Is diet soda associated with weight gain?

From the Guidelines

Diet soda is associated with weight gain, and its consumption should be discouraged, especially among children and adults who are trying to manage their weight. The most recent and highest quality study, published in 2020 in the journal Advances in Nutrition 1, suggests that low-calorie sweetened beverages, including diet soda, may increase the risk of obesity and other disease risk factors. A meta-analysis included in this study found that the pooled relative risk for obesity in individuals consuming artificially sweetened soda was 1.59 (95% CI: 1.22,2.08). Another study published in 2019 in the journal Pediatrics 1 found that the use of nonnutritive sweeteners, such as those found in diet soda, may lead to weight stabilization or a small degree of weight loss in the short term, but the long-term effects are unknown.

Some of the key findings from these studies include:

• A meta-analysis of prospective studies found that higher consumption of noncaloric beverages, including diet soda, was associated with a greater incidence of type 2 diabetes, by 25% (95% CI: 18,33%) and 8% (95% CI: 2,15%) per 1 serving/d, before and after adjustment for adiposity, respectively 1.
• A systematic review and meta-analysis of trials and prospective cohorts concluded that replacing sugar-sweetened beverages with low-calorie sweetened beverages, including diet soda, could contribute to a modest weight loss, but the evidence was criticized for its lack of statistical power and short duration 1.
• The American Heart Association Nutrition Committee recently reviewed the evidence and concluded that the use of other alternatives to sugar-sweetened beverages, with a focus on plain, carbonated, or unsweetened flavored water, should be encouraged, and that prolonged consumption of low-calorie sweetened beverages by children is not advised 1.

Overall, the evidence suggests that diet soda is not a healthy alternative to regular soda and may actually contribute to weight gain and other health problems. Therefore, it is recommended to limit or avoid diet soda consumption and instead choose healthier alternatives, such as water, unsweetened tea, or sparkling water with a splash of fruit juice.

From the Research

Diet Soda and Weight Gain

• The relationship between diet soda consumption and weight gain is complex and has been studied extensively 2, 3, 4, 5, 6.
• Some studies suggest that diet soda consumption may be associated with a higher risk of weight gain, particularly in individuals who are already overweight or obese 4, 6.
• A study published in the Journal of the Academy of Nutrition and Dietetics found that soda consumption, including diet soda, was associated with weight gain over time 6.
• Another study published in the Clinical Journal of the American Society of Nephrology found that diet soda consumption was associated with a higher risk of end-stage renal disease, which may be related to weight gain and other metabolic factors 4.

Mechanisms and Associations

• The exact mechanisms by which diet soda consumption may contribute to weight gain are not fully understood, but may involve factors such as:
  • Artificial sweeteners affecting glucose metabolism and appetite regulation 2
  • Diet soda consumption being a marker for overall poor dietary habits and excess energy intake 6
  • Social and environmental factors influencing diet soda consumption and weight gain 3
• Studies have also found associations between diet soda consumption and other health outcomes, such as type 2 diabetes, cardiovascular disease, and certain types of cancer 2, 4, 5.

Knowledge and Beliefs

• Adolescents' knowledge and beliefs about the health risks of diet soda consumption vary, with some studies suggesting that they may not fully understand the potential health consequences 5.
• Public health interventions may be necessary to educate individuals about the potential health risks of diet soda consumption and promote healthier beverage choices 5.