ALS is one test which is specific and is eliminated early in the diagnostic process.
Caffeine, if it triggers a symptom, would not be good. I drink diet Dr. Pepper for one of my MS headaches. It only works for a very specific area of pain and has been 100% effective for me. I tried different caffeine drinks, and for me, they did not work as well.
I have dark chocolate which I consume for yet another area of head pain. Again, this has been 100% effective and only works for specific pain.
Exercise is important as long as it is low impact and in moderation. Aquatic exercise, yoga tai-chi, and modified Pilates are all good choices as is walking. You should also incorporate plenty of stretching. The stretching is a daily regiment 2-3 times if needed (or more). The stretching helps with muscle memory. Should you ever need to use a power chair, you still need to stretch to prevent atrophy. Gardening, yard work, household chores....all these should be factored into your need for exercise.
Moderation is important because when you over do physical exercise/activities, you can cause problems or cause symptoms to present. Also, for me, if I push past a redline it requires a longer period of recovery. During the recovery, keep stretching! Your own sense of moderation can vary. You learn where or what your redline is. My neuro put me on a passive exercise bike. On some days 45 minutes is fine but on other days 10 minutes is all I can do. I watch for the slight signs that my redline is near and I stop before I get there.
If you keep a journal of your symptoms, you might discover what your MS triggers are. The majority of triggers for me are avoidable. If I avoid the trigger, I have a better day. There are also triggers such as seasonal triggers which I cannot avoid unless I win the lottery and can fly south to avoid them!
After 35 years, I can say that there are more good days than bad. Also, re-setting your benchmark as to what "normal" is to you is important. I live with MS problems 24/7, but my own sense of normal keeps me balanced. I do not grieve that which I can no longer do. Sometimes you can make modifications with adaptive equipment or you can learn a new hobby. Do not grieve what you had, but do what you can. I look forward to shedding this broken, corruptible vessel some day.