When they tell you that you can't believe it's not butter, it's a damned lie. Butter is creamy beautiful deliciousness while margarine is mere fake and processed imitation. It's no contest... unless you consider their healthiness. Because we can't have nice things, butter is high in saturated fat. That's no good. However! Margarine, which was made to be healthier than butter, ain't so good itself.
ASAP Science decided to take a closer look at the difference between butter and margarine and determined that though butter is truly high in saturated fat, margarine can be just as bad because of its trans fat content. Margarine is also the wild wild west of pale yellow spreads too, as one version can be hugely different than another because it's so processed. Basically, they're both not exactly healthy. If that's the case, I'm totally siding with butter. [ASAP Science]