Toppings cause 50–200% portion errors (Almiron-Roig et al., Appetite 2013). Per 100 g: 74 kcal, 0 g fat, 3.1 g protein. A dollop of sour cream is about 30 g — easy to double without noticing.
How should I track Sour cream, fat free?
The best way to track Sour cream, fat free is by weight, not volume. A 200 g serving of yogurt or cheese varies in density between brands and fat levels, so the same portion can differ by 20–40 calories. Research shows people underestimate calorie-dense dairy portions by up to 50% when eyeballing (Almiron-Roig et al., Appetite 2013). A kitchen scale keeps things honest. Also check whether the label lists values for the product as sold or as prepared — some powdered or concentrated dairy products show very different numbers once mixed.
