Sugar, chemically glucose, is a fuel used by all our cells to quickly produce energy. It is burned in the presence of oxygen in tiny cellular boilers, mitochondria, releasing water, carbon dioxide and energy. Of course, cells can also consume fatty acids from food fats, a second energy source. At the level of the human body, it is about 300 to 500 grams of glucose which are thus consumed each day, a variable quantity according to our energy expenditure. The liver and muscles store enough sugar in the form of glycogen, a polymer uniting thousands of glucose molecules, to serve as a reserve.
Glucose is the favorite brain fuel which alone consumes 20% of all bodily needs, or about 4 grams per hour. Moreover, any hypoglycemia characterized by a drop in the level of blood glucose below 0.50 grams per liter (g/l) can lead to a coma, that is to say a stop of the functioning of the neurons, while the normal rate is 1 g/l.
Liver, brain and muscles, consumers and sugar managers
The liver is the glucose banker. It contains a reserve of around 80 grams, which it distributes to the organs for their permanent energy need such as the brain, the kidneys and the heart. The muscles are selfish and have their own reserve, which they use if necessary energy needed.
This muscle reserve of around 150 to 250 grams of glucose available is useful during physical exercise. In the absence of physical activity, the surplus of glucose provided by the diet associated with reserves full of glycogen is transformed into fat stored in adipose tissue!
This symphony associating the absorption of sugar, maintaining its concentration in the blood and the management of reserves is regulated by two essential pancreatic hormones: insulin and glucagon.
Sugar intake in the food
Nutritionally, 50% of the average daily energy supply, or 1,250 kilocalories in an moderately active adult, must be brought by sugar. But beware, it is preferable that this intake will be provided by slow sugars, the starch contained in bread, pasta or rice. For example, a plate of pasta brings about 80 grams of glucose in the form of starch.
Thus, the fairly slow digestion of starch avoids jerks of blood sugar that tire the pancreas. For an average daily energy consumption of 2,500 kilocalories, a sugar intake of approximately 350 grams will be necessary, 90% of which in the form of slow sugars and 10% (or 35 grams) per day in the form of fast sugars-that is to say free glucose present in the fruit juices, sodas or various desserts (the World Health Organization recommends not to exceed 50 grams per day).
The risk of overweight linked to too high consumption of fast sugars is often linked to excess food intake. Thus, a soda can contains up to 35 grams, a glass of orange juice 15 grams, a 10 gram sweet yogurt and many prepared dishes display more than 5 grams of glucose per portion of 100 grams.
Why don’t some people don’t like sugar?
An attraction to sweet foods, candies, cakes or various desserts depends mainly on education and the habits taken during childhood. Everyone has taste receptors in their taste buds, these tiny sweet taste detectors. Some people have a genetic variant of the TAS2R38 receptor, giving them a higher number of receivers. These people will tend to like sugar less and will be disgusted faster in case of excess.
Most sweeteners or false sugars such as aspartame and aceulfame are also perceived by bitter taste receptors. And this, in a variable way according to individuals, hence sometimes the temptation to return to the natural sweet taste of glucose or fructose contained in the fruits.
Can we talk about sugar addiction?
The attraction for sweet taste is innate in humans, probably because glucose is an essential fuel for our cells. The perception of taste translates into information provided to the brain. This information is perceived by the pleasure circuit and bring a pleasant feeling. Others are sent to the hypothalamus which takes advantage of it to regulate appetite by reducing at certain times of the day the response capacity of the receptors to the sweet taste.
Curiously, there are sweet taste receptors in the intestine, pancreas and even the brain. But how does sugar give us pleasure? He activates two regions of the brain, the insula then the tonsils, which make us feel pleasure. To achieve this, the brain stimulates the release of a key hormone of envy, dopamine. This key stimulates the circuit of pleasure and the insula is activated.
Why can the glucose or sucrose contained in certain drinks or pastries be addictive? Simply because the pleasure triggered by sugar in the brain is identical to the effect provided by a drug and causes addiction.
During evolution, the human species did not have many opportunities to protect itself from an excess of fast sugars, sinceHomo sapiens Furgivore and omnivorous, from the Paleolithic, consumed less than 30 grams of fast sugars per day. At this dose, there is no addictive effect.
The brain deceived by sweeteners
The role of sweeteners is to replace the glucose of food with false sugar which activates the receptors of sweet taste. Indeed, it works: the brain perceives a sweet taste and it calms the appetite for several minutes without bringing calories. Yes, but the receptors present in the intestine prevent the brain that a delivery of glucose is provided by informing the organs. Very quickly, the cells find that glucose does not arrive, which then triggers a renewed of a desire for sugar.
Fortunately, this effect only occurs during the frequent and repeated taking of sweeteners during the day, often observed with the abusive consumption of sodas containing false sugar. The solution to avoid these addiction phenomena is to decondition the brain to excess sugar and to get used to consuming fewer drinks and sweet foods, not too often during the day and to limit the contribution of fast sugars to less than 50 grams per day.
Sugar is an essential energy fuel. It is preferable to consume it in the form of a suitable contribution in slow sugars, thus limiting the risk of diabetes. Food must be balanced and associated with sufficient physical activity to ensure suitable energy expenditure, limiting the risk of obesity by transformation of excess food glucose in the form of fat.
