Can low/no calorie sweeteners help us lose weight? Your question answered by science

New study reviews the totality of clinical trials on low/no calorie sweeteners effects on body weight


  • A healthy and balanced diet is important for good health as well as for helping manage our body weight.
  • The main finding of a new systematic review and meta-analysis is that replacing sugar with low/no calorie sweeteners may help achieve weight reduction.
  • This effect was particularly evident in people with overweight/obesity and those under an unrestricted “free” diet.
  • No evidence in this study to support the claim that low/no calorie sweeteners consumption may promote weight gain.
  • The authors consider that the study ‘can be used to provide a strong basis for evidence-based public policy decisions’.

The new year has been marked by an unprecedented situation around the world. In these challenging times, the new priority is to protect ourselves and our loved ones from the new coronavirus outbreak and COVID-19 disease, following the guidelines of our national public health authorities. While staying at home, ensuring our safety and wellbeing, from both physical and psychological perspectives, is our new focus.

In these distressing circumstances, many people may have questions about nutrition. Some are also concerned about changes in their dietary habits and the potential impact on body weight control. Staying at home may lead to increased overeating while being less physically active, which, combined, may lead to weight gain. A healthy and balanced diet is important for good health as well as for helping manage our body weight. Eating sensibly, choosing a varied diet from a range of foods and keeping active are all great ways to boost your health.1

One frequent question is the role of sweeteners on body weight. Can low/no calorie sweeteners help in controlling body weight? Or do they hinder this effort? A new study by Hugo Laviada-Molina and colleagues, published in March 2020 in the scientific journal Obesity Reviews2, evaluated the totality of published clinical trials in humans to answer these questions.

A closer look at the study’s results

The study analysed data from 20 published randomised controlled trials and found that the use of low/no calorie sweeteners results in clinically appreciable lower body weight/ body mass index (BMI) values in certain clinical scenarios. The favourable effect of low/no calorie sweeteners was found to be more significant when they are used as a substitute for sugar, especially in the adult population, in people with overweight or obesity, and in those who follow an unrestricted “free” diet. When low/no calorie sweeteners were compared to non-caloric comparators such as water, there was no difference in body weight.

Practically, using low/no calorie sweeteners instead of sugar was found to have a benefit of (on average) -1,3kg weight loss for the total sample, with the number increasing to about -2,5kg for people with overweight/ obesity. This finding does not make low/no calorie sweeteners a “magic bullet” for weight loss, but it confirms that they can be one of many helpful strategies to assist in weight control efforts.

Why is this study important?

This study is a systematic review including meta-analysis. This type of study provides the best quality of evidence because it thoroughly looks for all relevant research, critically assesses each study, synthesises the findings from individual studies in an unbiased manner, and presents a balanced important summary of findings with due consideration of any flaws in the evidence.3

Systematic reviews and meta-analyses of randomised controlled trials (i.e. closely controlled and well-designed human studies) provide higher-quality evidence compared to meta-analyses of observational studies. Laviada-Molina et al. point to the limitations of observational evidence for diet-disease relations, including imprecise intake assessment, residual confounding, and possible reverse causation. That is why it is important to consider the evidence hierarchy, particularly when considering meta-analyses as policy-making instruments, which requires a summary of the best-quality available evidence.

Take-home message

In all, the present systematic review and meta-analysis found no evidence to support the claim that low/no calorie sweeteners’ consumption would promote weight gain. In contrast, the results indicate that replacing sugar with low/no calorie sweeteners leads to weight reduction, an effect that is greater for people with overweight/obesity.

  1. British Dietetic Association (BDA). Healthy Eating: Food Fact Sheet. Available at:
  2. Laviada-Molina H, Molina-Segui F, Pérez-Gaxiola G, et al. Effects of nonnutritive sweeteners on body weight and BMI in diverse clinical contexts: Systematic review and meta-analysis. Obesity Reviews 2020; 1-13.
  3. Gopalakrishnan S, Ganeshkumar P. Systematic Reviews and Meta-analysis: Understanding the Best Evidence in Primary Healthcare. J Family Med Prim Care. 2013 Jan;2(1):9-14. doi: 10.4103/2249-4863.109934.