The "food pyramid" is getting squashed by the U.S. Department of Agriculture (USDA) this week.

Gone will be the massive base slab of breads, pasta and grains—and the suggestive "sparing" point of sweets and fats—of the 1990s. Gone also will be the confounding rainbow-striped "MyPyramid" with its online personal food plans introduced in 2005 during the George W. Bush administration. In their place will be a new circular chart to depict the government's recommended model for American meals.

The revelation is, of course, not one of geometry but one of proportions. In the new U.S. dietary model, fruits and vegetables are taking center stage, likely comprising a good half of the picture.

The new chart, to be unveiled Thursday morning, has been kept under wraps. But reports from those who have seen it describe it as a dinner plate with proportions of various servings mapped out in colorful slices and accompanied by a small white circle—to represent a glass of milk or other dairy product.

The classic tiered food pyramid was recognized by nutritionists as a misstep almost as soon as it debuted in 1992. "More and more research has shown that the USDA pyramid is grossly flawed …" Walter Willett, chair of Harvard University's School of Public Health's Department of Nutrition, and Meir Stampfer, a professor of medicine at Harvard Medical School, wrote back in 2003, "…the pyramid provides misleading guidance."

Is the new food chart headed in the right direction—and will it actually help Americans eat better? To find out, we spoke with Marion Nestle, a professor of nutrition, food studies and public health at New York University and author of several books, including What to Eat (North Point Press, 2006). And as Nestle pointed out in a 2007 article for Scientific American, "Nutrition advice seems endlessly mired in scientific argument, the self-interest of food companies and compromises by government regulators." So how does she think the new USDA model looks?

[An edited transcript of the interview follows.]

Why does the food pyramid need to go?
Because the 2005 pyramid had no food on it. It was completely un-teachable, and you needed a computer to understand it.

What about the older food pyramid version with the starches on the bottom?
I liked it much better. That one was the result of a very long research project. The message they wanted to convey was it was better to eat more of some things than others.

But there were two major causes for argument: political and nutritional. The political one made clear that meats and junk foods were to be consumed, but in smaller portions than other foods. The nutritional flaw was that it had grains at the bottom and recommended six to 11 servings. The serving sizes have grown to tremendous proportions, and no one knew what serving sizes were. One bagel is six servings, but no one knew that.

What do you think of the dinner plate idea?
Well, it's banal, but it works. It's very easily teachable.

I don't think it goes far enough, but it's certainly headed in the right direction. I think it's actually pretty great. You can show someone and say, "Your dinner plate should look like this." And they'll say you're out of your mind. For most of us meat has made up most of the meal. This is a huge change, and I think it's courageous. Nobody profits from fruits and vegetables—except for the growers, and they don't make very much. All the money is in processing food and the intermediate steps.

Are these new recommendations based on good science—about diet and about how people are likely to use the chart?
They're certainly based more on science than they ever have been before. They're from the new USDA dietary guidelines, which were released earlier this year. So they have a research basis, and this is meant to put this research basis forward.

If you were to design the dietary chart, what would it look like?

This is trivial, but I hate the "protein" sector. I'm a nutritionist, and it's a switch from food to nutrients, which is always a mistake—it's just wrong. Grains and dairy, which have their own sectors, are a very important source of protein. They didn't want to call it the meat group in part because the meat industry has really been trying to equate meat with protein, and they didn't want to minimize meat and have smaller sectors for beans, poultry and fish. This is their way of doing an "eat less meat" move without actually saying it.

Do you think this new model will really influence people's diets and help them eat better?
It remains to be seen. It depends on how they're used, how big of a public relations campaign it has, and if it generates controversy. If it doesn't generate controversy, nobody will know anything about it. From the standpoint of dieticians sitting in their offices talking to a patient who has diabetes, it should make it much easier.

Why does there always seem to be so much disagreement about nutrition?

My recommendations are: eat less; move more; eat plenty of fruits and vegetables; and avoid too much junk food. Who profits from that? We have a food system that's overabundant. And for food companies it's very difficult to sell food in that environment and meet Wall Street targets. If you read between the lines of this new model, it says: stop drinking soda. If I were a soda company, I would be stressed. But fortunately, I'm not.