I personaly, have never felt quite right after consuming sweet foods and even less so after a soft drink As it turns out, Liam Mannix from The Age and researchers have been looking at this situation and have done some pretty fancy blood monitoring. The resulting research clearly graphs the levels of the hormone Insulin which, post a single can of softdrink as a regular habit can clearly put you on a path to diabetes.
A single can, at say morning tea, clearly and sustainably raises your insulin that would otherwise return to much lower levels post breakfast meal and a second can, in the afternoon tea does the same for the insulin peak from lunch meal i.e. not allowing the blood insulin level to return to background low levels over a whole day. For one thing you will not lose any fat, worse, you will store more of it.. read on.
Insulin is a natural hormone with at least a couple of basic functions. The first is, it is a response to an elevated glucose (blood sugar) level to begin removing and storing it ....as fat (long term energy storage). Secondly but much more importantly, it is a messaging system for the body's various organs and systems. You can think of it as an internet albeit a chemical and blood based one.
A sustained high level and over a wide period and it becomes like that loud person at the office. It becomes background noise and later, we learn to ignore it. It it continues much longer, we even tune out the shouting. The trouble being that some of that shouting is critical information. It's like a car that begins to ignore the driver. You can see where this is going to end up sooner than later.
It's a fascinating read: The Age article
How does all this work again? Ok watch this:
And this video goes a great job of explaining the sugar to the types of blood sugar stores and the role of potassium.
From a Chinese Medicine point of view, sweet foods affect the digestion side of the 5 elements (spleen/stomach) in very very low levels like from a pumpkin it is thought to be a beneficial tonic. The effect being grounding, but, as the Five Element theory goes, once extremes are encountered it transforms into the opposite action. In this case from tonifying or strengthening it disrupts. Here, it disrupts and scatters the earth element (spleen/stomach) Qi which then often overcontrols the water element where hormone fuctioning is thought to reside.
To you, this disruption and scattering of the earth element often feels like an initial boost and then that "ugly as sin" afternoon looooow. That afternoon lul where you can barely hold up the eyelids. Please someone pass me a stimulant. As you can see, this can result in a feedback cycle of the dangerous kind.