Sugar: How Much Is Too Much?

Sugar is being demonized — should it be? Understanding the science can help you make informed decisions about its place in your diet.

The basics of sugar metabolism

Table sugar, or sucrose, is composed of one unit of the carbohydrate fructose and one unit of the carbohydrate glucose. Fructose is what sets sweet foods like candy apart from other carbohydrate-rich foods like rice and potatoes, whose main source of carbohydrate is pure glucose. While any cell in the body can break down glucose for energy, liver cells are the primary metabolizers of fructose. This is potentially problematic because if you eat more fructose than the liver can handle, it turns it into fat in the form of triglycerides. High levels of triglycerides can damage the liver and pancreas and lead to plaque buildup in the arteries, which increases your risk of cardiovascular disease. Overloading the liver with fructose also leads to fat deposits around the organs (visceral fat). The more visceral fat you have, the more at risk you are for developing chronic diseases such as type 2 diabetes. Sugar can further disrupt weight management by interfering with your hunger hormones. It has been linked to higher levels of ghrelin, which increases appetite, as well as to disturbances in insulin and leptin signaling, which are involved with energy storage and appetite regulation. 

Distinguishing between different types of sugars

It’s important to take a minute here to distinguish between natural sugars, free sugars, and added sugars. Natural sugars are those present in organic forms in foods such as fruits, vegetables, and dairy products. Free sugars, as defined by the World Health Organization (WHO), are “all monosaccharides and disaccharides added to foods by the manufacturer, cook or consumer, plus sugars naturally present in honey, fruit juices and syrups.” Free sugars also encompass added sugars, which are those that are artificially put in products by food manufacturers. It can be hard to tell how much sugar is added to a food, because nutrition facts labels currently don’t always distinguish between total sugars and added sugars. However, in 2016 the Food and Drug Administration (FDA) approved a series of revisions to the nutrition facts label that will change this. These changes have been phased in over the past few years and should be complete by July 1, 2021.

What about fruit?

All fructose molecules are treated equally by the body, but the vehicle by which sugar is delivered can make a difference. Let’s look at an example. A medium apple contains around 20 grams of sugar. However, it also contains nearly a quarter of your daily recommended intake of fiber. This fiber slows down the release of sugar into the bloodstream, thus lessening its impact on the liver. Juice, on the other hand, has little to no fiber, which means that all that sugar hits your liver at once. It also takes several apples to make a glass of juice, which concentrates the sugar that you’re consuming. Bottom line is, it’s better to eat your calories than to drink them.

How much is too much?

I keep saying “excess sugar consumption.” What does this really mean? The WHO recommends that adults consume no more than 10% of their daily calories as free sugars. For a 2000 calorie diet, that’s about 50 grams per day, or 12 teaspoons (for perspective, a sixteen ounce coke provides 52 grams of sugar). The American Heart Association gets even stricter, advising no more than 6 teaspoons per day for women and 9 teaspoons per day for men.

Final thoughts

Cutting back on sugar has made me feel better personally. I used to have quite a sweet tooth; now, I mostly limit free sugar to a small piece of dark chocolate after dinner. Since doing this, I’ve noticed that I’ve had fewer cravings and my energy levels have been more stable. Of course, I’m not perfect (nor would I want to be). I’m not going to turn down homemade pie, and Ben & Jerry’s just hits the spot sometimes. I’m not saying that we should cut out sugar completely — I certainly don’t. However, the research that I’ve done over the past few years has convinced me to be cautious.