It can be interesting to see how a link in the chain can be passed over, that there have been many studies about fizzy drinks and obesity but not about how appetite changes play a role between the two.
"Sugar-sweetened soft drinks have been linked with obesity but few studies have examined how the energy content of soft drinks could impact on appetite.
In a crossover study, Danish scientists gave 500ml drinks to 24 obese subjects. These differed in terms of energy content, i.e. 1) regular cola 215 kcal; 2) semi-skimmed milk 227 kcal; 3) diet cola 1.8 kcal; or 4) water 0 kcal. Appetite scores and hormones levels were measured at baseline and after 4 hours. Participants were then allowed to eat as much as they liked at a meal.
Interestingly, drinking milk led to significantly greater feelings of fullness and less hunger than drinking regular cola. Changes in appetite hormones, e.g. ghrelin, were 20% lower after drinking milk/cola compared with water, but energy intakes at the test meal were also higher after either of these beverages. These findings suggest that calories in beverages, both milk and sweetened soft drinks, have a minimal impact on appetite and do not appear to inhibit food intake at a later meal."
For more information see: Maersk M et al (2011) European Journal of Clinical Nutrition Vol. 66: pg523-9.