Our species is programmed to crave and enjoy sugar, but in the modern developed world, that adaptation does not serve us well. Nearly 71% of Americans are overweight, with about 38% obese, per Centers of Disease Control and Prevention 2016 statistics, and sugar no doubt plays an important role.
We’re all well aware that too much sugar is detrimental to our health, but in this article we’ll examine some common points of confusion and the extent of the havoc it can wreak.
Chemistry of Sugar
Saccharides are sugars, one of two main forms of carbohydrate (the other being starches). Carbohydrates are organic molecules consisting of carbon, hydrogen, and oxygen atoms, and are among the three macronutrients (basic dietary components) our body needs to function properly, along with protein and fat.
Simple sugars, also called monosaccharides, are single sugar molecules and include glucose (or dextrose), fructose, and galactose.
Sucrose is a disaccharide; it is composed of two simple sugars, in this case fructose and glucose, fused together. During digestion, the chemical bond is severed and they are then absorbed separately in the small intestine.
Then there are polysaccharides and oligosaccharides, which are different numbers of monosaccharides joined together.
Types of Sweeteners
Sweeteners like honey, agave nectar, the (undeservingly) notorious high-fructose corn syrup, and plain table sugar contain varying amounts of glucose and fructose. There are other types we won’t go into, but here are some popular varieties.
Table sugar/granulated sugar: Made from either sugar beets or sugar cane, table sugar is sucrose, which is 50% glucose and 50% fructose. Molasses is removed, resulting in its being white.
Molasses: A byproduct of the refining process, the sweetness in molasses is derived from sucrose.
Brown sugar: white sugar with some molasses added back in.
High-fructose corn syrup: normally either 42% or 55% fructose (the rest being glucose), per the U.S. Food and Drug Administration (FDA).
Agave syrup (or, inaccurately, nectar): Produced from the juice of the core of the agave plant (the same used to make tequila), this sweetener is sweeter than regular sugar and honey, contains additional calories, and can contain up to 90% fructose (the rest being glucose).
Honey: The ratio of glucose and fructose varies, but according to one source it’s approximately 31% glucose, 39% fructose, 17% water, along with some other carbohydrates, proteins, and trace content.
Maple syrup: Derived from the sap of maple trees, maple syrup varies by grade but is mostly sucrose (50% glucose and 50% fructose); it’s about the same as table sugar.
Brown-rice syrup: Brown-rice syrup is made from whole grain rice treated with enzymes that break down its natural starches into the sugars maltose (two linked glucose molecules), maltotriose (three linked glucose molecules), and a small amount of glucose. It ranks very high on the glycemic index at 98, which measures how quickly carbohydrate-containing foods raise blood sugar (in other words, glucose in blood).
Glucose vs Fructose
Glucose is present in all foods that contain carbohydrates. Corn syrup is mostly glucose. Fructose, which is sweeter than glucose, is also known as “fruit sugar” as it’s the main type of sugar found in fruits.
Glucose and fructose are metabolized by different organs. The brain, liver, muscles, and fat tissue among others metabolize glucose, and it is used for energy by most cells in the body. Fructose, on the other hand, is metabolized primarily by the liver.
Some of the end products from fructose’s metabolism in the liver include triglycerides, free radicals, and uric acid. Triglycerides build up, forming fatty tissue in the liver, and impair liver function, and those released into the bloodstream contribute to fatty plaque lining the inside of artery walls. Free radicals cause damage to cell structures, enzymes, and genes. Uric acid can disable the production of nitric oxide, which serves as a defense against damage to walls of arteries, and causes gout (a painful form of arthritis).
Further, although both glucose and fructose trigger reactions in the body that lead to a feeling of fullness, glucose does so more efficiently. Upon consuming glucose, the pancreas releases insulin, which causes an increase in leptin, a hormone that helps to inhibit hunger, and at the same time suppresses the hormone ghrelin, which (like leptin’s opposite) increases appetite. Fructose, however, does not activate these cues that tell your body you’ve had enough, conducive to overeating.
Is High-Fructose Corn Syrup Worse Than Table Sugar?
It is a common misconception that high-fructose corn syrup poses greater health risks than regular sugar (sucrose); contrary to what its name implies, it is essentially the same. While sucrose is 50% glucose and 50% fructose, high-fructose corn syrup is normally either 42% or 55% fructose (the rest being glucose).
Juice vs Whole Fruit and Vegetables
Sugar from whole fruit and vegetables is far superior to that in pulp-free juice.
Both contain beneficial vitamins, minerals, antioxidants, and plant nutrients (phytochemicals). But juice’s lack of fiber that comes packaged with it in the whole version means reduced amounts of that good stuff, since it’s found in things like the seeds, the stringy membranes separating citrus fruit segments (piths), and skin.
Fiber also helps to slow the absorption of sugar, minimizing spikes of insulin (a hormone that regulates the amount of glucose in the blood) and levels of blood sugar. A 2013 study compared the consumption of certain whole fruits with drinking fruit juice and found the former to be significantly associated with a decreased risk of type 2 diabetes (particularly blueberries, grapes, and apples), whereas the latter was significantly associated with a higher risk.
Because it takes longer for your body to digest fiber, it helps you to feel full longer, reducing your likelihood of overeating.
Dried vs Fresh Fruit
The sugar content as well as fiber is the same for both dried and fresh fruit, but the greatly reduced volume and water make it easier to eat portions of dried fruit with excessive amounts of sugar and calories. Dried fruit often contain added sugars, which put them in the realm of candy, so be sure to check that no sweetener is added. Not even fruit juice concentrate.
Consequences of Excess Sugar Consumption
Here’s just a sprinkling of negative outcomes too much sugar in your diet may produce.
Americans are eating too much sugar, and with its high caloric content, it plays a critical role in development of obesity. However, it is part of a broader picture and is just one contributing factor in the obesity problem; for instance, those downing sugary drinks are likely to be getting inadequate exercise, smoking cigarettes, eating larger portions than is healthful, and so forth. While reducing added sugars in the diet is wise, it is not the sole determinant for achieving healthy weight. A 2016 meta-analysis concluded that sugar (fructose in this case) does not appear to have a unique metabolic ability in leading to weight gain but is harmful in excess. Obesity also appears to be a cause of several types of cancer, and most people with type 2 diabetes are obese.
A major 2014 study that examined the impact of sugar consumption on cardiovascular disease mortality over the course of 15 years found a significant relationship between the two. Participants whose added sugar intake comprised at least 25% of their total daily caloric intake were twice as likely to die from heart disease as those with less than 10%.
In the process of tooth decay, your tooth enamel is softened, which can eventually lead to cavities, holes in your teeth. This is caused by plaque bacteria breaking down sugar in your mouth, creating acids that corrode away your enamel.
Type 2 Diabetes
A 2015 study confirmed the implication of added sugars (particularly fructose) in the development of type 2 diabetes, which is a largely preventable form of diabetes, whereas type 1 is dependent on genetic factors.
The average American eats around 20 teaspoons of sugar per day, which exceeds guidelines set by major governmental and health authorities.
2015 World Health Organization (WHO) guidelines suggest that adults and children limit intake of free sugars (added sugars and those naturally found in honey, syrups, and fruit juices) to no more than 10% of total daily caloric intake, which would be about 50 grams or 12 teaspoons per day. But they go on to advise a further reduction to 5% (about 25 grams, or six teaspoons) for additional health benefits.
The American Heart Association recommends that adult women limit added sugars to six teaspoons or 100 calories per day and that men limit themselves to nine teaspoons or 150 calories per day.
2015–2020 U.S. Dietary Guidelines also recommend that added sugars from any source be limited to no more than 10% of daily caloric intake, which is about 50 grams of sugar for someone consuming 2,000 calories per day.
It is prudent to keep your added sugar intake (as well as fruit juice consumption) to a bare minimum, and if you’re on a tight budget, all the more reason to eliminate it entirely.
Personally, I’d suggest nixing fruit juice from your diet and checking all food labels for added sugar content before purchase. I stick to plain yogurt and add stevia or sucralose sweetener, or just sweeten with frozen fruit microwaved for a minute (cheaper and more convenient). I don’t eat breakfast cereals and instead have plain oatmeal in the morning with add-ins that don’t contain added sugar. I snack on plain nuts rather than nut and fruit mixes that contain a boatload of sugar (I’ve yet to encounter one without added sugar).
What are your favorite foods without added sugars and/or tips for maintaining a low-sugar diet?