Let's start with the chemical composition of sugar. Refined sucrose is commonly referred to as table sugar or just sugar. It plays a central role as a leading processed food additive and is consumed all over the World. The average person in the U.S.A. consumes over 22 teaspoons of added sugar per day.
The stuff we know as table sugar or sucrose is a molecule composed of 12 atoms of carbon, 22 atoms of hydrogen, and 11 atoms of oxygen (C12H22O11). Sucrose is actually two simpler sugars stuck together: fructose and glucose. *Fructose is the most harmful component of these two. In recipes, a little bit of acid (for example, some lemon juice or cream of tartar) will cause sucrose to break down into these two components.
Modern industrial sugar involves processing in factories and typically involves bleaching and crystallization, producing a white, odorless, crystalline powder with a sweet taste of pure sucrose, devoid of vitamins and minerals.
About 175 million metric tons of sucrose sugar were produced worldwide in 2013.
Like all compounds made from these three elements, sugar is a carbohydrate. It’s found naturally in most plants, but most often in sugarcane and sugar beets—hence their names.
Another industrial sugar that is prevalent in our food supply is fructose. High fructose corn syrup (HFCS) is a sweetener made from corn starch that has been processed by glucose isomerase to convert some of its glucose into fructose.
And what about the so-called "natural" sugars, like honey, organic evaporated cane juice, or syrups from agave, brown rice or maple? The chemical composition does vary slightly, but these sugars aren't really healthier for you, especially when your total sugar consumption is high.
How much added sugar is too much?
Currently, the U.S. government does not require food manufacturers to quantify added sugar on food and beverage labels - only total sugar. The USDA Dietary Guidelines Advisory Committee is in the process of recommending new guidelines which would recommend limiting added sugar consumption to no more than 10% of total calories for adults, in alignment with the American Heart Association recommendation. Here is a good summary of these new recommendations. The World Health Organization also recommends limiting added sugar to 10% of total calories and encourages a more conservative 5% of total calories for additional health benefits. Scientists in the U.K. recommend limiting added sugar to no more than 5% of total calories. Keep in mind these are the upper limits, and daily consumption should be kept as low as possible.
*Fructose: The heavy consumption of one particular type of sugar, the monosaccharide fructose, adversely impacts human health, beyond and unrelated to its caloric equivalent, in many ways paralleling the health harms associated with alcohol overconsumption. Fructose (50% of table sugar and typically 55% of high-fructose corn syrup, although concentrations range up to 90%) is a specific cause of increased energy intake, weight gain, and metabolic syndrome. The hepatic metabolism of fructose qualitatively and quantitatively resembles that of alcohol, by promoting: (1) hypertension via uric acid production and lowering nitric oxide; (2) dyslipidemia and hepatic steatosis through excessive de novo lipogenesis and defective lipid oxidation; (3) skeletal muscle insulin resistance and oxidative stress; (4) hepatic insulin resistance and inflammation; and (5) hyperglycemia via hepatic gluconeogenesis. Source: Towards Evidence Based Policies for the Reduction of Dietary Sugars:
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