Sugar doesn’t have the best reputation. It's the bad guy behind surprise cavities, late night dessert binges, inevitable sugar crashes, and those extra pounds that we just can’t seem to lose. Yet, somehow, we can’t get enough. Some sources estimate the average American consumes about 22 teaspoons of sugar per day—more than twice the recommended amount! And some researchers even believe it should be considered a controlled substance. So why exactly is sugar so bad? From adding unnecessary calories to many foods to being a potential cause of weight gain, the reasons go on and on...
Sugar Babies—The Need-to-Know
But not all sugar is automatically bad for us: sugars naturally found in fruits, veggies, and whole grains make up a crucial part of a healthy diet. Where the problems lie (and the risk of cardiovascular diseases and obesity come into play) is with the amount of added sugar in our diets.
Sugar can go by many names, especially when it comes to food labels; high-fructose corn syrup, dextrose, raw sugar, and glucose are just a few of its many disguises. Natural or processed, sugar is a simple carbohydrate that the body uses for energy.
Here's how it all works once that sugar goes down the hatch: Refined sugar is made up of two parts—one molecule of glucose and one molecule of fructose. Breaking down this compound requires more work from the liver, which is responsible for breaking down most of the glucose in the body. Because many types of cells in the body can process glucose, it's much easier for the body to process foods containing only this starch, like bread or potatoes. Putting refined sugars in liquid form like, say, soda or juice, means it hits the liver even quicker than eating something with the equivalent dose of sugar (like whole fruit), and requires the liver to metabolize the fructose and glucose more quickly.
What this means for our bodies isn't so great: Studies have found that when a significant dose of fructose hits the liver of some animals very quickly, a good part of it is converted to fat. Public health: The toxic truth about sugar. Lustig, R.H., Schmidt, L.A., Brindis, C.D. Department of Pediatrics, University of California, San Francisco, CA. Nature, 2012 Feb 1;482(7383):27-9. In humans, this conversion of fat causes insulin resistance (or metabolic syndrome), which often contributes to the development of diabetes. This is not awesome news, since Americans consume 19 percent more added sugar (or any sugar not found in a food’s natural state) now than we did in the 1970s! Maybe it's time to put down the Sour Patch Kids and pick up that apple we mentioned?
Besides promoting weight gain and obesity, recent research suggests overdoing it on sugar (and especially fructose) can lead to many other medical conditions associated with metabolic syndrome, including liver toxicity and cardiovascular disease. Consumption of added sugars and indicators of cardiovascular disease risk among US adolescents. Welsh J.A., Sharma A., Cunningham S.A.,et. al., Nutrition and Health Science Program , Children's Healthcare of Atlanta, Atlanta, GA, Circulation. 2011 Jan 25;123(3):249-57. High-fructose corn syrup: everything you wanted to know, but were afraid to ask., Fulgoni V 3rd, Nutrition Impact, LLC, Battle Creek, MI, American Journal of Clinical Nutrition. 2008 Dec;88(6):1715S. Consumption of high-fructose corn syrup in beverages may play a role in the epidemic of obesity, Bray G.A., Nielsen S.J., Popkin B.M., Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, American Journal of Clinical Nutrition. 2004 Apr;79(4):537-43. Sugar-sweetened beverages, weight gain, and incidence of type 2 diabetes in young and middle-aged women, Schulze M.B., Manson J.E., Ludwig D.S., Department of Nutrition, Harvard School of Public Health, Boston, MA, Journal of the American Medical Association 2004 Aug 25;292(8):927-34. Changes in metabolism may also have an effect on hormonal signals, resulting in damaging effects to the liver (similar to the effects alcohol has). And one study suggests there may even be a potential for sugar abuse when, like alcohol and tobacco, sugar affects hormone levels in the brain, leading to decreased feelings of fullness and increased consumption. Consumption of added sugars and indicators of cardiovascular disease risk among US adolescents. Welsh J.A., Sharma A., Cunningham S.A.,et. al., Nutrition and Health Science Program , Children's Healthcare of Atlanta, Atlanta, GA, Circulation. 2011 Jan 25;123(3):249-57.
Brush That Sweet Tooth—Your Action Plan
In 2018, the Food and Drug Administration will require natural sugar to be labeled separately from processed sugars, hopefully making it easier for consumers to limit the recommended six teaspoons and nine teaspoons of sugar per day to "natural" sources only. Sweetened beverages are notorious for containing high amounts of sugar, resulting in over consumption of calories. Consumption of high-fructose corn syrup in beverages may play a role in the epidemic of obesity, Bray G.A., Nielsen S.J., Popkin B.M., Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, American Journal of Clinical Nutrition. 2004 Apr;79(4):537-43. Even worse, one study even found that drinking beverages sweetened with sugar resulted in weight gain and increased the risk for type 2 diabetes among women. Sugar-sweetened beverages, weight gain, and incidence of type 2 diabetes in young and middle-aged women, Schulze M.B., Manson J.E., Ludwig D.S., Department of Nutrition, Harvard School of Public Health, Boston, MA, Journal of the American Medical Association 2004 Aug 25;292(8):927-34
But don't think that means it's okay to switch to artificially-sweetened drinks—other research suggests diet beverages may have the same effects on weight and even on risk of diabetes. Gain weight by “going diet?” Artificial sweeteners and the neurobiology of sugar cravings. Yang Q. Yale University, New Haven, CT. The Yale Journal of Biology and Medicine. 2010 June; 83 (2): 101-108 Diet soda intake and risk of incident metabolic syndrome and type 2 diabetes in the Multi-Ethnic Study of Atherosclerosis (MESA). Nettleton JA, Lutsey PL, Wang Y, et al. University of Texas Health Sciences Center, Houston, TX. Diabetes Care. 2009 April; 32(4): 688-694 Looks like it's time to refill that water bottle...
Limiting the amount of sugar in your morning routine, eating fruit, and choosing foods, even dessert, with natural sugar only are all ways to cut back on sugar intake. But "cut back" is key—if you want a slice of chocolate cake every now and then, go for it. Just be mindful of how often you indulge.
Jason Edmonds: "The danger isn't just in foods high in fructose-dense sugars. High-sugar diets in general (including glucose, refined flour products, etc.) can also cause problems. There's evidence that suggests replacing dietary saturated fats with high-glycemic-index carbohydrates (like refined grains in bread and pasta) can increase the risk of heart attack. One study followed 53,644 men and women over a period of years and documented their diets and incidence of heart attack (1943 incidents occurred). The investigators found a correlation between substituting dietary saturated fats with low-glycemic-index carbs and reduction in the risk of heart attack. There was no change in risk of heart attack associated with substituting saturated fats with medium-glycemic-index carbs. There was a significant increase in the risk of heart attack associated with substituting saturated fats with high-glycemic-index carbs. Consider that 'low-fat' processed food products might not be a healthy alternative since they often contain higher sugar content than their 'high-fat' counterparts."
John Mandrola: "It's also important to consider the real bad guy about excess sugar: insulin. Insulin has been traditionally known as a hormone released by the pancreas that aids in the metabolism of carbohydrates. It is that, but it is also a potent 'growth factor' as well. Excess insulin, which results from eating excess carbohydrates, results in at least two maladaptive processes in the body: One is that insulin converts sugar to fat (mentioned above), and the second is that insulin promotes atherosclerosis—hardening of the arteries. Obviously, this oversimplifies the actions of insulin, but I think sifting it down these two basic issues—conversion of sugar to fat and artery blocker—serve as a useful means for patients to understand why eating excess refined sugar is so unhealthy. And of course, metabolic syndrome is a downward swirl: the more insulin there is the more resistant the cells become and so goes the higher insulin levels circulating around the body."
While a normal or small amount of sugar shouldn't do much harm, exceed recommended dosages and things could get a little sticky.
Photo by Dan Zim
Originally posted March 2012, updated August 2017.