I don't agree with the idea that its not the foods that will heal but a lack of bad foods that will heal the body. I think foods have amazing healing properties and not just fruits but also vegetables and many herbs. The only problem that comes in, is when our digestion becomes impaired, then all food becomes toxic and unfortunately digestion cannot always be repaired by fasting and fruitarian diets. I always think about all of this in terms of ayurveda because that is what has helped me to understand how the energy of our body functions. Long-fasts and following raw diets, will greatly increase the amount of cold energy in the body, some people will have great success on these because it suits their body perfectly. As you said, eating fruitarian in the winter in a cold climate is difficult because it is a cooling diet. For people like me (never did fruitarian, but I have done raw diet, lots of juice fasting and water fasting) increasing this cold energy when I already had a lot of this type of energy to start actually greatly impaired my digestion to where I had more and more food intolerances and basically couldn't eat anything. Finally, I realized all of this was not working for me and ayurveda has greatly helped me to repair some of the damage I have done.