Prettykin diet
The infamous super-restrictive food-choice regimen that supposedly increases the chance that (1) your currently-existing relatives ("kin") will seem better-looking to you than they did before, and (2) you'll produce more attractive offspring than you might have with just a "regular" diet.
The Prettykin Diet is of questionable value at best, especially considering that (A) you'll likely feel ravenously hungry all the time, (B) it often produces horrendous flatulence, and (C) the diet's original founder committed suicide (or maybe he just succumbed to sheer hunger??).