Artificial Sweeteners Does Aspartame cause Weight Gain?

In the last issue, I reviewed the regulations, metabolism, and safety of aspartame. Aspartame was approved for general use in 1981 by the FDA and has been studied exhaustively to show the safety of it. Aspartame breaks down into two amino acids and methanol, all of which are consumed in larger amounts in normal foods. In this issue I will review aspartame and its effect on weight gain according to the scientific literature.

Authoritative figures such as Dr. Oz and Dr. Mercola make the claims that artificial sweeteners (aspartame specifically) trick the brain into being more hungry due to a sweet taste not accompanied by a specific amount of calories (1). They claim that this confusion will cause an increase in weight gain. While this idea may make sense at first, the scientific literature does not support this notion. In fact, the totality of the literature shows a neutral to slightly positive effect on weight loss in regards to aspartame and artificial sweeteners.

The evidence to support the claim that aspartame and artificial sweeteners do not cause an increase in weight gain is abundant. A study (2) in the American Journal of Clinical Nutrition in 2013 showed that replacing caloric beverages with water or diet beverages resulted in weight loss in adults equally. Another study (3) that was published in 2002 compared beverages containing sucrose to beverages containing artificial sweeteners (54% of which were aspartame). The study found that the group consuming sucrose sweetened beverages had an increase in energy intake, body weight, fat mass, and blood pressure after 10 weeks. The artificial sweeteners group did not have an increase in any of those parameters. A meta-analysis (4) conducted in 2010 was published in the International Journal of Pediatric Obesity and reviewed 18 studies regarding artificial sweeteners and their metabolic effect in youth. This meta-analysis concluded that “there is no strong clinical evidence for causality regarding artificial sweetener use and metabolic health effects”. This supports the claim that artificial sweeteners do not cause weight gain.

A meta-analysis study (5) in 2014 looked at low-calorie sweeteners and body weight composition. They concluded that “In RCTs (Randomized Control Trials), LCSs (Low Calorie Sweeteners) modestly but significantly reduced all outcomes examined, including body weight, body mass index, fat mass, and waist circumference.” They also drew the conclusion that low-calorie sweeteners can result in a modest amount of weight loss and can be a potentially useful dietary tool for weight loss. A study (6) published in 2014 compared artificial sweeteners and water in a 12 week weight loss program. The artificial sweetener (AS) group reported “significantly greater reductions in subjective feelings of hunger than those in the water group during the 12 weeks”. The AS group lost more weight in comparison to the water group. They lost 13 pounds whereas the water group lost 9 pounds. This study shows that not only do artificial sweeteners not cause weight gain, but they may be a useful dieting tool.

In conclusion, the idea that aspartame and artificial sweeteners cause an increase in weight gain is not supported by the literature as a whole. In randomized control trials aspartame and artificial sweeteners show a neutral to slightly positive effect on weight loss.



2. DF T, G T-M, E L, et al. Replacing caloric beverages with water or diet beverages for weight loss in adults: main results of the Choose Healthy Options Consciously Everyday (CHOICE) randomized clinical trial.: American Journal of Clinical Nutrition; 2013.

3. A R, TH V, AC M, A A. Sucrose compared with artificial sweeteners: different effects on ad libitum food intake and body weight after 10 wk of supplementation in overweight subjects. American Journal of Clinical Nutrition2002.

4. RJ B, MA dB, KI. R. Artificial sweeteners: a systematic review of metabolic effects in youth.: International Journal of Pediatric Obesity; 2010.

5. Paige M, Vanessa P. Low-calorie sweeteners and body weight and composition: a meta-analysis of randomized controlled trials and prospective cohort studies. American Journal of Clinical Nutrition2014.

6. Peters JC, Wyatt HR, Foster GD, et al. The effects of water and non-nutritive sweetened beverages on weight loss during a 12-week weight loss treatment program. Obesity2014.

Written by Brandon McGuire
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