When it comes to sugar, the role it plays and what’s healthy, there is great confusion among consumers. Fortunately science, human physiology and the molecular structure of whole natural foods versus processed foods makes this an easy topic to explain. For ease of digesting, I have broken my explanation down by addressing some basic nutrition/physiology & common questions that I am often asked and then some take home tips at the bottom for healthy sugar consumption.
Sugars are a form of carbohydrates known as simple carbohydrates for their short molecular structure and rapid rate of absorption into the blood. The main sugar, glucose, is used for energy production throughout the body and is the primary fuel that our brain runs on. In fact, the brain uses approximately 120g of glucose per day when the body is at resting state (over 400 calories a day burned as fuel for the brain) (1).
Glucose is also stored within muscle and the liver as glycogen (many glucose molecules joined together) as ‘energy reservoirs’ so the body has an even supply of glucose it can supply the brain, muscles, blood and other areas of the body for important physiological reactions (Glycolysis) which produce energy compounds known as ATP.
So wait, sugar is a necessary fuel that our body needs for optimal brain and energy production? Yes, despite ‘sugar’ being slammed in the media and coined the bad guy through Chinese Whispers, it is a very important molecule for the health of the human body. It is the form and source of sugar which needs to be distinguished in order to understand what ‘sugars’ are good for us and what ‘sugars’ should be minimised. Read on and I will take you through this logically.
Sugars can occur naturally (whole food sugars) in their natural state or can be refined and then added to processed or semi processed foods to create added sweetness. When the food industry realised that they could create refined sugars and essentially artificially make foods sweeter than natural state foods, they took advantage of this to create greater customer appeal and more sales and so the battle between nature and manufactured foods began. A battle that we are still faced with today.
The Keto Diet is not the topic of this blog, but when sugar is covered it’s worth covering, so let’s think about this logically. For the body to go from using glucose as fuel to ketones you have to starve it of carbohydrates.
Brain. Glucose is virtually the sole fuel for the human brain, except during prolonged starvation.(1)
Even in starvation, where the liver provides ketones as an emergency fuel source, the body will STILL find ways to use glucose where it can.
I find it interesting that anyone would want to starve the body of it’s primary fuel in order to then deliver the brain with what is clearly a ‘second preference’ fuel source. That’s like putting the standard unleaded fuel in your new high performance car vs the premium fuel. You wouldn’t do that unless you absolutely had to right? And that is why the body can use ketones…it’s a back up, a physiological adaption so to speak, to allow the body to still survive when starved of carbohydrates. When there is no other choice. Note I said ketones allow the body ‘to survive’ not the ‘thrive’.
The very fact that being in ketosis long term is NOT normal or healthy can be backed up by the lack of science showing any population to thrive on such a diet long term. Keto proponents will no doubt bring up the Inuit population, however that is merely clutching at straws as these people ate fish, whales & seals were not on chronic ketosis and had a genetic mutation which prevented them over producing ketones (2). Sadly, the Keto diet, which mind you has been shown to perhaps be effective for very specific clinical conditions such as childhood epilepsy, has become a mainstream diet which products, cafes and ‘influencers’ are profiting from at the detriment to your long term health.
Unrefined carbs, which contain the complete plant (fibre and all the phytonutrients), are consistently associated with a decrease in chronic disease risk. Despite ‘anti-carb experts’ thinking carbohydrates cause obesity, we know that unrefined carbohydrates that are eaten in as close to their whole natural form as possible are health promoting & are not to be blamed for weight gain. When you juice a plant, the % of sugar consumed actually increases because in the juicing process you lose most of the fibre & also some phytonutrients (grams of sugar stays same but as a % of total volume it’s greater). Is a fresh juice going to kill you? No, & with health being a spectrum its far healthier than drinking a long shelf life, heavily processed juice from the local 7-11. But, if you have the choice of a daily smoothie bowl with whole fruits versus a juice, and both fit in your calories, I’d be choosing the smoothie bowl. Weight gain will occur when you are in a calorie surplus, not from consuming sugars alone. Generally, by sticking to whole plant food sources of sugar, rather than refined processed sources, you will consume less calories and thus will have greater chance of maintaining or losing weight.
As humans, we have been eating natural sugars from the early days. In the wild, sugar provided a way to identify safe plants versus a warning flag for potentially poisonous plants. Sugars in plants offer the body a source of glucose which is the primary fuel our body uses for energy. Over time, because of this affinity for sugar, humans worked out how to extract sugars & add them to processed foods. This process allows you to consume way more sugar than you could if you were eating naturally occurring sugars in their whole plant form because they are more concentrated & provide less satiety. In the USA, the average person consumes 30 teaspoons of sugar a day across their meals. Sugar itself is not ‘harmful’ – it’s a molecule our body is able to use for energy very well, however the issue is excessive consumption of refined sweeteners & the resultant calorie surplus/weight gain which is linked to a whole lot of poor health outcomes including T2 diabetes, cancer, decreased immunity, etc.
Firstly, its good to be able to visualise how many tsps of sugar are in certain foods you consume. The best way to do this is by knowing that 4g of sugar = roughly 1 tsp. So, if you have 5 Tim Tams (8g sugar per Tim Tam), you are consuming approx. 10 tsps of sugar. The American Heart Association recommends no more than 6 tsps (24g) of sugar for women & 9 tsps (36g) for men per day. Obviously, with higher activity levels this can go up. This recommendation is more than likely a way of helping people avoid over consumption of processed foods & calories that lack micronutrients.
Non-Nutritive Sweeteners (NNS) provide fewer calories than sugars and are far sweeter (often 1,000’s of times sweeter). Examples of common NNS are Aspartame, Stevia, Saccharine and Sucralose. Whilst there has been some clinical studies suggesting they may help with weight loss or chronic disease, the evidence is not very compelling (3,4).
There is a lack of properly designed randomized controlled studies to assess their efficacy in different populations, whereas observational studies often remain confounded due to reverse causality and often yield opposite findings. Pregnant and lactating women, children, diabetics, migraine, and epilepsy patients represent the susceptible population to the adverse effects of NNS-containing products and should use these products with utmost caution (3).
Regarding weight loss, if we think about this logically, if you substituted refined sugars for sweetener you would be consuming less calories and thus have a lower calorie intake over the day. However, it’s not that simple. If you are consuming foods that are artificially sweetened, and often even sweeter than products with standard sugars, you are likely to eat more of them. You are also doing yourself an incredible disservice when it comes to enjoying the natural sugars in fruits which simply cannot compete with the sweetness of non-nutritive sweetness. Perhaps this tricking of the brain, and lure to over consume, is why today we are seeing such a rise in Type 2 diabetes and obesity in children (5)
Data from large, epidemiologic studies support the existence of an association between artificially-sweetened beverage consumption and weight gain in children…
…dissociation of the sensation of sweet taste from caloric intake may promote appetite, leading to greater food consumption and weight gain. In addition, increased consumption of added caloric sweeteners has been associated with lower diet quality in children, perhaps by altering taste preferences toward sweetened foods in place of more healthful foods, such as fruits and vegetables; this mechanism could apply to artificial sweeteners as well (4).
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