Zero-Cal Sweeteners & Weight: What WHO and Trials Say

Published 8/17/2025

Packets of various non-sugar sweeteners next to sparkling water

Non-sugar sweeteners (NSS) like sucralose, aspartame, stevia, and monk fruit deliver sweetness with few or no calories. Should you use them while managing weight?

What WHO Says

In 2023, the World Health Organization (WHO) issued a conditional recommendation against using NSS to control body weight or reduce noncommunicable disease risk in the general population. This was based on a systematic review showing uncertain long-term effects and potential associations with increased risk of type 2 diabetes and cardiometabolic outcomes in observational studies. Conditional means the certainty is low, and individual use may still be appropriate in specific contexts.

What Clinical Trials Show

Randomized controlled trials (RCTs) generally find neutral to small benefits of NSS when they replace sugar, often modest calorie reduction and slight weight loss versus sugar-sweetened options. However, effects can disappear if overall calorie intake doesn’t actually drop.

Why Results Differ

  • RCTs isolate substitutions and control calories.
  • Cohort studies capture long-term habits but can be confounded (people already at higher risk may choose “diet” products).

Practical Takeaways

  • If swapping soda for a zero-cal alternative helps you reduce calories, NSS can be a tool, not a cure-all.
  • Keep overall sweetness down over time; prioritize water, coffee/tea, and whole foods.
  • For diabetes, pregnancy, or GI concerns, discuss personal use with a clinician.
  • Remember: “sugar-free” doesn’t mean “nutrient-dense.”

References:

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