When you consume a fizzy drink your body quickly absorbs the fibre-less sugars, the glucose spikes your blood sugar, which stimulates insulin and subsequently signals to your body to store body fat, inflammation is increased, triglycerides are raised (essentially fat in your blood), and Leptin, one of the hormones involved in appetite regulation, is blocked. Leptin is responsible for signaling to your brain that you’re full, if the brain doesn’t get told it’s full you continue to eat and often on low fat, high carbohydrate diets experience the feeling of “never being full.”