I haven't reviewd this in a while. Take it with a grain of salt. Or sugar, hehe.
The digestive track: Mouth Esophogus Stomach Small intestine Large intestine
Nothing too new there, except for omissions due to my own ignorance, or enough ignorance to assume that the above may have omissions.
After the acid bath and pancreatic activity in the stomach, your food contents pass through the small intestine. The small intestine is for absorbing simple and fairly simple sugars. Glucose and fructose are mono-sacharides. The two together as sucrose is a disacharide. Those are supposed to be digested here in the small intestine. Or not really digested all that much, but mainly absorbed.
Free glucose is easily absorbed and countered by insulin in healthy subjects. Blood sugar regulation is strongly linked to metabolism. Hypo-glycemia is not far from hyper-glycemia, and is also related to tonicity of the blood, which is related to water, sugar, and mineral intake, and the bodies alterations of such. The glucose can also be uptaken as glycogen for longer term storage versus the immediate glucose supply in the blood. Fructose is only assimilated by two receptors, often problematic in certain peoples, I believe such as myself. There is a fructose only receptor, the most common in lack. And a glucose-fructose receptor. If the fructose-only receptor is not plenty enough to claim the fructose before it hits the large intestine... I'll get to that later. But anyways, the small intestine is for the simple sugars. The large intestine is for the bigger stuff. The large intestine is like a big fermentation sewer. The small intestine is for rapid assimilation and keeping some bad things out of the large intestine.
The metabolism of fructose after the receptors in the small intestine involve the liver, and generally the process is not as nice as glucose. Not to say fructose is bad, just to be slightly more leary of it.
Lactose is similar. It digests into a gluco-something and glucose. The gluco-something has a slightly more involved process for assimilation than glucose. If lactase is not present or secreted adequately, it makes its way into the large intestine.
Sugar/sucrose is not exactly glucose-fructose to the small intestine. An enzyme called sucrase is used to break it down and then be processed by the receptors.
If these simple sugars make it into the large intestine, they are feasted on by bacteria. Generally, the bacteria that digest simple things are not the ones you want as much. They can produce alcohols, methane, lots of hydrogen, and other gasses as they eat the fructose, lactose, and other simple sugars not taken up by the small intestine. These gasses cause pressure to build up in the large intestine. Like any mostly sealed container capable of stretching, it stretches from the extra pressure of the gasses unless they are let to escape instantly. Solid mass fills the larger space and stools get larger in diameter. Once the gas is gone, the solid mass holds them to a similar diameter as before.
Beyoond the bloating, this causes other problems. Typtophan uptake can be hindred, which affects serotonin levels, which can potentially cause forms of depression. You can also distinctly smell something wrong with the stools, unless it is masked with activated charcoal or something similar. Fermented lactose smells a bit like rotten milk.
Anyways, these are my thoughts and personal experience. The above may not be correct at all. But if you ever feel depressed for no real reason, this could be related. I experience it quite a bit over lactose, and maybe fructose, but I don't think so. If you are lactose intolerant, you may want to avoid milk and yogurt. You can try different types of yogurt to see if one works or not. The more sour and less sugars listed on the nutrition label shows greater or reduced lactose amounts. Activated charcoal should help, but does not do a lot for the bloating, I think due to the quantity taken versus gasses produced from the lactose.
In general though, in theory, sugar should not cause bloating if it is properly absorbed in the small intestine, period. Sugar really isn't that bad, it's just your body that can make it bad. Same goes for milk/lactose. The candida crowd may have the slightest bit of merit if they are also fructose/lactose malabsorbant. The bacteria in your large intestine will tailor themselves to the inputted substances over time. Your alfa sprout sandwich with agave nectar fries becomes fructose for whatever bacteria are in your large intestine. Mild quantities of this aren't bad, but the long term effects of it are not usually good.
Health is a holistic thing where the entire balance of the body can come down to one receptor type, a quantity of enzymes, and even the position of your stomach relative to your diaphram. And there's a ridiculous amount of nerve endings going into your large intestine. Every thought and feeling you have has some correlation to the enzymatic reactions and bacterial action in your intestines. It generally works silently, but is always amazing.