For deontological reasons, I've been vegetarian for about a year and a half. I recently decided to make up inaccurate numbers to see if the decision makes sense on utilitarian grounds. The sources I trust seem to agree that eating meat will improve my health*, so on one side of the equation I had [extra lifespan] * [expected earnings per time] * [fraction of earnings I currently donate] * [lives saved per dollar donated]. On the other side of the equation, [expected years of life] * [amount of meat an average American eats per year] / [usable meat per animal].

Conclusion: I don't care about animals that much, compared to humans. The result was two orders of magnitude away from even being a difficult decision, so even my horrible made-up numbers were persuasive. I've been eating meat for a couple of weeks, now.

I was publicly vegetarian for a while, so I was afraid of telling people; it felt like admitting I'd been wrong. Nothing embarrassing happened. I'll remember this next time I fear looking foolish for changing my mind.