Sweetener found in soft drinks, flavoured water and concentrated drops to dilute are real enemies to people who wan't to lose weight. Natural sweetener or synthetic are substances which have a large sweetening power. So, a small quantity gives a lot of flavours. Since quantities are infinitesimal, these molecules have the advantage of not giving calories. All sugar's taste, without calories! This is the secret of these substances. So why should we ban these products if we wan't to lose weight? With observation studies, we see that people which eat these kind of foods has "rage" of "cravings" insatiable for sweet foods. Unable to resist, they eat sweet foods in too much large quantity. They end by taking more weight instead of losing it.
Why is the temptation more present with consumers of "false sugar"? Because soft drinks with "zero calories" offers sugar taste without producing it's effect in the body.
True sugar, when eaten, raise glucose and favorise secretion of insulin. Insulin allows sugar in bady cells. This hormone has another function, to favorise entry of amino acids inside tissue. But the tryptophan, an amino acid, which resist to this effect. So when eating sweet food, blood becames more concentrated with tryptophan. Therefore, a larger quantity of tryptophan will get to the brain. When it gets there, tryptophan favorise productions of serotonin, a neurtransmitter which has a known effect of "calming". So, when foods taste like sugar without having sugars, they don't produce this calming effect that leads to pleasure of eating. It's how we became insatiables, since we always try to satisfy fully this need.