Do Diet Sodas Really Cause Weight Gain?

Diet soda can cause weight gain because of the following:

• Diet soda tricks the brain into thinking you have less sugar in your system, meaning you may crave more sugar throughout the day.
• You do not feel full after drinking soda because the body does not treat liquid calories like calories from solid foods. As a result, you may be tempted to eat more after consuming a high-calorie drink.
• Aspartame or other artificial sweeteners are the main culprits for weight gain. Aspartame (Nutrasweet, Equal, and Sugar Twin) is an artificial sweetener that is 160 to 220 times sweeter than sucrose high in calories. Artificial sweeteners can lead to miscalculation of calories that you consume, leading to slower metabolism and higher weight gain.

Animal studies have found that at least one artificial sweetener (aspartame) may affect a part of the brain that signals the animal to stop eating. 

A 2017 study published in the journal Obesity Research & Clinical Practice found that rats who drank a carbonated beverage (regular or diet) ate more food and gained weight more than rats who drank water or flat soda. The study found that ghrelin levels in the stomach were higher after the rats consumed carbonated beverages compared to noncarbonated drinks. Ghrelin, also called hunger hormone, increases appetite by signaling hunger to the brain.

In addition, human studies have found that people who drink artificially sweetened drinks tend to gain more weight. The same 2017 study experimented with the effect of carbonated drinks on humans (20 students). The study found that the students who drank any kind of soda, diet soda or regular soda, had increased levels of ghrelin hormone compared to students who drank only water or flat soda.

Both animal and human studies suggest that due to the increased ghrelin release, consumption of carbonated drinks is linked to increased food cravings and weight gain.

Common ingredients found in most diet sodas include:

• Carbonated water. Carbonated water is made by dissolving carbon dioxide in water under pressure.
• Sweeteners. Even if there is no regular sugar added, artificial sweeteners that may be used include:
  • Aspartame
  • Saccharin
  • Sucralose
  • Herbal sweeteners, such as stevia
• Acids. Certain acids are added to the sodas to increase the tartness of the product. Some of them include:
  • Citric acid
  • Malic acid
  • Phosphoric acid
• Colors. Commonly used colors in diet soda include:
  • Carotenoids
  • Anthocyanins
  • Caramels
• Flavors. Commonly used natural juices and artificial flavoring agents in diet soda include:
  • Fruits
  • Herbs
  • Cola
• Preservatives. Preservatives help maximize the shelf life of diet sodas. Potassium benzoate is a commonly used preservative in diet soda.
• Caffeine. Caffeine is often added to carbonated beverages to make them addictive. A can of Diet Coke contains 46 mg of caffeine, and a can of Diet Pepsi contains 35 mg.

While drinking diet soda once in a while may not necessarily cause weight gain, you should not rely on it to lose weight. Monitor your calorie intake throughout the day and observe how it impacts your weight.

Ideally, it is best to limit the intake of all kinds of carbonated drinks. Better options include plain water, unsweetened tea, or fruit-infused water.

Another reason why people may quit drinking diet soda is the concern regarding the link between artificially sweetened beverages and serious diseases such as heart disease, kidney disease, and certain cancers.

However, there is no strong evidence to support the claim that drinking diet soda is associated with an increased risk of these diseases.

• Drink more water. Drink more water when you have soda cravings because it could be confused with thirst.
• Find alternatives. If plain water is too boring, find alternatives for diet soda such as:
  • Infused sparkling water
  • Kombucha
  • Sparkling green tea
  • Herbal or fruit teas
  • Coconut water
• Avoid getting too hungry. Do not go hungry for a long time because hunger is the major cause of soda cravings.
• Snack on healthy foods. If you crave sugar, opt for healthy sweet snacks such as fruit or sugar-free chewing gum.
• Manage stress. Control your cravings by managing stress and distracting yourself with other relaxing or pleasurable activities.