It's ok to put a little butter on your corn on the cob and add a bit more dressing to that salad. The nutrients in some vegetables are fat soluble and are absorbed much better by the body when accompanied by a little fat. A study conducted at Ohio State University, found that the absorption of nutrients was not only higher when accompanied by fats, but that it was actually minimized when the fat-free foods were eaten alone.

Previous studies have shown the same results in rats, but this study followed the nutrient absorption of human diets. It was a follow-up to a 2004 study that tracked nutrient absorption when comparing low fat salad dressings to fat-free ones. In this one, salsas and salads were served to participants with and without avocado. Absorption of beta carotene jumped by up to 18 times the amount, and lycopene jumped as much as 7 when the avocado was included, even controlling for the nutrients added by the avocado itself.

There is not yet enough research to definitively determine the optimal amount of fat per meal, but this study is that it found the best nutrient absorption (from salad), was when the food was accompanied by 28 grams of fat - 2 tablespoons of oil or about 250 extra calories. The problem that arises is the fact that adding 750 extra calories per day to the diet of the average person is a huge amount, to say nothing of the fact that 84 grams of fat is more than the recommended daily intake of 65 grams per day.

In light of this study, some nutritionists are recommending that diners take the whole meal into consideration and pair high fat foods with those that are very low in fat and calories, as well as eating a balanced diet, if maximum nutrient absorption is a priority. No time period was mentioned, but for all intents and purposes, this means you might want to have a dressing-less salad if you're going to indulge in an ice cream sundae after dinner and perhaps only a handful of berries if you're eating lasagna as a main course.

For eaters who still want to make the most of their meals, but in a less extreme way, just keep in mind that a little fat is not necessarily a bad thing, so there is no need to avoid it entirely. After all, many foods are better with a little bit of butter.

[via WSJ (subscription only)]