Sugar != fat in terms of the content of food. If something has zero fat but 400 calories, then it's still bad for you but in a different way. Either way, it's clearly labeled.
The problem is that people don't know how to interpret the labels. Better education would help with that. Weight watchers, for example, has their points formula which boils down the calories, fat, and fiber values into a single number that is easier to understand. Some food packages even include the WW points number -- but it wouldn't be very accurate or scientific to mandate that sort of thing.
I can't recall any other sources other than that Robert Lustig talk, but from what I've understood you gain more fat by metabolizing sugar than by actually consuming fat.
That does not appear to be true. For instance, here is Walter Willett, chair of the department of nutrition at Harvard School of Public Health:
From many kinds of studies conducted over years, we are quite confident now that a calorie from fat will cause a similar amount of weight gain as a calorie from carbohydrate. There are some interesting questions about whether eating carbohydrate calories versus fat calories will make you eat more calories, but based on what you put into your mouth, it's pretty clear that the source of the calories is really not important.
That article is talking "carbs vs. fat." Lustig is talking "sugar vs. everything else," and the key to the sugar-obesity link isn't in calorie quantities, but in how it affects future appetite and preferences. After drinking a soda, you will eat _more_ on average than someone on an empty stomach, even though you've just downed ~45 grams of sugar. It's the same reason why you can enjoy terrible bar food once you're drunk.
I understand that's the case as well. A lot of low-carb diets, such at Atkins, allow you to eat as much fat as you want and you'll still lose weight. Dietary fat is bad for your cardiovascular system, though.
The food that contains 0% fat doesn't contain any fat. That's actually useful information. If people think that 0% fat foods are automatically good for them, that's an education problem not a labeling problem.
Yes, sugar indeed != fat.
When you do eat sugar - it is your body's first choice for energy. This means that any fat you eat gets stored for later consumption... which will be never cuz most of us eat way too much sugar anyway.
A lot of food says 0% fat, when the ultimate result of all that sugar is essentially fat.