What is the amount of sugar consumed by the average adult? 34.5 teaspoons daily! That is approximately 240 teaspoons of sugar weekly! Most of the time it is unknowingly ingested with high levels of sugar mainly in the array of processed foods and sweetened drinks that flood an average individuals diet.
Obesity is the collaboration between genetics and the environment and since genetics are difficult to control, the main focus of individual betterment should be placed on the environment. The Thermodynamic Law is used as the main tool in describing the manner with which weight is gained as the law defines how quantities behave under various circumstances in metabolisation.
A calorie is just a calorie – if you consume more calories than you burn; you gain weight and you lose weight if you burn more calories than you consume. However, this original view of weight gain has changed since recent research has highlighted that not all calories are metabolised the same way. Consequently, when understanding obesity, it is crucial to highlight that eating and burning calories are secondary to the biochemical process our body undertakes. Evidence for this can be seen in the existing epidemic of obese infants under 6 month olds, who do not consciously over-eat, but are instead fed the wrong types of food. Bringing about the notion of a calorie is not just a calorie, that they are not metabolised in the same way.
Research highlights that higher energy intake comes from the carbohydrates than from fat. This is evident from statistics that show that from 1960-2000, the percentage of fat intake has reduced from 40% to 30% yet obesity prevalence has increased from 15% to 30%. An example of this statistic is that sugar is the main carbohydrate in soft drinks. These drinks consist of High Fructose Corn Syrup (HFCS) which is a sweeter and cheaper substitute of sucrose. Sucrose and HFCS are both made up of glucose and fructose, with HFCS containing 42%-55% fructose and sucrose containing 50% fructose; thus both sugars are equally poisonous! Fructose is a fruit sugar it is considered somewhat healthy and safe, however the quantity that individuals consume is increasing the prevalence of metabolic diseases like obesity, hypertension, diabetes type 2, and more in society to date.
Unfortunately, also the consumption of fructose has increased dramatically since the early 1900s. The daily consumption in the 1930s of fructose started with 15g/day, doubling in the 1970s to 33g/day and 55g/day in the 1990s. In the 21st Century, an excessive 73g/day is consumed! This dramatic increase mainly resulted from the popularity of low-fat diets in the 1980s (since it was assumed that it was the excess fat intake that was resulting in obesity) which lead to society adopting a high carbohydrate diet. Since reducing fat levels in foods made the palatability of them decrease, manufacturers began to add large amounts of HCFS to uplift the taste. Consuming low-fat processed food meant replacing fat with carbohydrates, adding excess sugar to make it tasty.
A paediatric endocrinology Professor; Robert Lustig from the University of California, San Francisco, has explained that not all sugars are digested in the same way. Lustig emphasises that the extra fructose molecules in added sugar causes individuals to not feel sated (hence overeat), fails to be converted into energy, transforming into liver fat which builds insulin resistance leading to diseases such as diabetes, heart disease and obesity.
If a calorie was just a calorie, then we would expect them to all work in exactly the same way. Now if you consider the metabolisation of 120 calories of glucose; 80% would be used up by muscles, organs, and the body, whilst the remaining 20% will be sent down to liver (the organ that removes toxins from the body). When the 20% is sent to the liver, it is converted into Glucose 6-Phosphate which turns into Glycogen, the storage form of sugar. It is also converted into Pyruvate which leads to Citrate. This Citrate is then worked on by fat storing enzymes, converting it into VLDL (a type of bad cholesterol). The total of bad cholesterol that is generated from the 120 calories is only 0.5g (i.e 0.5g of fat).
The metabolisation of 120 calories of sucrose – 60 of those calories are glucose (20% go to the liver), and the other 60 calories are fructose; of which ALL go to the liver! Evidently, the total load going to the liver is 3 times more when digesting sucrose than when metabolising glucose alone. In the liver there are a series of processes taking place, where a lot of phosphates are being donated. From this process, there is a waste product called uric acid which has a fundamental role in the development of high blood pressure. Just like in the metabolisation of Glucose, Pyruvate is generated, however in a much larger quantity, leading to a large amount of citrate, thus VLDL and consequently the production of more fat!
This clearly highlights that when you ingest fructose you are in fact metabolising it as fat, even though it is a carbohydrate! These 120 calories of sucrose acts very differently in the body in comparison to glucose and other impacts include that fructose increases lipid droplets which lead to a fatty liver. Also, it generates free fatty acids which travel to your muscles and make you muscularly insulin resistant, increasing insulin levels and the production of fat. This results in an excessive amount of insulin, making the brain confused and not being able to recognise leptin signals; hence causing over-eating.
When an individual ingests fructose it changes the way their brain recognises energy from the catalyst of leptin, failing to give the correct feedback to the brain from the increase in insulin resistance. Since the addition of HFCS has become increasingly popular, becoming label wise, re-introducing fibre, taking part in continual physical activity, and reducing sugar intake is a crucial route to tackle in the fight against metabolic diseases.
Lustig, R. (2012) Fat Chance: The Bitter Truth About Sugar, HarperCollins Publishers, United Kingdom