ZOE snacking study: What should you do?

You might have heard that snacking is bad for you, but is that really true? 

Because there’s been little research into snacking’s impact on health, ZOE’s scientists decided to investigate. 

But understanding the links between snacking and health isn’t as straightforward as you might think — there’s a lot to consider: 

• when you snack

• what you snack on

• how many times a day you snack 

• how much energy you get from your snacks

Below, we’ll explain what we did, what we found, and what it means for you. 

Spoiler alert: Snacking isn’t necessarily bad, but there are some key factors to keep in mind.

What did we do?

We used data from 854 participants aged 18–65 who had enrolled in ZOE’s PREDICT 1 study. 

Each participant provided detailed information about what they ate and when. They also logged their hunger levels. 

These measures are important. After eating, it’s normal for fat and sugar to enter your blood. But if sugar or fat stays in your blood for too long, it can be bad for your health in the long run. 

What did we find?

Our analysis showed that 95% of people ate at least one snack every day. And, on average, snacks accounted for almost one-quarter of participants’ daily calories.

Frequency, quantity, and health

We searched for links between how frequently people snacked, how many calories they got from snacks (we called this “quantity”), and their health. 

Perhaps surprisingly, we didn’t find any links. 

In other words, the frequency and quantity of your snacks don’t seem to harm your health.

So, what aspects of snacking do influence your health?

Quality matters

Low-quality snacks include cakes, candy, and cookies, while high-quality snacks include nuts, seeds, and fruit.

And unlike frequency and quantity, quality does make a difference to your health. 

Insulin resistance means your body doesn’t respond as well to insulin. So, it’s harder to move sugar away from your blood to be used as energy.

People who ate poor-quality snacks also reported feeling more hungry than those who ate good-quality snacks.

Ultra-processed snacks

Participants who mostly ate unprocessed and minimally processed snacks did better on some health measures, compared with people who mostly ate ultra-processed snacks.

For instance, they had lower body weight, less belly fat, lower levels of fat and sugar in their blood, and better blood fat responses to food.

Snack quality wasn’t the only factor to influence health, though.

What about timing?

We found that people like to snack at different times:

• 13% ate most of their snacks in the morning (before midday)

• 39% ate most of their snacks in the afternoon (between midday and 6 p.m.)

• 31% ate most of their snacks in the evening (after 6 p.m.)

• 17% were grazers — they ate snacks randomly throughout the day

These differences seem important for your health.

People who snack in the morning tend to eat higher-quality snacks and take on fewer calories from their snacks than those who snack at other times.

Similarly, late-evening snackers with low-quality snacks had poorer health measures than late-evening snackers with good-quality snacks.

So, if you snack later in the evening, choosing higher-quality snacks may reduce the unfavorable effects.

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What should you do?

Despite what you might have heard, snacking isn’t necessarily bad for you — the important factors are quality and timing.

If you tend to snack later in the evening, try to move your snack schedule earlier in the day.

Kate Bermingham, Ph.D., is ZOE’s senior nutrition science manager, a researcher at King’s College London, and lead author of the study on snacking. 

We asked Kate for her advice. She said, “Many of us rely on snacking because life is busy and we’re on the go. So, when you’re choosing a snack, opt for something high-quality, like fruit or nuts and seeds.”

A mismatch

We also asked Kate which of the study’s findings surprised her the most.

“It surprised me that many people are discordant for snacking and main meal behavior. In other words, some people have high-quality meals but poor snack quality, or vice versa.”

For instance, more than 1 in 4 people consumed high-quality main meals but low-quality snacks. 

And if you’d like to learn more, we have a podcast on snacking featuring our scientific co-founder, Prof. Tim Spector, and our chief scientist, Dr. Sarah Berry.