Ever read a diet book? Then you've heard the advice to snack on small amounts of protein in order to end hunger pangs and to prevent you from overeating at dinner time. A new study explores how high protein afternoon snacks work out for teens. Not only did high protein soy snacks help the teens control their appetites, the University of Missouri researchers say, the snacks also positively influenced their moods and cognitive abilities.

It’s nearly summertime, so most everyone is thinking about how they will look in skimpy clothes, shorts, and a bathing suit. Dieting, then, is on many minds, including those of teens. Key to any good diet is the all-important afternoon snack. What snacks work best at keeping hunger at bay?

For the study, 31 healthy 17-year-olds, give or take a year, rotated through three afternoon snacking routines (in randomized order). For three days, they ate a high protein soy snack; for another three-day period, they ate a high fat snack; and for a third three-day period they ate no snack during the afternoon. Interestingly, both snacks, whether high protein or high fat, appeared as identical chocolate-peanut-caramel–flavored pudding.

On day four, following each of these three routines, the participants completed an eight-hour testing day, which contained pre- and post-snack questionnaires, MRI brain scans, mood tests, and cognitive exams. On each day, the teens were provided with dinner and evening snacks that they could eat as they pleased. Meanwhile, the wily researchers watched and documented what and how much participants ate on each day.

The Winning Snack

How did the teens fare? Compared to not snacking at all, eating any snack reduced participants' appetites, though the high protein snack did a better job of that than the high fat snack.

And, compared to days when they didn’t snack at all, the teens ate more protein at dinnertime when they’d snacked on protein during the afternoon. On their high protein days, they also ate more protein and less fat at supper compared to their high fat snack days. Plus, the high protein snacks appeared to reduce their confusion and increase their cognitive flexibility on test day. As a result of these findings, the researchers suggest teens eat high protein afternoon snacks daily, making sure to choose soy foods in particular.

“Standard meals tend to go to the wayside for kids this age — particularly from mid-afternoon to late evening — and many of the convenient ‘grab-and-go’ snacks are high in fat and sugar," Dr. Heather Leidy, an assistant professor of nutrition, stated in a press release. "When kids eat high-protein snacks in the afternoon, they are less likely to eat unhealthy snacks later in the day, which is particularly important for kids who want to prevent unhealthy weight gain.”

Source: Leidy HJ, Todd CB, Zino AZ, et al. Consuming High-Protein Soy Snacks Affects Appetite Control, Satiety, and Diet Quality in Young People and Influences Select Aspects of Mood and Cognition. Journal of Nutrition. 2015.