what science says about snacking

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What Science Says about Snacking Experts explore snack factors from eating frequencies to food choices.

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Page 1: What Science Says About Snacking

What Science Says about SnackingExperts explore snack factors from eating frequencies to food choices.

Page 2: What Science Says About Snacking

American dining may have evolved from Old World custom into the "three square meals" tradition of the 20th century, but today's consumers are snackers. In

fact, over the last four decades, more Americans have traded in meals for snacks.

Page 3: What Science Says About Snacking

Between-meal noshing supplies nearly one-quarter of daily calories, earning snacks the status of "fourth

meal." What's more, since the late 1970s, daily calorie intake has increased among men and women, with the

majority of additional calories consumed between meals.

Page 4: What Science Says About Snacking

A 2011 report from the U.S. Department of Agriculture claims Americans snack twice as often as they did in the late 1970s, although newer analysis of the data

suggests the frequency of snacks has stayed the same while total calories have increased.

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These figures have led some experts to ask how snacking affects

body weight and other health concerns.

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How and Why We Snack

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While some people eat between meals because they hold a vague notion that frequent eating is healthful, others report snacking to satisfy cravings for sweet or salty foods, prevent or relieve hunger, boost nutrient

intakes, control weight, rev their metabolic rates, pass the time, deal with unsettling emotions or replace

meals.

Page 8: What Science Says About Snacking

According to a 2014 Nielsen report, 41 percent of North American respondents ate snacks instead of dinner at least once in the previous 30 days. The favorite snacks

in North America are chips, chocolate and cheese, according to the report.

Page 9: What Science Says About Snacking

Fresh fruit landed fifth in popularity, with 55 percent of survey respondents reporting they ate fresh fruit for a snack at least once in the previous 30 days. A separate

study reported that adolescents who snacked most often were the most likely to skip meals. All-day

grazing and frequent snacking instead of structured meals and snacks may be side effects of today's

on-the-go lifestyle.

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Does Snacking Affect Weight?

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Snacking may help control appetite, or it may contribute to recreational eating and excess calories. Research supports both opposing views. Beginning in

the 1960s, studies noted that people who ate the fewest number of times during the day had the

greatest amount of excess body weight, leading many health professionals to recommend frequent eating as

a weight-loss tool.

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More recently, researchers have challenged the idea that eating frequently aids weight control. A widely

recognized problem in diet studies is underreporting of food and calorie intake by some participants. When

researchers removed data of people they suspected gave faulty information, the results suggested that the more

often someone ate, the higher his or her body mass index would be. Spanish researchers found that people who

identified themselves as usual snackers were most likely to gain significant weight during the study's 4½-year

follow-up period. Plus, they were nearly 70 percent more likely to become obese.

Page 13: What Science Says About Snacking

Among teen girls, eating frequently at the beginning of the study predicted less body fat a decade later. And a study of nearly 2,700 men and women in their 40s and 50s found those who consumed solid food six or more

times in 24 hours took in fewer calories and had a lower mean BMI compared to participants who ate solid

foods fewer than four times daily.

Page 14: What Science Says About Snacking

Conflicting data may be the result of many factors, such as the way researchers defined a snack or eating

occasion, whether or not caloric beverages were included in the analyses and underreporting of food, beverage and calorie intake, which can make dietary assessment tools invalid. Reverse causality also may

be at play, meaning that some people with higher BMIs may choose to eat less frequently in attempt to lose

eight — not that they are heavier because they eat less often.

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Though population studies show inconsistent results, randomized intervention trials allowing subjects to choose what they eat generally

show no effect on body weight. Of five short-term studies comparing high and low eating frequencies, only one showed a slight advantage when subjects consumed more meals and snacks. Sixteen adults with high

cholesterol levels consumed the foods they typically ate, but either as three or nine meals daily for four weeks. Participants eating more often

lost an average of 0.9 pounds, while those on the less-frequent meal pattern dropped only 0.2 pounds. In a two-month weight-loss program combining meal replacements and regular food, weight loss was the

same whether participants consumed three daily meals or three meals plus a bedtime snack.

Page 16: What Science Says About Snacking

Although some dieters snack to boost their metabolic rates, research suggests these efforts are in vain. Studies that examine data for up to 48

hours after eating find that the jump in metabolic rate or the thermic effect of food is not dependent on meal frequency. Rather, overall

metabolic rate is similar when a specific amount of food is eaten during few or many occasions. Since frequent eating doesn't appear to burn more calories, researchers looked at the opposite side of the energy

balance equation: Does frequent eating cause people to consume fewer calories? One review found a slight benefit to appetite control when

eating six meals per day compared to three, and that eating fewer than three meals per day is unfavorable for appetite control.

Page 17: What Science Says About Snacking

Both the Evidence Analysis Library of the Academy of Nutrition and Dietetics and experts at a 2009

symposium on eating frequency and energy balance concluded that scientific evidence pointing to an ideal

eating frequency for weight control doesn't exist at this time.

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Snacking on Other Metabolic Effects

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Eating frequency has the potential to affect metabolic parameters other than weight and body fat. In the

two-month meal replacement study previously mentioned, there were no differences in cholesterol or triglyceride levels between those eating either three or

four times daily.

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However, when seven healthy men consumed identical diets as either three daily meals or 17 daily "nibbles"

(defined as smaller than a regular snack) for two weeks, cholesterol measurements were better with the

nibbling pattern. This study has limitations due to its small sample size, so more research is needed to

support the findings.

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Additionally, two single-day studies found improvements in blood sugar and lipids when adults with Type 2 diabetes ate more often. But a four-week study among people with Type 2 diabetes found no

such advantage when comparing nine small meals to three larger meals and one snack.

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Even if long-term benefits were likely, would many people want to eat up to 17 times per day?

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Snacking and Diet Quality

Page 24: What Science Says About Snacking

Snacks may boost diet quality or lead to excess intakes of solid fats, added sugars and sodium. Although

experts debate the health value of snacking, nearly all agree that the type of snack matters. A study of 233

adults in a worksite wellness program found that total snacking calories and frequency of snacking were

unrelated to diet quality or BMI.

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However, the choice of snack foods affected both. The percentage of snacking calories from nuts, fruit and

100-percent fruit juice was related to better diet quality, while percentage of snacking calories from

sweets and sugar-sweetened beverages was related to poor diet quality. Eating vegetables as snacks was associated with lower BMI, and eating sweets was

associated with higher BMI.

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While there is considerable interest in eating frequency, there is no consensus regarding an ideal

pattern. It may be that meal and snack quality is more important than frequency of eating and that consumers

can benefit from any number of meal patterns. As research into these factors continues, the best pattern may be the one most suitable to a person's individual

lifestyle.

Page 27: What Science Says About Snacking

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