How to snack healthy: Timing and quality over frequency, study flags

20 Sep 2023 --- UK researchers suggest that snacking may not be unhealthy as long as people consume high-quality snacks. In a new study, participants frequently eating high-quality snacks, such as nuts and fresh fruits, were more likely to have a healthy weight than people who don’t snack or consume unhealthy foods. 

Furthermore, snacking frequency and energy intake were not associated with cardiometabolic risk markers, while snack quality can lead to better metabolic health and decreased hunger. 

Most of the study participants (95%) were snackers, consuming at least one daily snack. On average, people consumed 2.28 snacks daily and obtained 24% of their daily energy intake from snacks. 

“We are excited about this research as we believe it will help to dispel the idea that snacking is unhealthy and steer the focus more toward the quality and timing of our snacks,” first author Kate Bermingham, senior scientist at ZOE and postdoctoral researcher at King’s College London, tells Nutrition Insight. 

“Our analysis shows high-quality snacks can improve metabolic health and hunger levels. Therefore, snacking is not bad for you as long as the food quality is good and you are not eating late into the night.” 

She adds that the study contributes to the growing literature highlighting the importance of food quality and timing as driving factors behind improved health outcomes. 

A quarter of the study’s participants (26%) reported combining healthy meals with poor-quality snacks, such as highly processed food and sugary treats. Moreover, people snacking after 9 PM tended to eat energy-dense foods high in fat and sugar. 

High-quality snacks include whole fresh fruit and vegetables, nuts and seeds, typically high in fiber.Study outcomes 
Lower snack quality was associated with increased body mass index (BMI) and higher blood markers, including elevated fasting and postprandial triglycerides – fat that circulates in the body – fasting insulin, insulin resistance and hunger. These blood markers are associated with metabolic diseases such as stroke, cardiovascular disease and obesity. 

Moreover, late-evening snacking was associated with poorer blood markers than all other snacking times, which the researchers suggest indicates that late snacking reduces the overnight fasting interval. Morning snackers had a higher snack quality and lower energy intake than people consuming snacks later in the day. 

Compared to main meals, snacks were, on average, higher in carbohydrates, fat and sugar while lower in protein. 

The most popular snacks were drinks, candy, cookies, nuts and seeds, fruit, crisps, bread, cheese and butter, cakes and pies and granola or cereal bars. 

The most significant contribution to calorie intake were cakes and pies (14%), breakfast cereals (13%), ice cream and frozen dairy desserts (12%), donuts and pastries (12%), candy (11%), cookies and brownies (11%), nuts and seeds (11%) and corn snacks, such as chips (11%).

Healthy snacking strategies 
The researchers explain that high-quality snacks include whole fresh fruit and vegetables, nuts and seeds, typically high in fiber and other healthful food components. These mediate hunger and appetite, glycaemic control and other cardiometabolic risk factors. 

“Focusing on the quality of our snacks, we can make significant changes to our energy levels and mood throughout the day,” highlights Bermingham. “Opting for whole foods where possible ensures a nourishing option with a balanced mix of nutrients. For example, a bowl of yogurt with mixed berries and nuts is a great option.” 

Late-night snacking was associated with poorer blood markers and lower-quality snacks.“If you know you are likely to snack when on the go, try to have wholefood-based options prepared to avoid grabbing heavily processed, unhealthful foods.” 

Bermingham underscores that it is essential for consumers to be aware that food labels suggesting a product is a healthy option may be deceiving. For example, foods marketed with terms such as “low-fat,” “low-sugar” or “diet” are often ultra-processed and “it’s best to avoid them.” 

“Setting an eating cut-off time in the evening can be helpful to avoid late-night snacking. If you fancy something sweet in the evening, try to have it at the end of the meal rather than a late-night treat. This is a great strategy to improve your metabolic health regarding blood fat and blood sugar levels.”

Diet intervention study 
The study, published in the European Journal of Nutrition, uses high-resolution diet data from the ZOE PREDICT 1 cohort, a diet intervention study that studies diet-cardiometabolic interactions. Participants recorded all diet intakes on a specialized study app, self-reporting meal types. 

The 854 study participants visited the clinic for one day at baseline, followed by a 13-day at-home period. Snacks – foods or drinks consumed between main meals – were self-reported across two to four days. Data was weighted and checked by nutritionists in real-time.

The researchers assessed demography, diet, fasting and post-meal cardiometabolic blood and anthropometric markers – height, weight, BMI, visceral fat, waist-to-hip ratio – and stool metagenomics. 

They note that the study’s cross-sectional nature did not allow them to assess causality. Moreover, study participants may under-report eating frequency or under-report energy intake. 

The researchers urge that public health efforts focus on making whole foods more attractive and accessible.The study had limited data by only using two to four days of logged data, did not have information on work versus free days and could not examine the seasonality of snacking behaviors. Although snacking intake was similar to previous surveys, the current study participants differed from the average UK population. 

“Ideally, a randomized controlled trial would allow us to infer causality and provide direct evidence of the effect of snacking on health beyond associations,” highlights Bermingham. 

“A trial with a representative cohort including different sexes, ages and socio-economic backgrounds would allow us to understand generalizability to certain populations.” 

Upping public health efforts 
The researchers note that snacking behavior may be a key diet target to ameliorate risk factors for diet-related diseases while snacking earlier in the day can be part of a healthy lifestyle. 

However, they caution that the current food environment makes it difficult for consumers to change their snacking behavior, even if they have sufficient diet information, food knowledge and healthy eating intentions. 

“We are surrounded with convenience food options, meal deals featuring sugar-sweetened drinks and packaged snacks as the most affordable options,” explains Bermingham. “Public health efforts should focus on making whole foods more attractive and accessible, which will make it easier for us to choose high-quality snacks over highly processed options.”

“The targeted marketing, delicious moreish texture and flavors and convenience of [unhealthy snacks] make them especially attractive in our time poor society. The environment we live in makes it easier for us to grab a pre-packed, nutrient-poor snack that will not sustain our energy levels and leave us wanting more.”

By Jolanda van Hal