It doesn't. Van Gogh was never an Impressionist. He never showed with them, and if anything, we'd call him a Post-Impressionist... if you're really bent on grouping him under an umbrella term. "The Potato Eaters" is more of a Realist piece. He created it when he first arrived to France, and it's actually quite behind the times (and more like a Courbet might be). Van Gogh espoused a lot of artistic theories when he first came to France, ergo many of his paintings within even a few months look starkly different from one another. He did dapple in "impressionistic brushstrokes", but this certainly isn't it. The Impressionists were concerned with happy, modern life - they would NEVER show a miserable scene like an impoverished family who can only afford potatoes. The Impressionists weren't out to make political statements. This work isn't at all Impressionistic. The looser brushstrokes are, again, reminiscient of Courbet - they are rougher to match the subject matter. The Impressionists, also, painted bright outdoor scenes, because they were interested in the effects of LIGHT. This clearly isn't. Van Gogh was not at all an Impressionist!