I'm about to take up swimming training, 2-3x per week - casually, not competitively. I am wondering what the optimal way to maintain LBM is? I assume it's just adjusting for an increase of calories and management of the joints etc, but I recall back in the day (Old&Grey, Dan, Fausto etc) used to advise against swimming b/c of the energy expenditure required - is it actually that relevant beyond adjusting intake?