According to the CSPI, the nutrition labels on coffee creamers could be misleading consumers into thinking that they are a healthier option than real milk.
"The nutrition label on the Coffee-mate in your office kitchen might list 10 calories and just a half a gram of saturated fat.
Those sound like reassuringly low levels of both.
But use a more realistic tablespoon-size serving instead of the miserly teaspoon the Food and Drug Administration allows-and unround the rounded down numbers on the label-and you're looking at 45 calories and three grams of heart-harmful saturated fat," the CSPI said.
Given that the average daily coffee consumption is around three or four servings, many US office workers could have "stealthily consumed half a day's saturated fat" , the consumer advocacy center claims.
The CSPI carried out its assessment of the fat content of the most popular office creamers for an article in its monthly newsletter, and is critical of most of the popular brands.
While it points out that Nestlé (the owner of the Coffee-mate brand) does produce a number of low-fat variants, as do other creamer producers, it warns that this is no guarantee that the product is fat-free.
"If a food has less than 0.5 grams of fat (trans, saturated, or total) per serving, labels can round the number to zero."
While the CSPI report stated that a flat teaspoon has 0.27 grams of saturated fat, a spokesperson for Nestle told FoodNavigator-USA.com that CSPI had been given some incorrect figures relating to serving size.
She said company was working on providing the correct figures, but these were not available at time of publication.
However the spokesperson added that the practice of rounding down nutrient content is in line with FDA guidelines.
"Every product in the United States follows the same guidelines," she said - and these guidelines are not based on simple arithmetic but on a complex set of rounding rules depending on nutritional profile.
However in its assessment of Nestle's creamer brands, the CSPI said that the liquid version was "worse" than all of them.
"Instead of using the coconut and palm kernel oils Nestlé employs in the powdered version, the liquid versions use partially hydrogenated soybean or cottonseed oil," the CSPI said.
The Dietary Guidelines for Americans from 2005 recommends limiting dietary intake of saturated and trans-fats to less than 20g a day.
Saturated and trans-fats have been linked to health risks such as coronary heart disease.
For the CSPI, however, it is as much the label as the formulation of the creamers that are to blame.
"Anyone glancing at the Nutrition Facts label for most of these coffee creamers would have a false sense of security," said CSPI nutrition director Bonnie Liebman.
The portion size - a teaspoon, instead of the more likely tablespoon, the equivalent of three teaspoons - is particularly misleading, according to the Liebman, one of the authors of the report.
"The serving sizes listed on creamer containers are designed to whiten a six-ounce cup of coffee.
That's a teacup.
Most mugs hold eight to 12 ounces.
By the time you consider large mugs, imprecise pouring, and seconds or thirds, you may be getting much more from that creamer than you think."
However the Nestle spokesperson told FoodNavigator-USA.com that Food and Drug Administration establishes different serving standards - and the teaspoon is a standard size.
"Serving size varies by consumer," she said.
"It depends on the size of the coffee cup and taste preferences".
The only creamers to pass the CSPI's labeling assessment were International Delight Fat Free (with zero saturated or trans-fats) and Silk liquid creamers (with zero saturated and 0.5g of trans-fat).
In contrast, the full-fat International Delight brand contains 2.2g of saturated and trans-fat, according to CSPI estimates.
And US office workers could do a lot worse than opting for good old fashioned milk in their coffee, CSPI concludes: fat-free, one per cent, two percent and even whole milk have no more than about 0.6g of saturated and trans-fat, according to the researchers.