Aspartame and Weight Management

By Jennie McCary
Aspartame and Weight Management
Does aspartame make you gain weight? The simple answer is no. You gain weight when you consume more calories than you burn off through physical activity.
April 2, 2008

The following two questions came into the Aspartame Resource Center. We asked Jennie McCary, MS, RD, LD to respond.

Does aspartame make you gain weight?

The simple answer is no. You gain weight when you consume more calories than you burn off through physical activity. As a low-calorie sweetener, aspartame contributes little to no calories, resulting in products much lower in calories compared with those sweetened with sugar. For this reason using it as part of a healthy, balanced diet in combination with regular physical activity and behavior modification can aid in weight loss and management.

In fact, results of a study published in the American Journal of Clinical Nutrition comparing a group of obese adult women who consumed aspartame-sweetened beverages as part of a multidisciplinary weight-control program with a group that did not, showed that aspartame users lost significantly more weight overall and regained less weight one to two years later.

A more recent review of 16 studies demonstrated that using foods and beverages sweetened with aspartame instead of sugar results in a significant reduction in both calorie intake and body weight among healthy adults. Considering the average calorie intake of adult men and women, the authors translated the mean reduction of 10% of calorie intake to a daily calorie deficit of 222 calories. This is enough of a calorie deficit to result in a meaningful weight loss over time or to counteract the gradual weight gain that generally occurs in adulthood. Using aspartame-sweetened products can help drive down calories in favor of weight loss or maintenance. To demonstrate, here are some eye-opening calorie-saving substitution examples:

  • A switch from a 12-oz can of regular soda to diet soda can save 150 calories a day and potentially result in a 15 pound weight loss in one year!
  • Replacing 2 tsp. of sugar in your 3 cups of coffee or tea with 1 packet of tabletop sweetener can save 100 calories a day and help you lose 10 pounds in one year.

Questions have been raised as to aspartame's effectiveness as a weight management tool. It's been argued that aspartame use increases hunger and food intake because of the sweet taste, and that the body compensates from any calorie deficit resulting from aspartame use. Here are the facts behind those claims:

  • Most scientific investigators report no change or decreased ratings of hunger with aspartame consumption. While some studies show increased hunger ratings this is not translated into an increase in food intake.
  • Short and long-term studies show that aspartame use is associated with a reduction or no change in food intake.
  • A few short-term studies show compensation for the calorie deficit when aspartame-sweetened products are substituted for those sweetened with sugar. But the amount (< 1/3 of the calorie reduction) was low enough that people still lost weight using the aspartame-sweetened products.
  • The claim that sugar substitutes cause weight gain is based on few animal studies with several criticisms from nutrition experts; no human study has ever linked aspartame with weight gain.

A recent study linking low-calorie sweeteners and weight gain contradicts human studies that show they are beneficial for weight control in conjunction with a well-balanced diet and active lifestyle. In the battle against weight gain, it's the calories that matter. As a sugar substitute, aspartame can help individuals lower energy intake and if on a weight control plan, effectively maintain a reduced-calorie diet.

Does aspartame contain carbohydrates?

No, aspartame itself is actually protein-based and is digested as a protein. This makes it an ideal ingredient for individuals with diabetes and others managing their carbohydrate intake. Additionally, when broken down into the amino acids aspartic acid and phenylalanine, aspartame contributes few to no calories. Like other high intensity-based tabletop sweeteners, aspartame-based sweeteners generally are formulated with a very small amount of a carbohydrate bulking agent. For example, in the case of Equal® packets, one packet contains less than 1 gram of carbohydrate and contributes zero calories to the diet, but provides the sweetness of 2 teaspoons of sugar.

Together, these properties lend aspartame-sweetened products a role in helping individuals reduce calories, total carbohydrates, and added sugars without sacrificing the sweet taste. A national online survey revealed that 7 out of 10 Americans report they are trying to consume less sugar (IFIC) and according to the Calorie Control Council, cutting down on foods high in sugar is the most common tactic used by dieters as a weight control strategy.

Basically, aspartame is a sweet alternative to sugar and high calorie foods and beverages for the millions of Americans trying to consume less sugar and balance their calorie bank for overall health, diabetes, and weight management.


Jennie McCary, Albuquerque, NM, is a registered dietitian and provides expert counsel to the Aspartame Resource Center.


Aspartame and Weight Management

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