By Alan Mozes

NEW YORK (Reuters Health) - For Americans seeking to shed a few pounds, a first step might be to push aside the 32-ounce mug of soda and triple-layer hamburger being set down at lunch tables across the US, a report suggests.

With more than half of all Americans clinically overweight and one out of four obese, results of an American Institute for Cancer Research (AICR) survey indicate that lack of appreciation for the importance of portion size is a significant factor.

"We tell people to measure out a standard serving on a plate and then put on another plate what you usually eat and compare those. You may be eating five or six serving sizes in your portion and maybe that's why you're overweight," noted Melanie Polk, a dietitian at AICR.

The survey was randomly administered to over 1,000 men and women across the US over the age of 18.

In particular, the AICR sought to highlight American consumer eating habits as they are affected by "value marketing"--the bang-for-your-buck advertising approach geared to offering family-sized, super-sized and over-sized value meal portions. Such sales tactics, according to the AICR, have become common in recent years in both warehouse-style grocery chains and family-style restaurants.

The investigators found that at least three out of four survey respondents thought that eating less food in general was not as important as simply avoiding certain types of foods. Also, over 25% of those polled said that they decide how much food to eat at a single sitting based on how much food they are served--making these people unofficial members of what the AICR calls the "Clean-Plate Club."

US Department of Agriculture statistics show that over the past two decades, food intake in the US has gone up almost 150 calories per day--resulting in an extra 15 pounds per year. Polk told Reuters Health that consumers need to be aware of how much they eat at home and demand that smaller food portions be made available when they eat out.

"I think that consumers need to make more of a statement," she said. "If they're looking to be able to go to a restaurant and eat for better health and a manageable weight than they have, let it be known that they would like to have smaller servings made available to them."

Polk said an effort is under way to educate consumers as to how to "eyeball" food portions. She encouraged consumers to use this practical method to develop a sense of appropriate amounts by actually measuring out servings and visually familiarizing themselves with healthy sizes. For more information, access AICR's Web site at www.aicr.org to order a brochure.