No, it’s not the latest fad diet: Marketing Pilgrim. Marketing news, folks. How many of us have stared at the thousands of spam messages and wondered, “Why on earth do they keep sending this crap out? It can’t possibly be effective . . . can it?”

Unfortunately, incredibly, in some industries, the answer is yes. As MediaPost reports, a small study showed that even recipients without weight issues opened and purchased from spam weight loss emails, as published in the Southern Medical Journal this month.

Though the sample size was only 200 (and probably not representative—students at a single New York commuter college), the findings are startling: 18% of those without weight issues opened the spam emails and 5% actually purchased. Of those who identified themselves as having weight issues, 40% opened the spam and 18% purchased.

MediaPost clarifies that these numbers aren’t necessarily great on their own: “The study does note that the purchasing behavior is at a lesser level than a six-country survey for any health or pharmaceutical product.” However, the fact that even those outside the target audience opened and bought from a spam email is pretty significant.

MediaPost also notes that the emails appeal to a “captive, maybe even desperate audience” (and if you’ve ever really battled your weight, you know that feeling), so these findings probably won’t apply across the board. And given that one out of twenty non-target audience members also purchased, suddenly I’ve lost hope that those dozen daily Viagra ads will go away.

What do you think? Is the study skewed? Or is spam really that effective (for some products)?