Go to any restaurant from a fast food joint to a fine dining establishment and you are likely to find an array of sweeteners available.  A familiar rainbow of white, pink, blue, and yellow have become as commonplace on a table as salt and pepper.  Artificial sweeteners have provided a way for savvy dieters to enjoy a sweet treat without increasing calories and ruining diet efforts.

To This day, about 15% of the American population consumes artificial sweeteners in foods and beverages.  is 2 times the number of people consuming them 20 years ago.  Yet, obesity rates are at an all time high with a continuous upward trend.

It is very counterintuitive that with an increase in the use of artificial sweeteners would come an increase in obesity.  Still, this is an undeniable fact of the current times.  Researchers began to take notice of this trend and decided to investigate whether or not artificial sweeteners were actually causing the obesity epidemic.

Of the studies conducted over the past few years, some have definitively linked artificial sweeteners to weight loss, while others have linked their use to weight gain.  The conflicting research has left many consumers confused as to whether artificial sweeteners will help or hinder their weight loss efforts.  Understanding the research supporting each side can help us make appropriate decisions when it comes to the use of artificial sweeteners.

Artificial Sweeteners = Weight Gain: The Support

1.  Sweet Stimulates Hunger

Milk, which is the sole nutrition source for the first 6-12 months of life, contains the natural sugar lactose.  This sugar has been linked to stimulating an appetite in infants to encourage consumption.  So from birth, humans (and other mammals) are conditioned to associate sweetness with feeding time.  This evidence leads to the notion that artificial sweeteners can actually increase hunger.

2.  Sweetness without Calories Does Not Induce Satiety

Our digestive organs make up a well evolved system that utilizes nutrients and regulates intake.  From infancy, these organs are conditioned to react in a specific way to different nutrients.  For instance, when sugar is consumed, hormones and enzymes are released for digestion, and signal the body to stop eating.

When artificial sweeteners are consumed, the same process begins to take place, however, the sweeteners are not digested the same as sugar because there are no calories to absorb.  Some researchers believe that the body stops sending the signal of satiety because of the alteration in digestion.  Eventually, the body becomes reconditioned to associate sweet tastes with decreased calories, no matter if artificial sweeteners or sugar is the source of sweetness.  This leads to a desire to consume more energy (calorie) rich foods to make up for the “missing” calories.

The most convincing evidence of this comes from a research study out of Purdue University.  In this study, rats that were fed artificial sweeteners in water as a pre-meal ate more chow than rats that were fed sugar-sweetened water before a meal.  This led to the conclusion that artificial sweeteners indeed contribute to an increased appetite.

3.  Psychological Impact

In addition to the physiological impact artificial sweeteners have on food choices, there are also psychological factors.  One study showed that people who knew they were consuming artificial sweeteners ate more calories than those who did not know they were consuming the sweeteners.  Researchers concluded the belief that fewer calories being consumed can lead to later liberalizations in food choices and portion control.

Artificial Sweeteners = Weight Loss: The Support

1.  Eating Fewer Calories Means Losing Weight

Replacing a 150-calorie soda with a 0-calorie soda can no doubt have an impact on calorie intake and weight loss over time.  Artificial sweeteners have allowed people to continue to enjoy their favorite foods and beverages without sacrificing their weight loss efforts.  Studies have shown that people who replace sugar-containing beverages with beverages containing artificial sweeteners decrease their calorie intake by 5%.  Sustaining this decrease in calorie intake can certainly lead to successful weight loss.

2.  Correlation does not Equal Causation

There is no denying that over the past 20 years the rate of obesity has significantly increased.  This has occurred simultaneously with the increased use of artificial sweeteners.  However, this does not necessarily mean that artificial sweeteners are the cause of the increase in obesity.

There are many other factors to consider that may also have affected the current trend.  For instance, there has been an increase in fast food consumption, increased technology leading to decreased physical activity, and a decrease in mandatory physical education in schools.  With so many potential factors, it is impossible to pin just one as the sole cause of obesity.  This includes artificial sweeteners.

3.  Liquids will not Always Satisfy Hunger

It is well documented that it is difficult to satisfy hunger with a liquid.  One particular study examined the difference in hunger ratings between people consuming diet soda versus regular soda.  They found that there were no differences in hunger rankings between the two groups, despite the fact that the people drinking regular soda consumed more calories.  They concluded that calories in liquids did not contribute to appetite control, and artificial sweeteners did not stimulate appetite.

Another study looked at the differences between beverages and foods containing artificial sweeteners.  They found that people who drank diet beverages experienced more hunger than people who ate solid food containing similar amounts of artificial sweeteners and some calories (i.e. sugar-free pie).  From these studies, researchers have concluded that liquids have little impact on hunger no matter the calorie content.  While at the same time, solid foods containing artificial sweeteners can both satisfy hunger and decrease calorie intake.

Conclusion

Both sides of the artificial sweetener debate have strong arguments and evidence to support their beliefs.  So what should be advised when it comes to weight loss and the use of artificial sweeteners?

First, remember, it’s calories that count when it comes to weight loss.  Unlike the rats in the study showing an increased intake with the use of artificial sweeteners, humans have the ability to read labels and make good decisions about what to eat.  Setting a calorie goal and sticking to it is most important, and this may include using artificial sweeteners.

If you are worried about the possibility that artificial sweeteners may increase hunger, pay special attention to how you feel when you use them.  If you notice an increased appetite, try cutting them out for a while to see if it makes a difference.  Research studies may be inconclusive, but you can learn a lot about your personal reactions through individual experimentation.

Lastly, don’t think that adding artificial sweeteners to your diet will be helpful.  It is only useful when products with these sweeteners REPLACE foods and drinks high in regular sugar.  This replacement is what results in decreased calorie intake and weight loss.  Solely adding artificial sweeteners to your diet will not make a difference, especially when it comes to diet drinks that have little to no impact on hunger.

References:

Mattes RD, Popkin BM.  Nonnutritive sweetener consumption in humans: effects on appetite and food intake and their putative mechanisms.  Am J Clin Nutr. 2009;89(1): 1-14.

Bellisle F, Drewnowski A.  Intense sweeteners, energy intake and the control of body weight.  Eur J Clin Nutr. 2007;61: 691-700.

American Psychological Associaiton (Feb 11, 2008).  Artificial Sweeteners Linked to Weight Gain.  Science Daily.  Retrieved Aug 2, 2009, http://www.sciencedaily.com/releases/2008/02/080210183902.htm.

Swithers ES, Davidson TL.  A role for sweet taste: calories predictive relations in energy regulation by rats.  Behav Neurosci. 2008;122(1): 161-173.