I never told the world this, but I started eating low-carb after reading Good Calories, Bad Calories by Gary Taubes. He made a very compelling argument backed up by lots of research (some of it very old) showing that it's not just the "calories in, calories out" formula but triggers in our body that cause us to gain weight. He blames carbohydrates as the primary culprits for weight gain and explains the insulin cycle very well.
His short summary was that carbohydrates spike blood sugar which caused the body to release insulin, insulin causes the body's cells to absorb blood sugars and convert them to fat, therefore eating carbs is why we're fat. He also directly attacks the calories in, calories out theory citing studies showing people that are thinner eating the same amount as their thicker counterparts even in the presence of exercise and even goes on to show evidence that if you cut calories, more often than not your metabolic rate slows, the body doesn't usually use fat. I think there's exceptions to this rule when there's people that are food addicts, but for most people who have a little extra around the waist, I think this is true.
Gary then moves on to attack the notion that high blood cholesterol is caused by eating too much cholesterol. He shows examples from President Eisenhower's struggle to combat high cholesterol as evidence of the fallacy that eating too much cholesterol causes high cholesterol levels, but that they are actually caused by a high % body fat in most people (I have a cousin who has metabolic problems, so she actually does have to watch her blood cholesterol). But for normal people, Gary is right, the body absorbs cholesterol with respect to its % body fat and even creates it if the levels don't match what they should be according to your % body fat. Long story short: Lose fat if you want to lower cholesterol.
Anyway, long story short I read Gary's book just after gaining about 6% body fat. I was also eating pasta for dinner at the time I didn't eat more than 700-1000 calories and usually had less at another time of the day to make up for it and I would swim a lot too. Later, I went on to take Gary's suggestion and initially I lost about 4.5% body fat. But then after that initial loss, I started feeling really weird. Like I would be satiated (my stomach would feel fine, etc) but my body would feel starved. I ended up eating carbs on and off in order to feel better, but was still scared of them (for the most part, if I lost wieght, I'd eat more in a heartbeat).
Then I decided to do some research a few days ago that helped me understand carbohydrates better. First, you can spike your insulin levels with proteins and fats, it's just harder to. Glucose spikes insulin levels easier than proteins and fat. There are also things you can do to prevent carbohydrates from spiking your insulin levels. Eating protein and fiber with carbohydrates slows the rate of their absorption into the bloodstream. Also, most carbohydrates convert to glucose after being processed. Apparently it takes more effort for the body to store glucose as fat than fat or fructose. Fructose is wierd, it acts kind of like a fat with respect to insulin regulation, but is actually a carb. This article talks a little about this and shows how high fructose corn syrup has been linked to more weight problems here in the US.
Basically, I think Gary Taubes was right on a lot of fronts, but his demonization of carbohydrates is unnecessary. I've been feeling better since I started eating more carbs (but wisely) and think that there's a good plug to be put in for both exercise and blood sugar control.