Can we satisfy our sweet craving without taking in excess calories? Can we eat and drink to our hearts delight without packing extra pounds?
These are the promises of artificial sweeteners. Can we gain everything and really expect no consequences? Or, are these promises just sweet nothings?
The are generally two kinds of sweeteners, nutritive and non-nutritive sweeteners.
Nutritive sweeteners, as the name imply provide nutrition or calories when consumed. Sugar is the most common example and provides 4 kcal/gram.
Sugar alcohols, or polyols also provide calories but less than sugar hence they are generally used as “lower calorie” sugar substitute. Their structure resembles sugar and alcohol but they are neither. There are many polyols approved for human consumption. Examples are Sorbitol and Xylitol. They are not completed absorbed in our body and on average, they provide only half the calories that ordinary sugar provides. Although foods that contain sugar alcohols can be labeled sugar-free, they are NOT calorie free. Since they are not well absorbed, they may cause abdominal cramping, gas and may even have laxative effect with excessive consumption.
Artificial sweeteners, also called nonnutritive sweeteners generally do not provide calorie or provide only very minute amount of calorie. They are also referred to as sugar substitutes, alternative sweeteners, very low-calorie sweeteners and intense sweeteners.
The six nonnutritive sweeteners available in the Philippines are saccharin, aspartame, acesulfame potassium, sucralose, stevia and cyclamate. Each of these is regulated by FDA as a food additive and was evaluated based on their safety, chemical stability in various food environments and sensory qualities, such as level of sweetness and odor.
Below is the table summarizing some of the characteristics of these artificial sweetener
It is easy to understand why using artificial sweeteners as sugar substitute is a common strategy for weight loss. The same sweet taste minus the calories equals weight loss. However, this overly simplistic understanding neglects the complex metabolic processes that happens once these non-nutritive sweeteners are consumed. The uncoupling of sweetness and calorie has been the focus of recent studies. There are suggestions that artificial sweeteners increase appetite for sweet foods, promote overeating, and may even lead to weight gain.
Artificial sweeteners on appetite, hunger and food intake
Many studies showed that intake of artificial sweeteners caused increased appetite however there are also studies that failed to demonstrate this appetite-stimulating effect and at least one study even showed appetite suppressing effect. However it’s worthy to note that these studies small number of subjects along with other important limitations.
An important findings consistent with these studies is the compensatory increase in food intake after ingestion of food or beverages containing artificial sweeteners. This compensation can negate any energy deficit of artificial sweeteners and may even lead to net gain in calorie intake.
A meta-analysis involving 12 studies that tested the ability of aspartame in reducing energy intake and to address energy intake compensation showed weighted average of energy intake compensation in the 24 hours that followed aspartame intake was 32%. However, other studies demonstrated higher percentage of compensation. Studies comparing food intake after intake of artificial sweeteners, differ in their findings regarding net energy intake for NNS use relative to the comparison condition with sucrose. In these studies, demonstrated compensation is 10% to 200%.
There are 8 proposed mechanism to this compensatory increase in food intake:
1. Cephalic phase stimulation
The Cephalic Phase refers to the neurohormonal and metabolic changes that happens as reaction to sight, smell, taste and even mere thought of food. This is to prepare the body for the expected influx of nutrients. As taste is one of the triggers, artificial sweeteners may alter the bodies response at this phase.
2. Effects on Gastric Emptying
Artificial sweeteners has osmotic effect and can alter gastric emptying time and subsequently may affect satiety.
3. Gut peptide response
The gut is hormonally active. It secretes peptides that alter satiety and metabolism. Artificial sweeteners can bind to receptors found in the small intestine and may alter secretion of gut peptidases. Alteration of macronutrient composition can also alter peptide secretion.
Improving the taste can increase appetite, stimulate hunger, and reduce satiety.
5. Informed use leading to overcompensation
The knowledge that a person are taking in less calorie may result to over indulgence and rationalization of taking in more food.
6. Loss of signal fidelity
The type and intensity of metabolic response to food is dependent on the sensory properties of signal information such as sweetness and amount of calorie. Intake of artificial sweeteners can cause inaccurate sensory cue of sweetness and calorie contend. This may lead energy regulation disruption and could lead to positive energy balance from overconsumption triggered by this signaling.
7. Activation of reward systems
The reward system is activated is activated with eating. This system is responsible for the feeling of satisfaction and elation after eating a good meal. Artificial sweeteners do not appear to be able to activate this relatively complex system. This loss of activation may result to reward seeking behavior that may translate to increase hunger or cravings.
8. Training the palate/learning to like the familiar
Repeated exposure to artificial sweeteners may cause habituation or increasing preference to sweet taste. This may lead to preference and cravings of high calorie food such as ice cream, desserts, etc.
Overall, the limited human studies suggest that compensation is an important factor to consider when assessing impact on total daily energy intake.
Artificial sweeteners on weight loss
More than half of individuals who regularly consume artificially sweetened beverages do so because they want to control their weight or to lose weight. Surprisingly, very few studies have examined the effectiveness of artificial sweeteners in reducing weight. Findings in both intervention trials and observational studies have been inconsistent.
There a number of small human studies that suggest that substituting sugar with artificial sweeteners is useful in weight management especially in the setting of a multidisciplinary weight loss program. In a review of 16 trials they concluded that despite the compensatory increase in food intake, there is a net 220 kcal deficit per day with use of artificial sweeteners.
However, some studies are challenging this concept and demonstrated weight may actually increase with artificial sweetener use.The Nurses’ Health Study in 1970 found weight gain over eight years in more than 30 thousan women using saccharin. In the early ’80s, the American Cancer Society’s study of 78,694 women found that The San Antonio Heart Study followed 3,682 adults over eight years on the early ’80s. Those who consumed more artificial sweeteners had higher BMIs, and the more that they consumed, the higher the BMI.
A study involving more than 70 thousand women looked into the relationship between the consumption of artificial sweeteners and weight change. Counter-intuitively, this study showed users of these sweeteners were significantly more likely than nonusers to gain weight, regardless of initial weight. Follow up after one year, about 7% more regular artificial-sweetener users gained weight compared to nonusers. Similarly, a population based study published in 2008 reported overall, the change in body mass index was 47% greater among artificial sweetener users than nonusers.[pq]The use of artificial sweeteners for weight loss promotion and control of blood sugar level is not supported by solid evidence.[/pq]
Although there are some data suggesting that substituting sugar with artificial sweetener can promote weight loss, it appears that this benefit is only consistently seen when artificial sweeteners are used in conjunction with a structured multidisciplinary weight loss program. There is substantial compensatory increase in food intake after ingestion of these substances which can negate the initial calorie reduction afforded by this sweeteners, and paradoxically, may even lead to weight gain.
– Dr. Allan Dampil