Is Fructose Bad for You?

How much fructose is too much for a healthy diet? Understand how added fructose in your diet can affect weight and health.

sliced up peaches

Fructose is naturally found in fruits and vegetables, which is why fruit can sometimes satisfy your sweet tooth.

© alvarez | Getty Images

Sugar is not so sweet in the health and wellness world, now more than ever. Its bad reputation stems from research on added sugars, fructose in particular, in foods and beverages, linking it with chronic illness and disease, such as heart disease, obesity, and type 2 diabetes. But even so, Americans, children and adults alike, consume a daily dose an average sugar intake of 17 teaspoons per day, according to the Centers for Disease Control and Prevention (CDC). The American Heart Association recommends consuming no more than six teaspoons of added sugars per day. The Western diet is largely made up of processed foods, most of which contain added sugar.  Fructose, specifically high fructose corn syrup (HFCS), is the most common type of sugar in processed foods. What makes fructose different from other sugars, and should you avoid it?

Fructose 101

Fructose is a naturally occurring sugar in fruits, vegetables, and honey. It also makes up about 50% of table sugar (sucrose), along with glucose. It is also used to make HFCS, which contains similar amounts of fructose and glucose. As the main energy source for our cells, the body breaks down glucose in the cells.  Fructose must be made into glucose by the liver before it can provide energy to our cells. Whereas glucose causes the release of insulin so the body can use glucose for energy, fructose does not trigger insulin, nor the hormones that tell the brain that the body is not hungry. Research suggests that this may lead to overeating and potential weight gain, which can contribute to a number of health problems.

Too Much Added Fructose

Excessive fructose, just like too much of any added sugars, is not healthy. Fructose is converted to glucose in the liver, but if there’s too much, the liver produces uric acid and fat in the form of triglycerides. This, in turn, may increase the risk of fatty liver disease, gout, and heart disease. Too much added fructose has also been associated with insulin resistance, which can contribute to the development of obesity and type 2 diabetes. A recent study links fructose, but not glucose, as the component of added sugar driving metabolic complications, which in addition to insulin resistance and diabetes, include hypertension and premature heart disease. Another recent study suggests it may be the interaction between fructose and glucose in HFCS that increases the risk for heart disease and diabetes. Despite the many studies suggesting its ill-effects, more research is needed for a definitive conclusion against fructose. Many foods with high fructose also contain other sugars, such as glucose, and they tend to be high in calories, which also contribute to obesity and related negative health effects.

Natural Fructose

Fruits, vegetables, fruit juices, and honey contain varying amounts of fructose and glucose. Amounts of each of these two natural sugars vary as well, but generally, it’s about half and half. The difference between eating fructose in its natural form compared to fructose as an added sugar is that whole fruits and vegetables not only have less sugar than foods with added sugar, they are also packed with filling dietary fiber, vitamins, minerals, health-protecting phytochemicals, and water. Consuming too much fructose from fruit and vegetable sources is highly improbable due to the overall balanced nutritional profile of these foods. In fact, studies have shown that eating whole fruits is not only unlikely to contribute to excess calories and weight gain but may even play a role in its prevention and management.

The Bottom Line on Fructose

Excess added sugar intake is not good for health, but it isn’t yet clear whether fructose alone is to blame. More research is needed. Fructose in its natural form—in fruits and vegetables—remains a simple way to satisfy your sweet tooth and load up on health-promoting vitamins, minerals, and phytochemicals.

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Kristen N. Smith, PhD, RDN, LD

Kristen N. Smith, PhD, RDN, LD, has been the Executive Editor of Environmental Nutrition since 2018. As a Registered Dietitian/Nutritionist, Kristen is experienced in the areas of weight management, health promotion, and … Read More

View all posts by Kristen N. Smith, PhD, RDN, LD

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