Abstract
Numerous strategies have been investigated to overcome the excessive weight gain that accompanies a chronic positive energy balance. Most approaches focus on a reduction of energy intake and the improvement of lifestyle habits. The use of high intensity artificial sweeteners, also known as non-caloric sweeteners (NCS), as sugar substitutes in foods and beverages, is rapidly developing. NCS are commonly defined as molecules with a sweetness profile of 30 times higher or more that of sucrose, scarcely contributing to the individual’s net energy intake as they are hardly metabolized. The purpose of this review is first, to assess the impact of NCS on eating behaviour, including subjective appetite, food intake, food reward and sensory stimulation; and secondly, to assess the metabolic impact of NCS on body weight regulation, glucose homeostasis and gut health. The evidence reviewed suggests that while some sweeteners have the potential to increase subjective appetite, these effects do not translate in changes in food intake. This is supported by a large body of empirical evidence advocating that the use of NCS facilitates weight management when used alongside other weight management strategies. On the other hand, although NCS are very unlikely to impair insulin metabolism and glycaemic control, some studies suggest that NCS could have putatively undesirable effects, through various indirect mechanisms, on body weight, glycemia, adipogenesis and the gut microbiota; however there is insufficient evidence to determine the degree of such effects. Overall, the available data suggests that NCS can be used to facilitate a reduction in dietary energy content without significant negative effects on food intake behaviour or body metabolism, which would support their potential role in the prevention of obesity as a complementary strategy to other weight management approaches. More research is needed to determine the impact of NCS on metabolic health, in particular gut microbiota.
Summary
In line with a series of systematic reviews of clinical studies, the conclusions of the current review support the assertion that low/no calorie sweeteners can be used to facilitate a reduction in calorie content without significant negative effects on food intake behaviour or body metabolism. This, in turn, supports the potential role of lo/no calorie sweeteners in the prevention of obesity as one among a pool of weight management strategies.
The authors state that while some evidence suggests that some sweeteners have shown the potential to increase subjective appetite, these effects do not translate in changes in food intake. The lack of effect is also shown by a large body of empirical evidence advocating that the use of low/no calorie sweeteners facilitates weight management when used to replace sugars and alongside other weight management strategies. Overall, meta-analysed evidence points towards a modest reduction in body weight following low/no calorie sweetener consumption, compared to increases in body weight following a sucrose-sweetened diet. In addition, this reduction in body weight was more pronounced particularly in participants with overweight and obesity, rather than healthy weight individuals.
Regarding their impact on glucose control, evidence reviewed in this paper supports the assertion that low/no calorie sweeteners do not affect total insulin levels and do not stimulate insulin secretion to the same extent as natural sugars. While the authors note that sweeteners are very unlikely to impair insulin metabolism and glycaemic control, they discuss some studies which suggest that sweeteners could have putatively undesirable effects through various indirect mechanisms on body weight, glycemia, adipogenesis and the gut microbiota. However, the authors add that there is insufficient evidence to determine the degree of such effects as human evidence for non-caloric sweetener-induced alterations in microbiota is scarce. Some recently published clinical studies has shown no effect of low/no calorie sweetener consumption on gut microbiota composition and diversity (Thomson et al, 2019; Ahmad et al, 2020). O’Connor et al conclude that whether low/no calorie sweeteners perturbate the microbiota composition and whether the resulted dysbiosis increases short-chain fatty acids (SCFA) production in larger populations remains to be determined. In addition, the role of energy harvest in human energy balance is of uncertain significance, whilst SCFA have been associated with overall positive health effects in human studies.
