NUTRITIONISTS and researchers have reacted positively to the news that General Mills has added whole grains to breakfast cereals that did not include them before. But the praise is not without reservation: the fiber content of many of the cereals has increased very little, if at all.

"Whole grains" are buzz words for 2005. One market research firm, Mintel, has declared them the ingredient of the year. On Monday, Post cereals announced its lineup of whole grain cereals. The rush brings back memories of the late 1980's and the oat bran craze , which lost steam as soon as oat bran potato chips appeared on the market.

But whole grains are different. They are not unnatural additions to food, the way oat bran was for most products. White flour did not become popular until after the Civil War, when the invention of the steel roller mill made the refining process cheap. But the process of refining grains strips them of much of their vitamin, mineral and fiber content. That is why ready-to-eat cereals are fortified with many - though not all - of those lost vitamins and minerals. Fiber is not added back.

The whole grain movement received an important boost when the federal dietary guidelines, released last month, suggested that half of the recommended grain servings consumed by Americans be whole grains, particularly because of their fiber content. Whole grains now make up only 5 percent of the grains eaten by Americans.

But based on information appearing on two General Mills Web sites, 28 of the company's 52 cereals contain the same level of fiber they had previously; two have one gram less than they had before the reformulation; and 14 have moved up one gram, with 11 of those going to one from zero. In fact, a total of 22 cereals have just one gram of fiber. Five cereals still have no fiber: Boo Berry, Frosted Chex, Honey Nut Chex, Franken Berry and Shrek. Cereals that were always 100 percent whole grain - like Total, Wheat Chex and Wheaties - would not be expected to have more fiber.

The information on the "before" cereals came from a General Mills Web site, www.bellinstitute.com/nutrition/pn/all.htm, which a company spokeswoman said was five years out of date and has been shut down. She refused to provide numbers for any of the cereals as they were before the reformulation. Current nutritional figures are available at www.generalmills.com/corporate/brands.

Only 24 of the current cereals contain two or more grams of fiber and would meet the standards of the Whole Grains Council, a trade association dedicated to increasing the consumption of whole grains. According to the council's Web site, www.wholegrainscouncil.org, "a true whole grain product will have at least two grams of fiber per serving and often four to five grams or more." The General Mills cereal with the most fiber in a serving is Fiber One, with 14 grams in a half cup serving.

If there is a choice between refined grains and whole grains, whole grains are indeed better, and the new versions of the General Mills cereals contain some of those other important missing micronutrients - antioxidants, phytochemicals or disease fighting plant chemicals - and minerals like selenium and chromium, which can reduce the risk of heart disease, may help in weight maintenance and may reduce the risk of diabetes and other chronic illnesses.

"It's a step in the right direction," said Dr. Meir Stampfer, a professor of epidemiology and nutrition at the Harvard School of Public Health.

Bonnie Liebman, the director of nutrition at the Center for Science in the Public Interest, a nutrition advocacy group, which is often critical of government and the food industry, also considers the reformulation of the cereal an improvement. But she does not want people to think that the use of whole grains has magically made the cereals an excellent source of nutrition.

"It's important for people to realize that using whole grains in breakfast cereals does not turn them into health foods," she said. "Many are still breakfast candy, almost half sugar."

The cereal company wants the public to be aware that it is selling whole grains, not fiber. Susan Crockett, the senior director at the Bell Institute of Health and Nutrition of General Mills, said she knows that some people, including health professionals "think whole grain and fiber are the same thing." But she said the benefits of whole grain have to do with "the synergy of the components."

The company's Web site makes the case again, stating, "whole grain is more than fiber."

Dr. Joanne L. Slavin, a professor of food science and nutrition at the University of Minnesota, said the absence of significant levels of fiber "is a bit of a disconnect because people look for fiber, and when they don't see it, it's confusing." She added: "If this stuff is mostly sugar, we are potentially confusing or misleading people if they think it's totally healthy. But it's probably better than a crummy Danish that's been sitting in the package for three weeks."

Dr. Slavin said she has worked with General Mills and likes the whole grain message, but she said, "I'm also a fiber person, and I'd like those whole grains to have more fiber in them."

The level of fiber in whole grains is dependent on the variety: whole wheat and oats naturally have more fiber than brown rice. But the level of whole grains in a ready-to-eat cereal, no matter the brand, is also dependent on the sugar content. The more sugar, the less grain and fiber. Just compare the various kinds of Cheerios: a 30 gram (about an ounce) serving of unsweetened Cheerios contains one gram of sugar, three grams of dietary fiber; the same size serving of the sweetened Apple Cinnamon Cheerios and Frosted Cheerios, each with 13 grams of sugar, contains just one gram of fiber.

Dr. Barbara Schneeman, the director of nutrition products, labeling and dietary supplements at the Food and Drug Administration, said, "the reason to include whole grain products in the diet is to increase the fiber content." She suggested that consumers check under daily value in the far right column of a package's nutrition facts panel to find out if a food is high or low in fiber. "If the daily value is 5 percent fiber, that is low," she explained, while "20 percent or more is high. Look at the fiber content and the added sugar content, and then make comparisons."

The guidelines recommend 28 grams of fiber for most women daily, 35 for most men.

Though the Food and Drug Administration has not established a definition for good and excellent sources of whole grain, General Mills says cereals that have 8 to 16 grams of whole grains can be called good sources. And those that have 16 or more grams of whole grains can be called excellent, which is how the company describes the cereals on its labels.

A spokeswoman for the Food and Drug Administration said that it "would have to look at the entire package and context in which it appears to see if the statements are false and misleading." Last May, General Mills asked the agency to create a federal standard based on the levels the company is using.

Whether General Mills cereals are good or excellent sources of nutrition, Dr. Stampfer of Harvard said that adding whole grains to a cereal like Trix "doesn't make Trix a health food." He added: "I hope I am not being interpreted saying that Trix is a good healthy choice for eating. Would I recommend Trix compared to steel-cut oats as a choice for breakfast? No."