Consumption of unhealthy snack food, i.e. junk food, is continually increasing and contributes to obesity, especially among children.

However, it is not always easy to identify which snacks are healthy and which are pure junk. Consumers need guidelines.

Luckily, James W. Anderson, MD, FACN, CNS and Katy Patterson, BS, two researchers, provided several definitions in an article they wrote for Journal of the American College of Nutrition, (Vol. 24, No. 3, 155-156 (2005)).

Definining Healthy Snacks
They stated: "Excellent choices for snacks are high in nutritional value and low in energy such as vegetables, fruits and low-fat dairy foods. Less desirable choices are low in nutritional value and high in energy such as candy, chips, cookies, crackers and snacks." By Energy, Anderson and Patterson mean Calories, or kcal, in scientific terms.

Measuring Healthy Snacks
Of course, the definition above requires a quantative measure, which is why the researchers provided specific numbers to indicate whether a snack was healthy or junk. All measures were made using 1oz. of a particular snacks.

So for example, Fruits, a healthy snack, deliver an average of 16 kcal/ounce with one serving providing these: 80 kcal; 1.0 g protein; 0.6 grams total fat; 15.8 g sugar; 3.0 g fiber; 2.9 mg sodium; and 283 mg potassium.

On the other hand, Candy bars, an unhealthy snack, provide these average values per ounce: 139 kcal; 2.2 g protein, 7 g fat; 15 g sugar; and 0.6 g fiber.

In general, the authors conclude that for healthy snacks: "Consensus nutrition guidelines suggest these approximate goals per 100 kcal (based on intake of 2000 kcal/d): ≥2.5 g protein; <3 g fat; <25% of energy from added sugars; >1.4 g fiber; <120 mg sodium; >230 mg potassium; and >60 mg calcium. Most junk foods meet only one or two of seven (average = 22%) of these nutrition guidelines whereas most vegetables, fruits and low-fat dairy foods meet five to seven (87%) of the guidelines."