December is now in full swing and the Christmas period is looming. Many of us will have opened the first of our advent calendar windows to reveal a tempting morsel of chocolate (probably not the 85% cocoa, laced with heart-healthy polyphenol antioxidant type) and thus starts the build up to a week’s worth of over-indulgence (not counting the work Christmas do booked for this week to avoid the crowds closer to Christmas, or the pre Christmas get together pencilled in with Bob and Margaret this weekend). Over the next few weeks there will be the usual excuses of ‘just the one mince pie’, or ‘that small glass of sherry is okay’, because ‘after all, it is Christmas’. All in all we are destined for a carbohydrate and sugar-infested food overload that starts now and will most likely see us through into the New Year. Come January, the scales will groan and gym memberships will (briefly) flourish.
Sugar, it seems, is everywhere and in (almost) everything, with the problem first arising some years ago when we began to demonise fat. Removing fat seemed to be the answer (after all it was considered the ‘bad-boy’ of nutrition) but this only made our food taste pretty awful and so the food industry compensated by adding refined sugar. (What else was there?) The issue with this is that overconsumption of these refined sugars (like sucrose or fructose – naturally absent from the human diet) are now known (together with other factors) to contribute to drive the current obesity epidemic – the sugary stone that gathers no moss. Oh if only we knew then what we know now!!
It’s not uncommon for people to say they find sugary food addictive (my mouth is still watering from having mentioned mince pies earlier) and this is not an unreasonable association if we look at the chemical processes in the brain that come about through the overconsumption of sugar-dense, heavily refined and processed food and drink. Indeed, the ‘reward’ processes are almost those that arise when an individual is exposed to certain drugs. A classic example can be found in a 2007 study, when 94% of rats who were offered either highly sweetened water or cocaine took an unprecedented beeline for the sweetened water, an image that almost makes you drop your free sugar-loaded cake in surprise!  But what do we mean by ‘free sugars’? These are sugars that are added to a product by manufacturers, cooks or consumers, or the sugar that is naturally present in syrups, honey and fruit juices. It doesn’t include sugars in dairy products. According to the Scientific Advisory Committee on Nutrition (SACN) – on a daily basis, children aged 4 to 6 should have no more than 19g, children aged 7 to 10 no more than 24g and children aged 11 years and upwards, as well as adults, no more than 30g of these free sugars per day and yet one 330ml can of a certain popular brown, sweet fizzy drink contains as much as 35g sugar, a drink highly criticised for helping to fuel the sugar crisis. But even so-called ‘healthy’ products now have incredibly high sugar levels: a small bottle of VitaminWater (also owned by the maker of that brown drink) is loaded with added sugar, particularly fructose (a type of fruit sugar that overwhelms the liver and therefore comes with its own set of unique health issues). It’s worth pointing out at this time that one delicious all butter, melt-in-the-mouth mince pie contains 225 calories and 22g sugar. Depressing, isn’t it.
So what is it that is so wrong about sugar, don’t we need it for energy? Well yes, it is true that the body requires a relatively constant input of sugar (well, glucose actually; this is the sugar produced when we digest any carbohydrate), for normal functioning. When we consume a meal containing carbohydrate, blood glucose levels rise, triggering the production of the hormone insulin, which acts like a key, unlocking tiny ‘doors’ within our cell membranes, allowing the absorption of glucose into the cells resulting in a subsequent lowering of glucose levels in the blood. If our blood glucose falls below a certain level, the hormone glucagon acts to allow stored glucose (as glycogen) back into the bloodstream. Thus it is the combined action of these two hormones that keep blood glucose levels in a healthy range. Sporadic, high-free sugar-containing foods are the root cause of the ‘sugar crashes’ we feel as the direct result of an increase and subsequent decline of blood glucose in the body system after eating high-sugar foods. In addition, more often than not, more insulin than is actually needed is produced in response to the large, rapid ingestion of these sugary foods. Over time this can lead to insulin resistance, whereby the body produces insulin but does not use it effectively. When people have insulin resistance, glucose builds up in the blood instead of being absorbed by the cells, leading to type II diabetes. Currently, type II diabetes affects around two and half million people in the UK – and is on the increase.
Before you start panicking that all you’ll be able to eat this Christmas is turkey (or nut roast) let me be clear that not all carbohydrates cause a spike in blood glucose levels. We can break down carbohydrate into starches (also known as complex carbohydrates), sugars and fibre. Fibre is the indigestible part of plant foods, including fruits, vegetables, whole grains, nuts and legumes. Fibre is important for maintaining digestive health; it helps to keep us ‘regular’, as well as helping to make us feel full after eating. In addition, we can place carbohydrates into groups depending on how they affect our blood glucose levels and allocate them with a Glycaemic Index (GI) number. Complex carbohydrates have a low GI and release glucose slowly, while simple sugars (like white refined table sugar) need little if no digestion and are absorbed quickly, flooding the system and are therefore allocated a higher GI. The good news is we can happily tuck into our veggies with our turkey (or nut roast). Be mindful of how many roast potatoes to sneak onto your plate, however, as they contain carbohydrates that can rapidly increase your blood glucose levels. In contrast, non-starchy vegetables are the ones to aim for (such as kale, onions, asparagus, broccoli, cabbage, Brussels sprouts and so on) because they don’t cause a spike in blood sugar, go a long way in satisfying appetite and boost our intake of vitamins, minerals and fibre.
For most of us, totally excluding those Christmas treats that we love would make the seasonal period rather dull and we can be forgiven for indulging every once in a while! However, be aware that if you’re a pudding (cake, mince pie, sweet chocolate–get the drift?) kind of person then Christmas really will be your sugar enemy. So if you are out and about and cannot resist, then moderation is key: make sure you stick to (at the most) one mince pie or one slice of cake/pudding and remember to keep the serving size on the small side. Eating slowly can help slow down the speed at which sugar is absorbed. If you are at home, apply the rule out of sight, out of mind to help to avoid snacking between meals. It can be easy to leave highly temping foods out which can lead to ‘small’ indulgences that not only result in sugar spikes, but help load up with the excess calories that see us piling on those Christmas pounds. Alternatively you can make your own, giving you total control of the ingredients you put into your treats, and with ambassadors such as Jamie Oliver publishing recipes targeted at limiting sugar intake (you can find them on the web) it’s not so hard to have your cake and eat it!
- Lenoir M, Serre F, Cantin L, Ahmed SH: Intense sweetness surpasses cocaine reward. PloS one 2007, 2:e698.