NEW ORLEANS — Beverages represent 40% to 50% of calories consumed when snacking, but consumers often overlook these calories as a part of their overall energy intake, Richard Mattes, professor of foods and nutrition at Purdue University, said at the Institute of Food Technologists meeting on June 13.

“Food form is an important dimension of snacking we have to pay attention to,” Mr. Mattes said.

Additionally, about one-fourth of the energy in a consumer’s day comes from snacking. While these facts are clear, there is much gray area when it comes to specifically defining snacking for research purposes or whether or not snacking contributes to obesity. While different studies yield different conclusions on whether or not increased snacking causes weight gain, Mr. Mattes said it appears weight gain has more to do with how well eating occasions and overall calorie consumption is planned.

“Unplanned eating leads to unexpected results,” Mr. Mattes said.

When it comes to defining snacking, G. Harvey Anderson, professor of nutritional sciences, physiology and medical sciences at the University of Toronto, said there are all sorts of definitions out there based on aspects such as eating frequently, the consumption of nutrient-poor foods, the time of day and the specific foods consumed. But ultimately the definition of snacking is determined by the consumer.

Because there is no universal definition of snacking, Mr. Anderson said it becomes complicated to interpret and compare data on snacking. Additionally, dietary guidance cannot be given, and snacking behavior is not a focus of research and not well understood due to the lack of definition. As a result, there is a lack of data on the effects of snacking such as satiety, food intake, nutrient intake, metabolic health, mood, alertness and memory.

Mr. Mattes said nearly 100% of consumers report snacking. Nancy Auestad of the National Dairy Council said 25% of consumers said they try to eat mini-meals throughout the day, one-third of consumers said they are eating a healthy snack everyday, and two-thirds of consumers are reporting two or more snacks of any kind per day.

Mr. Anderson also said prohibiting children from eating foods often classified as “junk” food is likely to be counter-productive as such children often eat more calories after lunch than children who had some less healthy snacks.