## 4 Discussion  
The results of this trial suggest that compounds present in sugarcane possess anti-obesity properties. Due to the negative attention that sugar has received as a factor in the development of obesity, these may be considered surprising findings [20]. However, there is growing scientific evidence indicating a potential ability of other compounds present in sugarcane, such as polyphenols, that may assist in the metabolism of sugars [17; 21; 22]. It was hypothesized that the effects these compounds have on metabolic pathways may have implications for obesity and weight control. However, this study is the first report of weight loss in an animal model to be correlated with the presence of sugarcane-derived polyphenols. Furthermore, the data collected in this trial provides useful insight into the potential mechanisms driving the observed anti-obesity effects. The weight reduction does not appear to be mediated by a reduction in food intake. Based on food intake there were no significant differences between the control and PRSE treatments. This is an important finding, as it suggests that the reduction in body weight is not due to a difference in food palatability or increased sensations of satiety that result in a simple reduction in calorie intake. There were significant differences in water intake over the course of the trial and it is difficult to hypothesize what may have caused this result. Other studies into the effect of natural products that reported decreases in body weight using rodent obesity models  
Figure 6: Analysis of expression levels of genes associated with lipogenesis/lipolysis in mice with diets supplemented with PRSE. Following the trial mRNA was isolated, RT-PCR performed and products quantified from mice in the control group (black bars) and in the groups with a diet supplemented with 2% (light bars) or 4% PRSE (dark bars). Adipose tissue gene expression analysed included (**A**) adiponectin mRNA, (**B**) PPARy, (**C**) Uncoupling Protein 2 and (**D**) Fatty Acid Synthase. Liver gene expression was analysed for (**E**) PPAR\({}_{\alpha}\), (**F**) PGC1\({}_{\alpha}\), (**G**) Uncoupling Protein 2 and (**H**) Fatty Acid Synthase. Data are expressed as mean (\(\pm\)SEM) fold change in mRNA levels. Graphs with different superscripts (a, b, c, etc.) differ significantly \(p<0.05\). have reported either no change to water intake [23] or reduction [24]. It therefore appears that the increased water intake observed in this trial is not required for anti-obesity effects across all plant extracts. It may however be an indicator of a secondary benefit not targeted in this trial. For example, a study on ginger polyphenols showed an improvement in rat kidney function correlated with increased water intake [25]. These same conclusions cannot be made from the data in the present study into sugarcane polyphenols, but further work into this area may be justified. The anti-obesity effects of PRSE do not appear to be mediated by changes to the metabolic rate or an increase in activity. One of the mechanisms of the weight loss appears to be an interference with nutrient absorption or feed digestibility. This is observed clearly in the increased excretion of energy and carbon in the faeces and reduced digestibility of feed. The increased energy in the faeces is an indicator that more carbohydrates are being stored in the body of mice fed the control diet. There is in vitro evidence that phenolics extracted from sugarcane are capable of inhibiting enzymes in carbohydrate metabolism such as \(\alpha\)-glucosidase and \(\alpha\)-amylase [26; 27]. Previously, we have demonstrated that PRSE is able to inhibit glucose and fructose uptake in cell culture conditions also [17]. However, the data shown in the present study of the shift in faecal carbon content is the strongest evidence to date that these sugarcane-derived compounds have a direct action on carbohydrate metabolism in vivo and that one aspect of the weight loss effect may be attributed to the inhibition of carbohydrate uptake.