If you get tired, anxious, and have a headache when taking animal bone broth, you could have a histamine intolerance, and in that case a vegetable and green juice fast with lightly steamed vegetables would be better for you. You can melt 1 Tbsp. of coconut oil over the vegetables twice daily. For the general fast, 12-16 oz. of bone broth (can be beef or chicken or a mixture of both, see what your body tolerates) and 1 tsp. of coconut oil (optional 1-2 Tbsp. of collagen to keep your protein up and to heal leaky gut faster). If you get tired, anxious, and have a headache when you take bone broth and know you do not have a histamine intolerance, do not do the fast yet. Instead start out with 1 c. daily until the headaches go away and then move into the fast when it feels appropriate. This can be a symptom of detoxing and doing a bath or a foot soak with magnesium oil is highly suggested.