this might say it best
All food provides calories. All calories provide energy. But not all calories come with a full complement of extra benefits, such as amino acids, fatty acids, fiber, vitamins, and minerals.
Some foods are said to give you "empty calories." This term has nothing to do with the calorie's energy potential or with calories having a hole in the middle. It describes a "naked calorie," one with no extra benefits.
The best-known empty-calorie foods are table sugar and ethanol (the kind of alcohol found in beer, wine, and spirits). On their own, sugar and ethanol give you energy — but no nutrients. People who abuse alcohol aren't always thin, but the fact that they often substitute alcohol for food almost always leads to nutritional deficiencies, most commonly a deficiency of thiamin (vitamin B1).
Of course, it's only fair to point out that both sugar and alcohol are often ingredients in foods that do provide other nutrients. For example, sugar is found in bread, and alcohol is found in beer — two very different foods that both have calcium, phosphorous, iron, potassium, sodium, and B vitamins.
In the United States, some people are malnourished because they cannot afford enough food to get the nutrients they need. The school lunch program — started by President Franklin Delano Roosevelt in 1935 and expanded by almost every president, Republican and Democrat, since then — has been a largely successful attempt to prevent malnutrition among poor schoolchildren.