Sugar Substitutes Promote Weight Gain? Fat Chance.

Editors note: Another guest has decided to take the podium―Lyn O’Brien Nabors, president, Calorie Control Council takes issue with a recent article in the Journal of the American Medical Association that implies low- and no-calorie sweeteners are making us fat.

It is most disconcerting that the Journal of the American Medical Association (JAMA) would publish an article such as “Sugar Substitutes Linked to Weight Gain,” by Tracy Hampton.  The JAMA article reviews a PurdueUniversity study by Swithers and Davidson (published in Behavioral Neuroscience), whichalleges a link between low-calorie sweeteners and weight gain.  Not only are there many flaws in the Swithers and Davidson study (conducted in a small number of rats) but Ms. Hampton fails to mention the many human studies, which have shown that low-calorie sweeteners can be helpful in weight control. 

In addition, contrary to Ms. Hampton’s remarks, the study by Bellisle and Drewnowski, concluded that low-calorie (or no-calorie) sweeteners may be of help in resolving the obesity problem.  The Bellisle and Drewnowski study, published in the European Journal of Clinical Nutrition, evaluated a variety of laboratory, clinical and epidemiological studies on low-calorie sweeteners, energy density and satiety.  Their findings, based on extensive studies in humans, are completely at odds with the Swithers and Davidson study.

Although not magic bullets, low-calorie sweeteners can help people reduce their calorie (energy) intake.  “Low-calorie sweeteners reduce the energy of most beverages to zero and lower the energy density of many foods,” according to Dr. Adam Drewnowski, Director, Center for Public Health Nutrition at the University of Washington.  “Every dietary guideline these days tells us to bulk up, hydrate, and consume foods with fewer calories but more volume.”

Among criticisms of the Swithers and Davidson study identified by nutrition experts are:

• Small sample size.  The original clinical study by Rogers and Blundell (1989), not cited in this report, used 24 humans.  The present study is based on 27 rats.  Only 9 of these rats were in the saccharin fed group upon which Swithers and Davidson based their conclusions.
• Preabsorptive (“cephalic phase”) insulin release, the body’s supposed reaction to non-caloric sweet taste, is cited as the potential mechanism for overeating.  The problem is that there is no cephalic phase insulin release in humans following the ingestion of aspartame, as demonstrated by Abdallah et al (1997).
• A recent study, also based on rats, showed that any flavor associated with a lack of calories led to overeating – even salt.  However, that effect was observed only in very young rats (4 weeks) and disappeared 4 weeks later.
• Findings in animal (e.g., rat) studies are not necessarily applicable to humans.  Generally, clinical studies with humans follow animal studies – not the other way around.
• Some have blamed “sweet tooth” and sugar calories for rising obesity rates.  Others now blame “sweet tooth” and the absence of sugar calories for rising obesity rates.  The human desire for sweet taste is an innate reflex that is present at birth: it is not learned, it is not acquired, it is not conditioned – and it is not going away anytime soon.

Swithers and Davidson oversimplify the causes of obesity -- which are multi-factorial.  Although there has been an increase in the use of “sugar-free” foods in recent years, portion sizes have also increased, physical activity has decreased and overall calorie intake has increased.  

Several studies conducted in humans have shown that low-calorie sweeteners and the products that contain them can be useful tools in weight control.  For example, a study conducted by Dr. George Blackburn, published in the American Journal of Clinical Nutrition, investigated whether the addition of aspartame to a multidisciplinary weight control program would improve weight loss and long-term control of body weight in obese women.  One hundred sixty-eight obese women aged 20 to 60 years were studied over a two-year period.  The researchers found that participation in this multidisciplinary weight control program including the use of aspartame-sweetened foods and beverages not only facilitated weight loss, but long-term maintenance of a reduced body weight.

A 2007 study published in Pediatrics found that using sucralose or sucralose sweetened beverages as well as increasing activity helped maintain and lower body mass index for children participating in the “Families on the Move” program.  Additionally, a study published in the Journal of Food Science found that people who use reduced-calorie products (containing low-calorie sweeteners) not only had a better quality diet but also were more likely to consume fewer calories than those who did not use reduced-calorie products.

“Rising obesity rates have now been linked to the presence of sugars in the food supply and to the absence of sugars from the food supply,” noted Drewnowski.  “Consumers find it difficult to know who to believe.  In the final analysis, all health experts agree that weight loss is best achieved by a combination of reducing caloric intake, lowering energy density of the diet, and increasing physical activity.  By all accounts, low-calorie sweeteners do help.  Suggesting that low-calorie sweeteners actually cause people to gain weight is an irresponsible direct application of rat models to dietary counseling and to public health.”

Especially in light of the wealth of human data demonstrating the value of low-calorie sweeteners in weight control, hypothesizing on the basis of nine saccharin fed rats that low-calorie sweeteners actually make people gain weight is a gross example of animal study theory overshadowing basic common sense.

     -Lyn O’Brien Nabors