Which one had fewer calories? That's what matters most to most people, barring any special medical conditions. Calories aren't the only thing that matters to weight control, but they're the main thing.
Only if the calories are close would I move on to start deciding between fat and sugar. And at that point, it starts to matter what kind of fat and what kind of sugar. In sour cream, "sugar" probably means lactose, the natural sugar that's always present in milk. If you remove the fat from milk (or cream, or yogurt, etc), then in order to get a full cup or tablespoon or whatever, you get more of whatever else is in that food. Read the ingredients to make sure they didn't add sugar or corn syrup or something to stabilize it, but probably it just has a tiny bit more of carbs and protein because taking out the fat left more room in the cup that had to be filled. If the serving size were larger, you'd probably see that it's higher in protein, calcium, and possibly even some vitamins. If there are no added sugars, then I would use a lower-fat, lower calorie product, because it's not really higher in sugar-- it's just higher in "not-fat."
With some foods, though, a healthy natural fat might be replaced with added sugar. That's what happens with most brands of reduced-fat peanut butter, for example. Peanut oil is one of the healthy fats, so unless you have a health problem that requires you to avoid all kinds of fat, there's no advantage to a low-fat peanut butter. You're losing part of the healty fat that's the reason you eat peanut butter to begin with, while getting extra added sugar that you don't need.
And remember that cookies, cakes, potato chips, etc, are foods that you don't need and shouldn't eat very often, regardless of whether they're reduced fat or reduced sugar. That's why low-fat got a bad name; people saw the recommendation that said "eat less fat" and decided it gave them permission to eat whatever they wanted as long as it wasn't fat. Anybody remember Snackwells cookies? They were "fat free" but had just as many calories as Mallomars, which had something like 1g of fat anyway. But because they were fat free, people chose to believe they could eat a whole box for lunch and it would be "healthy." The same thing is happening now with "low carb." Too many calories are too many calories, regardless of where they come from.
| current weight: 132.0