Meditation is a powerful tool that I have used consistently and effectively for 16 years. The monk that got me hooked had a good point: "If you're scientific, you'l conduct an experiment. The experiment is meditation. If it works, it will make you happier. And if you're happier, why would you stop?"
I never did. Since that talk, I meditate twice daily and have maintained that pattern for over ten years, no matter what happens in my life. Once when I get up and once before I go to bed.
I do it right away when I get up because the day gets crowded really fast, and then right before bed as helps me end the day with a clear mind and relaxes me.
How much does the research show you need to do to start seeing changes? Six different studies used 90 minutes a week, which breaks down to 7 minutes twice a day. Set a timer, close your eyes, take a few deep breaths to relax and just breathe naturally. This amount has been shown to decrease anxiety and improve mood.
What powerful unforeseen changes will happen to you?
There are plenty of subjective studies which have shown improvement in mood, decreased anxiety, decreased emotionality, and improvement in cancer rates, when combined with diet, exercise and therapy.
But these things are hard to really believe if you're a skeptic, as it's hard to really "see" these results, unless you're the person experiencing them. And maybe it's you just convincing yourself, right?
The best evidence I think for skeptics are the MRI and functional MRI studies into long time meditators. (I've included a link to a great summary study here and here.) MRI can be used to see the contrasting development of brain areas, by size differentials in actual brain mass and by the folds of the grey matter, which is where brain function occurs (the more folds, the more function). Functional MRI or fMRI looks at the activity of the brain by measuring how much oxygen is being used by a particular part. You can compare a "meditation mind" to a nonmeditator's brain and see where oxygen is being used differently.
If meditation did nothing different in the brain, a skeptic might be right- maybe it's all placebo effect. There's no real benefit to meditation.
But what we see in reality are distinct changes. Things you will see on the MRI and fMRI in long time meditators are in two main areas:
an increase in brain size and function in the hippocampus, which is involved in emotional processing and a decrease in activity in the DMN, the default mode network, a group of approximately 9 areas in the brain which are involved in "mind wandering" and absent thought.
What does that mean in translation?
The bigger hippocampus helps us have more bandwidth to handle more emotion in a calm manner without getting overly stressed. The lowered DMN activity gives us a less busy mind.
So meditation leads to a calmer approach to thinking, and a clearer mind in which to live life.
You probably will never get an fMRI study done, but once you start, you may find, like me, that you won't want to stop!