Can Diet Make You Fat? The Truth About Artificial Sweeteners

Due to the increasing prevalence of overweight and obesity, there is a strong focus on dietary intervention and energy restriction.

Many strategies focus on improving energy balance to achieve successful weight loss. One of the strategies to lower energy intake is refraining from sugars and replacing them with artificial sweeteners, which maintain palatability without ingesting calories.

Artificial sweeteners are marketed as low-calorie or calorie-free chemical substances used instead of sugar to sweeten foods and drinks to aid in weight loss, but the evidence regarding artificial sweeteners is mixed and controversial.

Artificial sweeteners offer a sweeter taste without calories, and the replacement of sugars with these sweeteners seems promising in reducing sugar and energy intake.

However, several large-scale prospective and population cohort studies have reported that the consumption of artificial sweeteners, particularly in diet sodas, is associated with increased weight gain and abdominal fat over time.

Sweeteners are sugar substitutes that are used to stimulate a sense of sweetness. They are classified as natural sweeteners and artificial sweeteners. 

• Natural sweeteners include sugars, such as glucose and sucrose, and sweet amino acids found in honey, agave nectar, and maple syrup.
• Artificial sweeteners are added to thousands of products, from drinks, desserts, and ready-made meals to cakes, chewing gum, and toothpaste.

Depending on whether they contain calories, artificial sweeteners are further classified as nutritive and nonnutritive sweeteners.

The nutritive sweeteners include monosaccharide polyols (xylitol, mannitol, and sorbitol) and disaccharide polyols (lactitol and maltitol). The nonnutritive sweeteners, known as artificial sweeteners, include substances from different chemical classes that are 30 to 13,000 times sweeter than sucrose.

Artificial sweeteners are metabolized differently and have different properties, including: 

• Sweetness intensity
• The persistence of the sweet taste
• Coating of the teeth
• Aftertaste effects

Currently, six different artificial sweeteners are approved by the FDA as food additives in the United States, namely, saccharin, sucralose, aspartame, advantame, acesulfame-potassium, and neotame.

Various artificial sweeteners are available in the market that is effective at stimulating the sweet taste receptors on the tongue.

Energy intake has increased along with the consumption of animal fat and energy-dense foods, whereas fiber intake has decreased. This dietary shift contributes to the rise of non-communicable diseases, including obesity, type II diabetes mellitus, cardiovascular disease, and cancer.

People often choose noncaloric artificial sweeteners over sugar to lose or maintain weight. Sugar provides a large amount of rapidly absorbable carbohydrates, leading to excessive energy intake, weight gain, and metabolic syndrome.

Research studies have suggested that the use of artificial sweeteners may have a stimulating effect on appetite and may play a role in weight gain and obesity.

Moreover, artificial sweeteners can lead to metabolic disturbance through the disconnect that develops between the amount of sweetness the brain tastes on the tongue and how much blood sugar ends up reaching the brain.

The surface of the tongue is covered by many taste buds, each containing several taste receptors that detect different flavors; when we eat, these taste receptors encounter food molecules.

After detecting a food molecule, there occurs a perfect fit between a receptor and the molecule, which sends a signal to the brain, allowing it to identify a particular taste.

Although artificial sweetener molecules act like sugar molecules to fit on the sweetness receptor, they are generally different from sugar for the body to break down into calories.

As the body cannot break them down, they are considered to have zero calories.

Effect of artificial sweeteners

• Effect on appetite
  • Sugar-sweetened foods trigger the release of certain brain chemicals and hormones related to the food-reward pathway.
  • This pathway is crucial to feeling satisfied after eating and involves brain circuits, such as addictive behaviors and drug addiction.
  • Researchers believe that the lack of calories prevents the complete activation of the food reward pathway, which could cause artificial sweeteners to increase appetite and cravings for sugary food.
  • Therefore, most researchers believe that artificial sweeteners fail to satisfy the biological sugar cravings in the same manner as sugar and could lead to increased food intake.
• Effect on body weight
  • Several observational studies have reported that artificially sweetened drinks are linked to weight gain rather than weight loss, whereas controlled studies report that artificial sweeteners do not cause weight gain and may be mildly effective for weight loss.
• Effects on metabolic health
  • Observational studies link artificial sweeteners to an increased risk of metabolic conditions, such as type II diabetes, heart disease, and metabolic syndrome.
  • In addition, these sweeteners are tied to glucose intolerance and disruption in gut bacteria.