Snacking does not have a concrete definition. A study taken by Katherine Chaplin and Andrew Smith from the journal Appetite says, “Participants defined snacking as food or drink eaten between main meals”.
As told in the textbook Nutrition: Concepts and Controversies by Frances Sienkiewicz Sizer and Ellie Whitney, sedentary men have a recommended daily calorie intake of about 2400 kcal. For sedentary women the intake is about 2000 kcal. The average calorie intake during a meal is about 500 kilocalories leaving a range of 300-800 kilocalories for snacks between meals. Overdoing this daily allowance can cause weight gain no matter whether the snack is healthy or unhealthy.
Snacking on foods that are low in energy density, high in nutrient density, and follow the five characteristics of healthy snacking increase satiation and satiety. Sustaining a high level of satiation and satiety helps keep one within the caloric discretionary allowance, and helps one maintain a healthy body weight.
Four characteristics of a healthy diet
There are five characteristics of healthy snacking: adequacy, balance, calorie control, moderation, and variety. Together, they work to build a nutritious diet.
- Adequacy consists of consuming the correct amount of essential nutrients, fiber, and energy daily
- Balance requires not choosing any nutrient group more than other nutrient groups but rather requires one to provide enough of all the essential nutrients
- Calorie control is moderating the amount of food required to maintain a healthy weight; this entails limiting intake of fat, sugar, and salt without total self-restraint
- Variety in a diet promotes adequacy and helps eating become a more pleasurable experience
Satiation and satiety
A healthy snack leaves a feeling of both satiation and satiety.
- Satiation occurs when the brain acknowledges that enough food has been eaten; there are triggers in the body that send these signals to the brain. Sizer and Whitney say a, “Greater exposure of the mouth to food triggers increased satiation. When the stomach stretches to accommodate a meal, nerve receptors in the stomach fire, sending a signal to the brain that the stomach is full”. Healthy snacks are ones that leave the body feeling filled so that it does not continue to signal to the brain that it still wants food.
- Satiety occurs after a snack, suppressing hunger or regulating how often the body desires food. Choosing snacks that have high water content, are airy, and are high in fiber and protein causes stronger satiety signals and thus lengthens the time between meals. Fat triggers a hormone that increases satiety as well.
Nutrient density and energy density
Discretion should be used to determine whether one snack is a better choice than another based on nutrient density. The Dietary Reference Intake (DRI) establishes the amount of nutrients required daily to avoid deficiencies and allow the body to function properly. Knowing that one snack has more nutrients than another per calorie can help provide required nutrients without exceeding the discretionary calorie allowance. When analyzing the ratio of nutrients to calories in foods, the caloric level must be lower than the nutrient level in order for it to be nutrient dense. Otherwise, it could potentially cause a deficiency in an essential nutrient.
In contrast to nutrient density, energy density is the amount of calories per gram of food. For instance, snacking on two scoops (1 c.) of chocolate ice cream contains 287 calories per 132 grams making the energy density 2.17. As an alternative, one could have a snack containing celery (2 stalks), peanut butter (1 Tbsp), milk (1 c.), and an apple, which would contain similar calorie content (281 calories), but weigh 478 grams making the energy density .59. Other alternatives include salads, fruits, nuts, frozen yogurt, and cereal (1 c.) without milk. Especially when one's under pressure or frustrated, a low energy density is preferable because the food has a low ratio of calories to grams, allowing one to consume more food per calorie. Choosing a healthy snack with lower energy density will increase the amount of food one can ingest, and thus increase satiation and satiety levels, while increasing nutrient intake compared to chocolate ice cream.
There are several forms of unhealthy snacking:
- Not eating causes one form of unhealthy snacking. Evelyn Tribole and Elyse Resch claim in their book Intuitive Eating that the symptoms of starvation occur when the absence of eating is extended longer than a period of three to six hours. When the body undergoes a period of starvation, metabolism decreases and food cravings increase, causing a binge in eating high-carbohydrate foods. Neuropeptide Y (NPY) is a chemical in the brain produced during periods of starvation that triggers the need for carbohydrates. After a bout of starvation, NPY causes an eating binge of carbohydrates in which one surpasses the daily allowance, causing weight gain. Ingesting carbohydrates causes an increase in serotonin production which cancels the production of NPY. The longer the starvation period, the more intense food cravings become, making it difficult to follow the five characteristics of healthy snacking.
- Emotional eating occurs when people use food to cope with emotional triggers including boredom, procrastination, excitement, love, frustration, stress, and mild depression.
- Eating for convenience and food availability occurs when people choose to snack on energy-dense food that is readily available. In some areas the only food available is processed food, which is energy-dense and low in essential nutrients. Sizer and Whitney say, “A steady diet of such foods can easily lead to both obesity and malnutrition”. These foods are high in calories, fat, salt, and have a very low nutrient density.
There is a change in the attitude of individuals when they are told that a snack is either healthy or unhealthy. Janet Polivy and C. Peter Herman noted that individuals generally believe that whether a snack is healthy or not is based on its calorie and fat content. A “healthy” food is thought to contain few calories, and an “unhealthy” food is thought to contain many calories. Adding to that, restaurants that claim they serve “healthy” foods sometimes lead their customers to believe their food has low calorie content. Noting the perception of individuals of the healthiness of foods, snacks are perceived similarly to other foods and can be regarded as healthy or unhealthy based on their caloric content. Polivy and Herman found, in a study they performed on the perceived healthiness of a snack, that if the snack were regarded as healthy the participants ate 35% more of it than of snacks regarded as unhealthy.
Snacking frequency in adolescents
It was found in a study by Rhonda S. Sebastian, Linda E. Cleveland, and Joseph D. Goldman that snacking occasions for all age groups has increased over the last 25 years. 4,357 adolescents ages 12–19 were surveyed in order to find how the consumption of nutrients and the meeting of recommendations by the U.S. Department of Agriculture’s MyPyramid Food Guidance System are impacted by the adolescents’ snacking level.
Results: As snacking frequency increased in the adolescents, the amount of carbohydrates consumed increased along with sugar consumption. The consumption of fats and energy-adjusted proteins decreased. Increased snacking frequency positively affected the intake of vitamin A, vitamin E, vitamin C, and magnesium in boys and vitamin C in girls. Fruit intake increased as snacking frequency increased for both boys and girls. The three cup daily milk recommendation was met for boys snacking at the highest level, but girls did not meet the milk recommendation. Milk is one of the highest contributors in adolescents’ calcium consumption. Although, during the past 25 years, people have moved toward dietary habits of snacking rather than daily meals, meals generally contribute more nutrient-dense foods to a diet than snacks. In order to make up for this loss of nutrients, snack choices need to consist of nutrient-dense foods. Snacking frequency improved the chance of meeting fruit recommendations for boys and girls, milk and oil recommendations for boys, and affected the intake of all macronutrients and some micronutrients.
Benefits of snacking for older people
Claire A. Zizza, Francis A. Tayie, and Mark Lino studied the effects of snacking on older Americans. As humans age, it is known that their energy (kcal) intake decreases. The study says, “Comparisons between 25- and 70-year-olds showed declines of 1,000 to 1,200 kcal/day for men and 600 to 800 kcal/day for women”. Reasons for this decline include physiological changes, a switch in the sensation of thirst and hunger, chronic diseases, a decline in physical functioning, limited resources and social factors, namely widowhood. Healthy older persons’ low intakes of protein, carbohydrate, fat, and total energy were found to be strong predictors of mortality. These low intakes can also cause unwanted weight loss which is related to potential life-threatening physical limitations. This loss of weight can be prevented by instituting a proper diet.
Results: In a sample of 2,002 older people, ages 65+, 84% were ambitious snackers. Nonsnackers ingested an average of 1,466 kilocalories daily while snackers ingested an average of 1,718 kcal. The US Department of Agriculture’s MyPyramid states that the recommended consumption of energy for older adults is 1,600 kcal. The study shows that, “In this age group, snacking contributed approximately a quarter of their daily energy and carbohydrate intakes and a fifth of their daily fat intake”. Adding healthful snacking to the dietary behavior of older adults in Zizza, Tayie, and Lino’s study proved to increase their total energy intake preventing inadequate diets.
A study done by SL Colles, JB Dixon, and PE O’Brien on snacking at night relates obesity, binge eating disorder (BED), and psychological stress to night eating syndrome (NES). This syndrome constitutes a pattern of eating where most food is consumed late in the day and at night, sometimes including waking up during the night to snack. It causes morning anorexia and evening hyperphagia and insomnia. This condition is observed most frequently in overweight and obese people. Being a recent syndrome to emerge, the study says, “It is currently unclear whether NES, as a discrete condition, is associated with emotional distress, impairment or disability, and thereby represents an eating disorder of clinical significance”. It may just be a behavioral condition linked to obesity and weight gain. The study was conducted by distributing surveys to people ages 18–70 that had not undergone previous bariatric surgery.
Results: NES and BMI are positively related, meaning that the generalized belief that NES is associated with overweight and obese individuals has a stronger basis for being true. To relate NES with BED the study showed, “[Binge-eaters] were almost seven times more likely to manifest NES than non-[binge-eaters]”. This showed that it is common for individuals that show traits of NES also have BED. The results, however, for the relation between NES and psychological distress were found to contrast those for BED. Individuals who exhibited traits of NES showed low psychological distress, whereas those who were binge-eaters showed high psychological distress. This showed that those who exhibited signs of BED were more likely to be depressed and concerned about their weight. This study was the first to observe differences between those who did and did not wake up for nocturnal snacks. The study shows that, “Frequent nocturnal snackers reported higher symptoms of depression and hunger . . . compared to the NES who did not wake to eat”. This shows clinical significance and that nocturnal snackers have a more severe impairment than individuals with NES.
The effect of watching television on snacking
Harriëtte M. Snoek, Tatjana van Strien, Jan M.A.M. Janssens, and Rutger C.M.E. Engels recorded a study of the effect of television viewing on adolescents’ snacking. They explain three theories on the relationship between eating behavior and being overweight and how they relate to watching television. The first theory centers on external eating declaring that some people are more sensitive to food cues than others. Food cues found on television include food advertisements. Certain people can be influenced by these cues regardless of their state of hunger and satiety. The second theory is the restraint theory, which states, “Dieting can lead to overeating”. Weight-related advertisements and images of a stereotypical attractive female on television can generate negative feelings toward the body and low self-esteem in individuals who are dieting causing them to overeat. The third theory is known as the psychosomatic theory, which deals with those who eat in response to their emotions. In these individuals, negative emotions cause excessive eating rather than the normal response of appetite loss. The study used 10,087 Dutch adolescents 11–16 years of age. Snacking was measured as, “The number of sweet and/or savory snacks respondents usually ate per day”. The participants were required to rate their frequency of television viewing and measure their eating behavior through a questionnaire.
Results: Participants who received a high score under the external eating category of the questionnaire ate more snacks than those who did not; those who received a high score under the restrained eating category ate fewer snacks than those who did not; and those who received a high score under the emotional eating category ate more snacks than those who did not. The study showed that external and emotional eaters were more likely to snack when influenced by television and restrained eaters were less likely to snack due to the influence of television. The study shares that, “The interaction between [television viewing], emotional eating and snacking was only significant for boys,” possibly due to the, “inadequacy in dealing with negative emotions,” which might be a personality trait that is different from men to women.
- Chaplin, Katherine and Andrew Smith. “Definitions and Perceptions of Snacking.” Appetite. (2006): 260. Print.
- "Definition of Snack at Dictionary.com". Retrieved 2011-03-13.
- Sizer, Fances Sienkiewicz and Ellie Whitney. Nutrition: Concepts and Controversies. United States: Wadsworth, Cengage Learning, 2011. Print.
- Tribole, Evelyn and Elyse Resch. Intuitive Eating: A Revolutionary Program That Works. New York: St. Martin’s Griffin, 2003. Print.
- Polivy, Janet and C. Peter Herman. “Perceived Healthiness of Food. If it’s Healthy, You Can Eat More!” Appetite. (2009): 340-344. Print.
- Sebastian, Rhonda S., Linda E. Cleveland, and Joseph D. Goldman. “Effect of Snacking Frequency on Adolescents’ Dietary Intakes and Meeting National Recommendations.” Journal of Adolescent Health. (2008): 503-511. Print.
- Zizza, Claire A., Francis A. Tayie, and Mark Lino. “Benefits of Snacking in Older Americans.” Journal of the American Dietetic Association. (2007): 800-806. Print.
- Colles, SL, JB Dixon, and PE O’Brien. “Night Eating Syndrome and Nocturnal Snacking: Association with Obesity, Binge Eating and Psychological Distress.” International Journal of Obesity. (2007): 1722-1730. Print.
- Snoek, Harriette M., Tatjana van Strien, Jan M.A.M. Janssens, and Rutger C.M.E. Engels. “The Effect of Television Viewing on Adolescents’ Snacking: Individual Differences Explained by External, Restrained and Emotional Eating.” Journal of Adolescent Health. (2006): 448-451. Print.
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