This stuck me this morning at the gym, which seems to be a hot spot (gyms in general, not just mine) for sexual selection... working to improve chances of getting selected, displaying selection attributes, doing the actual selecting. And there has been a cluster here of evolution vs creation stuff here lately, so I'm posting this question.

Sexual selection takes resources away from the natural selection process of getting more food and getting eaten by something else less. Granted, some sexual selection attributes could be cross-linked to natural selection: a 12-point buck may have better chance of fending off a predator than some lesser deer. But I don't think anyone has proposed peacock's tail as being good for anything except attracting pea-hens. The point here is that once it started, perhaps at some point in the Cambrian, sexual selection has kept pace with natural selection ever since.

So.

Do we think that any factor not directly related to getting food and not getting eaten, such as, for example, gigantism or longevity, once it starts being a thing to select, just keeps going under the same mathematical rules as natural selection until it puts such a dent in food-getting that the species implodes? This is to say, does biological evolution operate under its rules, randomly, and NOT necessarily with regard to efficiency in getting more food and keeping more offspring alive?

Or, do we think a designer would have included an efficiency-damper in the package?

I know that most people here wouldn't bother with this question because there is no objective basis or reason for hypothesizing a designer. But humor me, please.