Real sugar isn't as bad as some of the alternatives. What I really worry about is a substance called "high fructose corn syrup". This can go by the name "corn sugar"--it's the same stuff. Crystalline fructose is as bad. High fructose corn syrup makes you fat, bypasses the hunger mechanism, and is often contaminated with heavy metals like mercury. This stuff is bad for the liver, which has trouble metabolizing it. Regular sugar isn't nearly as bad.
Even worse are the artificial sweeteners. Aspartame and its cousin Neotame (which isn't even listed on the labels) are the worst. These poisons will ruin your brain, often giving you seizures, headaches, and can lead to Alzheimers. Monosodium glutamate is a cousin of aspartame and does the same thing. Sucralose and acesulfame K both harm your liver. If you have to use artificial sweeteners, saccharin appears the safest. Stevia is even better. If you use xylitol, that is as good--just don't let your dog get any.
Here in the United Tyranny of Stupidity (formerly, the United States of America), high fructose corn syrup is common. Virtually everything processed has it--even tomato soup. It is common in soft drinks, juice drinks, many candies, ketchup, pickles, stuffing, many pancake syrups, cookies and crackers, many "healthy(??)" cereals, spaghetti sauces, and numerous dessert mixes. I believe it is very common in most countries--those of you in New Zealand, I have heard, will have a much harder time finding high fructose corn syrup in your food than elsewhere. And, with the backlash against high fructose corn syrup, I predict "corn sugar" will be the next big additive--"No high fructose corn syrup" on the front in big letters, "corn sugar" in the ingredients in the back.