Health Effects of Fructose and Other Sugars

When sugar is brought up in a conversation about diet and health it is often done so with grave concern. When the new line item for added sugars begins to appear on the revised Nutrition Facts label, more attention will be brought to the added sugar content of foods.

Sugar has been blamed for obesity, diabetes, dyslipidemia and most recently heart disease. Some individuals may be genetically predisposed to these diseases; however, incorporation of diet and lifestyle modifications can improve these conditions and should  be discussed with patients as part of a comprehensive treatment plan.

What We Know

  • Sugar is a simple carbohydrate that provides four calories (energy) per gram. It is both naturally occurring and added to some foods or beverages.
  • Calories need to be balanced with activity in order to maintain a healthy body weight. Diet and activity trackers may help patients remain mindful about their habits each day. However, it can be helpful to remind patients that individual days of small imbalances should not deter them, as a healthy lifestyle is a long-term change.
  • No matter the type of sugar, the nutrition profile is similar (honey contains insignificant amounts of vitamins). One can argue that “all calories are not created equal”, but we definitely know that all excess calories are related to obesity, not just those from sugars.
  • Simple sugars are quick sources of energy and will elevate blood glucose levels. Simple sugars are not a good choice for the daily diabetic meal plan. Adding some protein and fat to each meal, along with carbohydrates, helps to balance the meal and overall nutrition. Moreover, protein and fat promote satiety so you feel full longer.
  • Sugars can make some foods more palatable. Palatability of foods can indirectly impact diet quality because nutrients can only be obtained when foods are well accepted. Adding sugars to high fiber foods such as oats, cooked vegetables (squash, carrots, etc.) or granola bars, and to milk or yogurt, can help encourage people to include these foods in their diet and ensure they achieve an overall healthy diet. For example, children who consume milk have a higher diet quality than children who do not, and allowing flavored milk may be one way to encourage milk consumption.
  • We know that most people enjoy some amount of sweet foods or beverages from time to time but it is recommended that a healthy diet limits sugars. The American Heart Association recommends no more than 6 and 9 teaspoons of sugar per day for women and men, respectively. This is equivalent to 100 calories for women and 150 calories for men a day (6-9 teaspoons of sugar per day for women and men, representing about 5-7 percent of total calories, respectively.) This guideline is a bit more conservative compared to the more liberal limit set by the World Health Organization, which recommends that no more than 10 percent of daily total calories (or about 200 calories based on a 2000 calorie diet) should come from sugar. As with any dietary prescription, sugar intake should be individualized based on age, personal activity and health goals, and overall diet quality.
  • We also know that healthy diets or therapeutic meal plans are attainable even with some added sugars.

What about Fructose

Much discussion has ensued regarding how the metabolism of fructose may impact health as compared to other sources of sugar. Fructose is rarely consumed without the presence of glucose, and this is important when considering real-life metabolic effects. High fructose corn syrup (HFCS) was singled out during the early part of the 21st century as a potential “cause” of the increasing incidence of obesity, but it’s clear that it has no differential effect on blood glucose, insulin, or other hormones, compared to sucrose (it is a misnomer that high fructose corn syrup is higher in fructose than honey or table sugar; i.e., cane or beet sugar. They are essentially equal in fructose).

Several randomized clinical trials found no significant effect of sugar, fructose, or HFCS on body weight when replaced in an isocaloric exchange with other calorie-containing nutrients. That is, total caloric intake influences weight control, blood pressure, and diabetes management more so than any one specific nutrient. Singling out fructose appears to have no merit.

Sugar-sweetened beverages (SSB) are often the first thing you think about when you ask your patients about the sugar in their diet. SSBs can contribute excess calories, and should not be used routinely in meal planning for anyone with metabolic syndrome, high triglycerides, diabetes (although are useful during hypoglycemic episodes), or those who are overweight or obese. Studies have shown no differential effect of sugar-sweetened beverages and adipose tissue inflammation, for instance. These beverages should not displace other more nutritious foods or beverages, but they can fit into a diet, depending on age, activity level, and lifestyle. For individuals that appear to displace other foods and beverages, low-calorie sweetened beverages improve diet adherence and weight loss.

When advising patients about their diet and sugar consumption it is important to consider their current medical condition and total calorie needs which vary based on age, height, weight, gender, and activity level. Help your patients understand the importance of maintaining a healthy weight by balancing calories with physical activity. If a diet is low in quality, and high in a particular nutrient, including carbohydrates (sugar), this needs to be modified. If a diet is adequate in vitamins, minerals and macronutrients, and weight is reasonable, then sugar intake may not be a significant cause for concern. Do not hesitate to refer patients to a registered dietitian who can provide your patients with comprehensive meal plans specific to their caloric and micro- and macronutrient needs.


Rosanne RustRosanne Rust MS, RDN, LDN is a registered, licensed dietitian-nutritionist with over 25 years experience. As a Nutrition Communications Consultant  she delivers clear messages helping you understand the science of nutrition so you can enjoy eating for better health. Rosanne is the co-author of several books, including DASH Diet For Dummies® and the The Glycemic Index Cookbook For Dummies®. A wife, and mother of 3 boys, she practices what she preaches, enjoying regular exercise, good food and festive entertaining. Follow her on Twitter @RustNutrition.