Published June 25, 2010
Teenagers who have snacks throughout the day are less likely to be overweight or obese than their peers who limit themselves to larger meals, a new study suggests.
The study, of 5,800 U.S. teenagers included in a government health survey, found that rates of obesity, and abdominal obesity specifically, declined with the number of snacks kids had each day.
Of teens who said they did not snack, 39 percent were overweight or obese; that compared with rates of 30 percent, 28 percent and 22 percent among their peers who consumed two, three or four or more snacks in a day, respectively.
Similarly, the rate of abdominal obesity was 24 percent among non-snacking teens, while the lowest rate — 11 percent — was seen in the four-snack-a-day group.
The findings, published in the American Journal of Clinical Nutrition, add to a conflicting body of research on whether snacking is good or bad for the waistline.
Some studies have linked snacking to lower body weight, while others have not. And while there is some evidence of metabolic benefits in having more-frequent, smaller meals throughout the day — in managing cholesterol levels and diabetes, for instance — it is not clear whether such eating patterns help prevent weight gain or promote weight loss.
What's more, if people do not balance their snacking by eating less at meal time, that between-meal "grazing" could help pack on the pounds.
In one recent study, researchers found that U.S. children increased their snacking between 1977 and 2006 — downing an average of three snacks per day in the most recent year. Desserts and sugary drinks were the top sources of snack calories, the researchers found, and they speculated that this trend "toward constant eating" may be one of the reasons for the rise in childhood obesity.
In the new study, however, "snackers" were the thinner ones.
When the researchers accounted for a number of other factors — including exercise habits (active teens may need more snacks for energy), time spent in front of the TV or computer, ethnicity and family income — snacking itself remained linked to a lower risk of being overweight or obese.
Teens who reported having four or more snacks in a day were 60 percent less likely to be overweight or obese, and similarly less likely to have abdominal obesity, than their peers who reported no snacking.
The researchers also looked at whether the teens had been trying to lose weight. Logically, people trying to shed pounds might cut out snacks, and that could account for the higher rate of obesity among non-snackers, explained lead researcher Dr. Debra R. Keast, of Food & Nutrition Database Research Inc., in Okemos, Michigan.
But weight-loss attempts did not explain the connection between teenagers' more-frequent snacking and a lower risk of excess pounds, Keast told Reuters Health.
The findings do not prove that snacking itself helps kids control their weight. A key limitation of the study, Keast pointed out, is that teenagers were surveyed at one point in time; all were part of a government health and nutrition survey conducted between 1999 and 2004, in which they were asked to recall everything they had eaten in the past 24 hours.
To help confirm a connection between snacking and lower weight, Keast said that studies should follow kids over time — seeing whether those who report frequent snacks are less likely to become overweight in the future.
For now, the bottom line for parents is to encourage their kids to have healthy snacks, according to Keast. That means foods like fresh fruits and vegetables, dried fruits, whole grains and low-fat dairy — the types of foods, Keast said, "that we know kids are not getting enough of."
Cutting out sugary beverages is another wise move. Keast noted that she and her colleagues did not consider sugar-sweetened drinks to be "snacks" in this study; but other studies have, and that may be one reason her team's findings differ from those of some past research.