So we often hear that we should avoid sugar wherever possible… which is fine, because we know that adding sugar to our diet results in extra calories right? And those extra calories can lead to weight gain and a host of other problems over time such as diabetes, high blood pressure, arterial disease and more… but why is sugar so bad? What is it that makes it so damaging to our body? Is it simply the volume we are consuming? or is it something else?
Sugar (table sugar) is better known as Sucrose, it is a disaccharide, which means it is made from two single sugars (monosaccharides), these two single sugars are Glucose and Fructose.
Glucose is used by almost every cell in our body, this includes brain cells, nerve cells, kidney cells and of course muscle cells, it is used to make energy. Glucose can also be stored in the muscles and in the liver quite easily. Your body needs glucose, it uses glucose and it stores glucose with the aid of insulin as glycogen or fat.. we are not saying too much glucose won't cause problems, but generally speaking your body knows how to deal with it.
Fructose however is a different story. Fructose is broken down very differently in the body to glucose, it must be broken down predominantly by the liver. The pathway fructose takes in the liver is not unlike Ethanol, (Alcohol).. the main difference being it does not acutely affect the central nervous system (you don’t get drunk). Fructose stresses and disrupts the liver mitochondria (which make energy), and also a process called ‘De novo lipogenesis’, which is essential in converting carbohydrates into fats. Fructose does not produce an insulin response but can lead to insulin resistance and metabolic disease over time. Fructose also promotes free radicals which leads to cellular damage and premature ageing, it has also been shown to affect the brain and its ‘reward system’ which can lead to excessive sugar consumption. Finally, fructose consumption has increased worldwide, paralleling the obesity and chronic metabolic disease pandemic.
Ok so Fructose is a bad guy, but if its so bad why do we find it in our fruits and vegetables? The simple answer is that our body can deal with small amounts of fructose pretty well, and nature adds another component to our fruits and vegetables which reduces the amount fructose we absorb.. this component is Fibre … which is worth a whole other blog on its own.
To sum up, a calorie from fructose is very different to a calorie from glucose or other sources. Fructose promotes excessive fat storage, high blood pressure, metabolic disease (diabetes), liver disease (fatty liver) and a condition known as metabolic syndrome.
What to do: Avoid added sugar where possible, because table sugar is 50% fructose. Restrict sugary drinks, fizzy drinks and even fruit drinks – they have no fibre. Reduce processed foods and increase whole foods and raw foods. Eat more fibre - from real fruit and eat plenty of vegetables and salads. Maybe plan your meals a little more to make it that bit easier. Identify where you might be going wrong, be honest, don’t try to change too much in one go .. but start by changing something.
Pure White and Deadly - John Yudkin
Fat Chance - Robert Lustig
Thanks for reading..
More next time, or see the blog on www.understandingnutrition.co.uk