Does Aspartame cause weight gain?

Aspartame is one of the more controversial sweeteners used in food products.  A common sweetener in ‘diet’ and ‘sugar-free’ products, and used under various brand names as an artificial sweetener for use in beverages or cooking, aspartame is promoted as a good alternative to sugar without the calories.  Whilst its certainly true that aspartame has a very low calorie content, and therefore seen as appropriate for weight loss, many sources claim it can in fact responsible for weight gain, in addition to numerous other side effects and diseases.

What is Aspartame?

Aspartame is a protein based sweetener, designed to replace sugar.  It is used frequently around the world in various foods and beverages and is the most common artificial sweetener used in the US. Products that contain aspartame include diet soda, chewing gums, candy, yogurt and other diet food products.  It can also be found in some medicines and multivitamins. Although it is about 200 times sweeter than sugar, it contains significantly less calories than sugar, making it an attractive option for dieters.  A diet soft drink sweetened with aspartame, for example, contains about 150 calories less than the normal variety.

Aspartame sweetened products are commonly recommended for patients trying to lose weight as a method of reducing calorie intake, but also to diabetic patients who are trying to moderate carbohydrate intake.

Safety of aspartame

The media has perpetuated a huge number of supposed health dangers accompanying the consumption of aspartame.  These range from headaches, dizziness and memory loss to cancer, depression and anxiety.  However, few of these claims are backed by scientific evidence.  A 2007 report published in Critical Reviews in Toxicology, analysing evidence from epidemiological and cohort studies done before this period stated that there was no evidence to suggest aspartame was carcinogenic, or had any effect on the nervous system.  The study concluded that consumption of aspartame was safe in current levels of consumption.

Aspartame and weight loss

A low calorie alternative to sugar

As a low calorie alternative to sugar, aspartame is promoted as a useful tool in weight control.  By replacing high sugar foods like soft drinks, candy and added sugars with this lower calorie alternative, consumers are lowering their overall calorie intake, which is essential for weight loss.  However, along with the myriad of alleged health risks associated with consuming aspartame, it is frequently reported that it causes increased appetite and cravings for sweet foods and thus can contribute to weight gain in the long term, due to increased calorie intake through other food sources.

Does it increase appetite?

It has been suggested that the sweet taste of aspartame sweetened foods cause the body to expect a rush of sugar.  When it does not receive this boost in glucose levels, the body can start to crave sugar, leading to a desire for sweet foods or increased appetite.   Whether this in fact true is an area of some controversy.  In the past, the majority of studies into the effect of aspartame on hunger have suggested that there is no change after the consumption of aspartame, compared with sugar sweetened products.  A review of studies done in this area in 1993 suggested that aspartame intake had no effect on food intake and hunger levels.  Variation that was seen in a few studies was put down to the fact that measuring hunger is very subjective and difficult to measure.   Similarly, weight gain and loss can be attributed to any number of factors which are difficult to control in a scientific study; hence, whilst the majority of studies suggest no change in eating behaviour or weight gain with aspartame consumption, it is difficult to gain conclusive results either way.

The effect of aspartame on blood sugar levels

This same 1993 review also noted that there was generally no effect on insulin and blood glucose levels, which are important factors in the determination of hunger, when aspartame was consumed.  However, more recent studies have suggested that this may not be completely accurate.  A 1999 study published in The British Journal of Clinical Nutrition, found a wide range of blood glucose levels in response to aspartame consumption.  This was suggested to be caused by individual differences, possibly due to the perception of sweetness of the product. The study also demonstrated a relationship between blood glucose responses and food intake for the remainder of the day.    Similarly, a 2007 study in patients with Type 2 Diabetes found a similar blood sugar and insulin response following an aspartame sweetened breakfast to sucrose sweetened one.  These results suggest that aspartame may in fact have an effect on blood sugar, and hence appetite, contrary to the results of previous studies.  It is still unclear what  exact effect aspartame may have on blood sugar levels and how this may contribute to appetite and weight gain and further studies are needed in this area.

In conclusion

Aspartame is considered safe by the FDA, and there is no conclusive evidence supporting the perpetrated dangers of the substance.  Similarly, whilst the majority of studies have found no link between consumption of aspartame and appetite or weight gain, there is still some discrepancy as to the effect on blood sugar levels in the body.  For those who are in the habit of consuming large amounts of high sugar foods such as soft drinks, switching to diet versions containing aspartame may be beneficial for weight management, as calorie intake is likely to be reduced.  However, it must be stressed that the best drink for weight loss is water, as it is totally calorie free and has no adverse effects.

References used in this article.