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Research Review: Snacking

As a dietitian, I really value good research. We all eat, thus we all fancy ourselves experts at eating. Everyone has an opinion. Could it really be all relative, as the media may have you believe? As part of my blog, I want to bring you in-depth look at some recent research (i.e. more than the media soundbite), and help you understand how it may impact you. I hope you enjoy!


Credit: Elliott Brown

Since the late 1980s, the prevalence of snacking has increased significantly. One study showed that 71% of adults snacked in 1989-1994 while 97% of adults snacked between 1994-2006. In that same time, the percent of total calories that were consumed as snacks increased from 18 to 24% (1). Snacking is a big business, and shows no signs of slowing down.

People have different philosophies on snacking. Some think that it’s a way to curb appetite and prevent you from overeating, while keeping your metabolism going. But others lead with the idea that every time you eat is a chance to overeat. Which one is right?

Unfortunately, research has been inconsistent. Which leaves us in a bit of a lurch. Or just room for more research. Instead of trying to answer a black and white question of is snacking good for you, researchers are taking a deeper look into the grey areas. How do the content of the snack (both quality and quantity of food), the frequency of snacking, and the time of day of the snack impact whether snacking is considered a good thing.

A recent study (2) looked at snacking behavior and the associations with diet quality and body mass index (BMI). Specifically, the snacking behaviors they looked at included frequency of snacking, energy intake from snacks and percent of snack energy from different foods. It's this recent study that I want to dig into with you.

How’d they do it?

The data from this study came from a previously published study on a worksite nutrition intervention. Basically, instead of evaluating the intervention, this study evaluated the baseline data. It's a point-in-time look and evaluation of snacking behavior.

Researchers used a method called a 24-hour dietary recall with participants. Of course, there is some inherent error in this process. For instance, can you remember exactly what time you ate dinner last night, and how much of every ingredient you had? But it’s the gold standard used in research when it comes to self-reported eating, and skilled researchers can dig a lot of good information out of participants this way.

Once they had the information, researchers evaluated how close the participants diets aligned with the 2010 Dietary Guidelines for Americans. At the end of the process, a Healthy Eating Index (HEI) score is given, between 0 and 100, which tells you how close to the “ideal” participants are eating.

For this study, snacking was defined as “any eating occurrence not designated by the participant as breakfast, brunch, lunch, dinner, beverage only, or other meal.” Thus, in this definition, whether or not something is considered a snack depends on how the participant perceived it.

The researchers measured weight and height, to calculate BMI. In addition, they had access to demographic information (self-reported), physical activity (measured), and total daily energy intake (calculated).

What did they find?!

First, let’s talk about who the participants were. The average age was 43 years old. The participants were mostly female (67.4%), non-Hispanic white (65.7%), were educated (85% had at least some college), and had a BMI that classified them as overweight or obese (74%). Is this the average American? Not exactly. But it’s a decent sample to help us understand what’s going on, on some level. (Also, if I had to guess, this demographic isn’t that far off from the average health, nutrition or lifestyle blog reader.)

Now, let’s look at how they ate. Participants ate an average of 2,012 kcal/day, with an average HEI score of 58.2. The average participant snacked 2 times per day, but almost 85% of participants reported at least one snack per day. Snacks were consumed most in the early or late afternoon, and were more likely to be desserts/sweets or chips/crackers/popcorn. On average, participants ate 400 calories from snacks each day.

When the data was analyzed with statistical software, the researchers found no significant associations among calories from the snack, frequency of snacking, or time of day of the snack. Additionally, none of those outcomes were associated with diet quality or BMI.

But, the type of food consumed when they snacked was associated with diet quality and BMI. When snack calories came from either fruit/fruit juices or nuts, the participants had a higher HEI score. On the other end of the spectrum, when snack calories came from desserts/sweets and sugar-sweetened beverages, the participants had a lower HEI score. Snack calories coming from vegetables was associated with a lower BMI, and snack calories from desserts/sweets was associated with a higher BMI.

What does this mean?

Choices matter.

Specifically, choosing fruits, vegetables and nuts as a snack sets you up for success, while choosing sugar-laden treats does not.

Of course, for snacking to be part of a successful weight loss (or weight maintenance) initiative, you need to balance overall calories throughout the day. Meaning that if you eat more calories as snacks, the calories you get at meals must be lower. As a Katie Goldberg bonus tip, I’d recommend keeping your breakfast robust, and trimming calories elsewhere.

Since this study was an observational cross-sectional study, we can’t draw any firm conclusions about causality of snacking and BMI or diet quality. However, this study does support the hypotheses that snacking is not necessarily an unhealthful behavior, and that good snack choices can contribute to a healthful diet.

When you reach for a snack, I recommend a fruit or veggie and a source of protein. For example:

Source: Frank Mari

Source: Frank Mari

  • Apple + cheddar
  • Pear + almonds
  • Mango + cottage cheese
  • Orange + pistachios
  • Bell pepper + hummus
  • Tomato + hard boiled egg
  • Cucumber + jerky
  • Carrots or celery + nut butter

How has snacking been beneficial – or detrimental – to your health goals? Tell me in the comments below!


References:

  1. Pienas C, Popkin BM. Snacking increased among US adults between 1977 and 2006. J Nutr. 2010;140(2):325-332.
  2. Barnes TL, French SA, Harnack LJ, Mitchell NR, Wolfson J. Snacking behaviors, diet quality, and body mass index in a community sample of working adults. J Acad Nutr Diet. 2015;115(7):1117-1123.