Is your 'healthy' snack really that good for you?

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Fifty years ago the term "snack" translated into an occasional piece of fruit, or a biscuit with a cup of tea when visiting friends. Muesli bars, rice crackers and protein balls were non-existent, as was loading up with extra food in our lunchbox to munch on throughout the day. Fast forward to the '80s and '90s and suddenly snacking became the norm, both to maintain energy levels and to distribute kilojoules throughout the day to optimise the metabolism. So what is the current view? When should we be snacking, what should we be snacking on and where do many of us go wrong in the snack food aisle?

It is fair to say that in general people snack far more than they need to, and generally consume far more kilojoules in their snacks than the body requires. From a physiological perspective, a well-balanced meal will fuel the body for four to five hours. For those who enjoy their first meal early in the day, or do not consume dinner until later in the evening, mid-morning and mid-afternoon are reasonable times for a fuel top-up – assuming the snack of choice is small (just 400-800 kilojoules).

This is where things go wrong with our snacking habits. Often we are not eating until 8am or 9am each morning, which means we do not need to eat again until lunchtime. Secondly, popular snacks such as muffins, smoothies, juices, milky coffees and snack bars can clock in at 1200 to 1600 kilojoules a serve. In these cases we can find ourselves eating too much, too often.

Research published in the International Journal of Behavioural Nutrition and Physical Activity conducted with more than 5000 Australian adults has confirmed that a "grazing" style of eating is associated with higher snack frequency, higher energy intake from snacks and eating later in the day.

Dr Rebecca Leech, head researcher from Deakin's Institute for Physical Activity and Nutrition, says there appears to be a link between snacking behavioural patterns and weight gain.

"This research helps to dispel the commonly held belief that eating more frequently is a useful weight-loss strategy," Dr Leech says. "Research has consistently shown that eating more frequently is linked to higher total energy intake overall, and increasing the number of eating opportunities may make it more challenging to stay within our daily energy requirements."

It appears that eating unnecessary snacks, even a milky coffee or a handful of crackers, plays havoc with the body's hunger and fullness signals. Studies in rats have shown that frequent feeding on sweet, carbohydrate-based foods stimulates dopamine sensors in the brain. This further fuels the desire to eat, even when we are not hungry, contributing to excessive kilojoule consumption and weight gain over time.

This does not mean that snacks should be banned completely. Rather, a snack needs to be thought of as a mini-meal. We only need to snack when we are genuinely hungry, and need to be kept full and satisfied for a further two to three hours until the next meal. This means that most of us will need a snack to keep us satisfied mid-afternoon, but morning tea may be needed only by those who exercise in the morning or eat a meal at 6 or 7am, so will begenuinely hungry again at 9am or 10am. If you are a little peckish at 11am, you are better waiting to eat until lunchtime, or eat lunch earlier, than you are to add in an extra "snack".

A well-balanced snack will contain 400-500 kilojoules, at least 5-10g of protein and/or fibre for fullness and blood glucose control, and 20-30g of good-quality carbohydrates to fuel the muscles and the brain. Stick to eating a protein-rich snack along with a carbohydrate. Options that fit this criteria include a small milk coffee, cheese and crackers, fruit and nuts, or Greek yoghurt with fruit.

The issue for many of us is that we opt for something sweet, but high-carbohydrate. Options that taste good – such as muffins, crackers, bars and bites – rarely contain the protein and fibre that will keep us full and satisfied for a couple more hours. For example, a muesli bar or a few rice crackers offers 20-30g of carbohydrates with just 2-3g of protein. These are the snacks that are easy to munch on but are ticking very few nutritional boxes. They also do not tend to keep us full, which means we can be tempted by more snacks just an hour or two later. Ideally a snack food will contain at least 5-10g of protein to help keep us full and satisfied along with 20-30g of good quality, wholegrain carbohydrates for energy.

One of the biggest issues with snack foods is that they also tend to be purchased away from the home, at convenience stores, cafes or local shops. Take a standard cafe order: a single milk coffee along with a muffin or friand will clock in at 2500 to 3300 kilojoules – that's kilojoules than a meal.

A simple way to take control of your snacking behaviour is to firstly consider if you really need to snack between meals. If you are not really hungry and could wait until your next meal, you will be better to do so. Next, make sure your snack choice will keep you full and satisfied for at least two to three hours.

Finally, if you know you are a mindless muncher and like to snack not because you are hungry but rather are a little bored, keep a ready supply of low-kilojoule, nutrient-rich options handy. Berries, cut vegetables, popcorn and herbal tea can all be consumed as "free snacks" (foods with minimal but that still offer some positive nutritional properties) and will help keep your overall kilojoule intake under control.

Susie Burrell is a nutritionist and dietitian.