I weighed myself this morning. But first, I combed my hair.
You might think that combing your hair would increase your weight. This is because a combed barnet (Barnet Fair) is more ordered than uncombed, and therefore has less entropy. Less entropy means you can increase the entropy and thereby generate useful energy, and so combed hair has more potential emergy than uncombed. And e = mc squared; energy is mass.
But, by the second law of thermodynamics, you can't get something for nothing. To comb my hair, I expend energy. So combing my hair actually decreases my weight.
Not by much, of course.
Seventeen stone, four pounds.