Could it be this?
http://en.wikipedia.org/wiki/Fasciculation#TreatmentQuote:
Inadequate magnesium intake can cause fasciculations, especially after a magnesium loss due to severe diarrhea. Over-exertion is another risk factor for magnesium loss. As 70-80% of the adult population does not consume the recommended daily amount of magnesium,[4] inadequate intake may also be a common cause. Treatment consists of increased intake of magnesium from dietary sources such as nuts (especially almonds) and bananas. Magnesium supplements may also be taken. However, too much magnesium may cause diarrhea, resulting in dehydration and nutrient loss (including magnesium itself, leading to a net loss, rather than a gain). Chelated magnesium can help reduce this effect.
Fasciculation also often occurs during a rest period after sustained stress, such as that brought on by unconsciously tense muscles. Reducing stress and anxiety is therefore another useful treatment.[citation needed]
There is no proven treatment for fasciculations in people with ALS. Among patients with ALS, fasciculation frequency is not associated with the duration of ALS and is independent of the degree of limb weakness and limb atrophy. No prediction of ALS disease duration can be made based on fasciculation frequency alone.[5]I get it sometimes, I find it quite amusing. Feels like someone is poking me in the back with a finger.