I have lost half a stone the last 6 weeks through walking and improving my diet

But I do wonder about the advice given , especially in the men's health type magazines ?

How much are age and genetics a factor indeed are they the main factor ?

What do these experts mean by some people being hard gainers ?

I don't want to waste my time weight training at my age if it's a trivial pastime and I would be better off doing some yoga or pilates ?