Organic food has much to recommend it. First and foremost, if you eat organic food you are not ingesting all the chemicals that are routinely sprayed on conventionally grown food. It doesn't do anybody any good to be consuming petrochemical derivatives, much less people who have chemical sensitivities, as so many people with CFS/ME do. For people with CFS/ME it makes inherent sense to avoid putting harmful chemicals in our bodies. We are already struggling with an illness. Why add to the burden? From other standpoints – the geophysical ramifications of continued spraying of pesticides and herbicides – it is also a good idea to eat organic. In short, it can help you to eat organic, and it certainly won't harm you.
A second point to remember is that even organic food contains petrochemical and inorganic contaminants. The heavy metals that the soil has accumulated after decades of farming techniques that used arsenic and lead are all still there. (The only way to get rid of them is to remove the soil.) There are pollutants in the air that get washed into the soil with every rainstorm. And, of course, there are the breakdown products of chemicals that may have been previously used. Even strictly organic food contains the legacy of many years of conventional farming.
Personally, I prefer organic to conventional produce. It hasmore flavor. There is simply no comparison between one of those round, red things your supermarket calls a tomato and what comes out of an organic garden. Green beans, broccoli, potatoes and carrots - especially carrots - all taste sweeter, fresher ... more vegetal. There is no doubt that pesticide-free food is better for you and better for the planet, but beware of practitioners who proclaim that a change of diet will cure you.
The reason organic food won't cure you is that eating conventionally grown food is not how you got sick. True, some people become ill after being exposed to pesticides, but in those cases the exposure was direct. Even if you remove the pesticide residues on your food, you will still have to deal with the actual cause of the illness.