing trans fats. The wave crossed the nation and broke over New York City when, in December 2006, its Board of Health approved a ban on restaurant foods containing >0.5 g of trans fat per serving. Now other U.S. cities and states are considering similar proposals.1
Meir Stampfer, MD, DrPH, professor of epidemiology and nutrition at Harvard School of Public Health in Boston, applauds these developments. "My colleagues and I from the Harvard School of Public Health estimate, from laboratory and epidemiological studies, that between 72,000 and 228,000 heart attacks could be prevented each year in America if industrially produced trans fats were eliminated from our diet," Stampfer says.2
Trans fats are partially hydrogenated oils commonly used for frying foods, to prolong shelf life in prepackaged foods, and in the manufacture of margarines and shortenings. Trans fats also raise LDL cholesterol, lower HDL cholesterol, and may increase risk of sudden death and diabetes, explains Stampfer. "Replacing trans fats with healthy fats will almost certainly prevent many thousands of premature deaths each year," concurs Walter C. Willett, MD, DrPH, chair of the department of nutrition at Harvard School of Public Health.
And, Willett says, "There is now strongly suggestive information from both epidemiological and animal studies that these changes in type of fat will have a beneficial effect on obesity rates."
TRANS FATS AND WAIST/WEIGHT GAIN
Research suggesting that trans fats carry the additional risk of increasing abdominal fat and body weight is an emerging area of study:
But at this point, "the data are inadequate" to determine if a definitive link exists between trans fat intake and weight gain, contends Tufts University's Alice Lichtenstein, DSc.
As Gershoff professor of nutrition science at Tufts' Friedman School of Nutrition Science and Policy and director of Tufts' Cardiovascular Nutrition Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging in Boston, Lichtenstein agrees that decreasing intake of trans fats "is a move in the right direction," and that any measure to encourage the phaseout of these fats without increasing intake of saturated fats "is probably a good idea."
But, she notes, even if research definitively identifies trans fat intake as contributory to weight gain, "we would be misguided to assume this would solve our obesity epidemic."
CALORIE FOR CALORIE, FAT IS FAT
Weight control goes beyond trans fat consumption; it requires attention to calorie intake, portion size, and increased physical activity. "If you sit down and eat the whole basket of bread before your meal begins," notes American Dietetic Association spokesperson Bonnie Taub-Dix, AM, RD, CDN, "this will contribute to obesity even if there is not a gram of fat in that bread."
Patients need to understand that foods listed as trans fat-free may not be fat-free. Substituting saturated fat for trans fat, she adds, "does not necessarily make for a healthy product." Nor does it cut that food's overall calories.
Assessing the fat content of a meal, with the aim of limiting fats and overall calories, is a valuable dietary practice. Taub-Dix suggests avoiding crackers, instant soups, donuts, muffins, cakes, mixes, and frozen foods that may contain trans fats and pack a high caloric punch. She tells patients to order restaurant dishes prepared with healthier fats and more fruits and vegetables—especially those prepared as close to their natural state as possible—and to ask for any high-fat, high-calorie sauces to be served on the side.
"I've been in practice for over 30 years," recalls Taub-Dix, "and I've never had a patient come to me because they were overweight from eating too many vegetables."
CALORIC LABELING
An important move that has not garnered enough media attention is New York City's March 1, 2007, requirement that restaurants with standard menu items list calorie information at the point of purchase, says Lichtenstein. Arizona, California, Connecticut, Illinois, and New Jersey are among the states currently considering similar requirements for national chain restaurants.1
Customers at McDonald's, for instance, may opt for small rather than large fries if they see it saves them 290 calories. Or they may pass on the 32 oz chocolate triple-thick shake when they find it packs a walloping 1,160 calories. A McDonald's Caesar salad contains just 90 calories, but adding crispy chicken ups the count to 300 calories and dousing the lettuce with creamy Caesar dressing heaps on an additional 190 calories.7
Whether these caloric labeling requirements will affect consumers' ordering patterns or influence obesity trends in the U.S. "is still the $64,000 question," Lichtenstein remarks, but such labeling "is unlikely to have an adverse effect."
Obesity comes from "people eating too much food and burning too few
calories," Lichtenstein emphasizes, and she warns that an exclusive
focus on nutritional "hot items"—such as trans
fats—sometimes can overshadow this reality. 
Footnotes
Many chain restaurant Web sites list the caloric content of their products. In addition, these Web sites offer calorie counts for restaurant dishes and other foods: www.calorieking.com/foods/ www.nutritiondata.com/ www.chowbaby.com/fastfood/fast_food_nutrition.asp
For more on differentiating fats in foods, see DOC News, November 2006, page 10.
References
2. Mozaffarian D, Katan MB, Ascherio A, et al.: Trans fatty acids and
cardiovascular disease. N Engl J Med 354: 1601–1613, 2006.
3. Koh-Banerjee P, Chu NF, Spiegelman D, et al.: Prospective study of
the association of changes in dietary intake, physical activity, alcohol
consumption, and smoking with 9-y gain in waist circumference among 16,587
U.S. men. Am J Clin Nutr 78:719–727, 2003.
4. Kavanagh K, Jones K, Sawyer J, et al.: Trans fat diet induces insulin resistance in monkeys: June 12, 2006, presentation at the 66th Annual Scientific Sessions of the American Diabetes Association, Washington, D.C. Diabetes 55 (Suppl. 1): A77, 2006.
5. EurekAlert: Trans fat leads to weight gain even on same total calories, animal study shows. Available online at www.eurekalert.org/pub_releases/2006-06/wfub-tfl060506. php. Accessed February 23, 2007.
6. Field AE, Willett WC, Lissner L, et al.: Dietary fat and weight gain among women in the Nurses' Health Study: October 21 presentation at NAASO, The Obesity Society's 2006 Annual Scientific Meeting, Boston.
7. CalorieLab: Calorie counter. Available online at www.calorielab.com/mcdonalds.html. Accessed February 22, 2007.
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