Increasing evidence suggest that artificial sweeteners such as saccharin, aspartame and sucralose may not be as metabolically safe as they first appeared, and it has been proposed that their consumption may be linked to important disturbances in the gut microbiome. Some in vitro and in vivo studies suggest that the recently approved sugar substitute Stevia (eg. steviol glycosides) can also influence intestinal homeostasis. However, it is not clear whether this natural non-nutritive sweetener (NNS) could also cause metabolic and microbiome disturbances as proposed for their synthetic counterparts. In fact, steviol glycosides may even have a beneficial impact on glucose homeostasis and lipid metabolism possibly through a positive action on intestinal health and gut microbiome, but this has yet to be experimentally tested in a rigorous study.

The main objective of this project is to evaluate whether steviol glycosides sweetened beverages (SGSB) or aspartame/acesulfame K sweetened beverages (AASB) exert beneficial, neutral or detrimental effects on metabolic health of regular consumers of sugar-sweetened beverages (SSBs), and whether modulation of the gut microbiome is involved in the resulting impact of these NNSs on metabolic health.

As chronic overconsumption of SSBs is clearly associated with an increased cardiometabolic risk, this study will be the first to determine the metabolic impact of replacing SSBs by potentially "healthier alternatives" such as the increasingly popular stevia-based soft drinks and aspartame-based soft drinks. The investigators will further investigate whether these NNS can cause pernicious effects on intestinal health and the gut microbiome. It is a crucial concern since the importance of this unsuspected key "organ" has been ignored for too long and its important implication in many chronic societal diseases has just been discovered.

Results of this study could have a direct influence on health, nutrition and even agricultural policies as well as dietary guidelines around the world. This project is also critically important as an increasing amount of health professionals such as physicians, nurses and registered dietitians seek to provide evidenced-based guidance to individuals looking for healthier alternatives to SSBs including stevia-based or aspartame-based soft drinks.

Inclusion Criteria:

• Men and women in good health
• Soft drinks consumers (between 4 cans/week to 4 cans/day)

Exclusion Criteria:

• Metabolic disorders (hypertension, diabetes, hypercholesterolemia)
• Daily consumption of more than 4 cans of soft drinks
• Regular use of medication affecting study parameters
• Change of medication (type or dose) in the last year
• Use of antibiotics in the last 3 months
• Change in natural health product use in the last 3 months
• More than 2 alcohol drinks par day
• Weight change of more than 5% in the last 3 months
• Surgery in the last 3 months or planed during the study
• Allergy or intolerance for products contained in soft drinks