Even though mercury detox is very important, it's best to leave it for later, when you are feeling already good and healthy. It can get really tough once you start to mobilize heavy metals throughout your body in order to eliminate them. As a general rule, it is best to eat healthy for a while, eliminate food sensitivities, healing your gut and taking some nutritional supplementation (vitamins C, B, magnesium, probiotics, digestive enzymes, multivitamins/minerals). That alone will make you stronger and may diminish significantly your crave for drugs. It would definitely diminish the crave for unhealthy foods because we often crave what is bad for us, but once that is cleared from the body our will strengthens and it becomes easier and actually desirable to stay away from the bad foods.
The stimulation of the vagus nerve through the pipe breathing part of Éiriu Eolas helps particularly to decrease drug and food cravings by helping to balance your brain chemistry and your brain as a whole.
There are nutritional rehab programs to recover from drug addictions, basically balancing the brain chemistry with proper detoxification and nutritional supplements in order to make it easier. Often, drugs are relievers of real biochemical mood problems. Supplements consist basically of certain amino acids that are lacking and that makes you crave certain drugs. The Mood Cure by Julia Ross has very good protocols and I really think you should read it so you can understand yourself and your brain chemistry better. She has also a good record in helping people to recover from their drug addictions with natural rehabilitation programs consisting of certain amino acids. Her dietary suggestions are good, but it falls short in other points. Eliminating all dairy products and cereals because of the issue of casein, gluten and lectins is really a priority. Also processed foods, hydrogenated vegetable oils, evil additives like aspartame and MSG. You can use lard to cook. You can get some pretty good recipes in the health section of the forum, they are very delicious. All gluten recipes and foods can be replaced with buckwheat, quinoa or amaranth. You can also have wild rice.