It's possible to gain muscle quickly, but over 7 lbs in one year
is difficult without anabolic suplementation.
        Two things would happen with meat, though.  First, the ketosis
would have an instant effect of drying a person out a bit.  They would
loose their gylogen stores before burning fat.  However, this first thing
would only occure of ketosis was truly achieved.  The second thing is that
beef is an excellent natural source of creatine.  For those of you who
don't know what it is, page through any bodybuilding magazine, 1/2 of the
suplement ads are for creatine.  Creatine will add water to the insides of
muscle cells, making them bigger and in fact stronger.
        I would be suspicious of a muscle gain, but without calipers to
messure the actual body fat %, it cannot be ruled out.