I don't think there is any diet that will help with inclusion body myositis, although there are some recommended diets. They also suggested to increase omega-3 fatty acids in your diet by eating salmon, sardines, herring, black cod, omega-3 fortified eggs, hemp and flax seeds, or take a fish oil supplement. Eat more vegetable protein, especially from beans and soy, and choose fish, cheese, and yogurt more often than you choose animal proteins.