Fasting (and other important related things)
I recommend filling your nutritional reserves and reading up on all possible complications before attempting a fast. Nutritional reserves should also include enough fat to fuel your body's energy needs throughout the duration of your fast (it can also use this fat to make water if dry fasting). If you're new to fasting it is highly recommended that you start out slowly to allow your body to adapt. Try intermittent fasting or restricted eating windows first. Being keto adapted (low carb/ketogenic diet) will reduce negative symptoms and spare more muscle during the fast.
I think it's also important to note that while there are many science-backed benefits of fasting, there is a lot of pseudoscientific bunk or mythology surrounding it. Careful research with a keen skeptical eye should be done to gain a better, more factual understanding as well as an awareness of the risks and necessary precautions.
One thing I often see is the belief that all symptoms are just detox and that you should just ride them out. While there may be some toxins released from fat there are also other (possibly more likely) causes. A few are dehydration, electrolyte imbalance, or low blood pressure. Not every symptom is detox/cleansing. While some symptoms can be expected while fasting (especially if you're just starting out), it may be wise to stop if they become too uncomfortable or severe.
If you're water fasting, making sure you're getting some electrolytes (sodium and potassium most importantly) will enhance your experience and make your fast much safer, allowing you to get through it easier and stick with it longer. I find pickle juice to be immensely helpful, just a shot or two at a time when needed. Potassium tablets, salt substitutes, and mineral supplements such as magnesium, calcium, and phosphorous may also be helpful.
Fasting, VLC, & Rapid Weight Loss Dangers, Warnings & Precautions:
Pro Fast and VLC:
Kidney stones may become an issue for some people embarking on a fast, and most especially a dry fast. Below is information about this problem and ways to mitigate this risk or even help remedy stones once formed.
Gallstones may also become an issue due to low fat consumption and cortisol from fasting.
HOW TO GET RID OF GALLSTONES NATURALLY (Note: the remedy on this site includes the use of epsom salt which can cause diarrhea and be dangerous especially with certain conditions. Please do your homework on the precautions and proper use of this. Consultation with a physician is recommended before using the first time).
Hydration, Dehydration, Sodium/Water Balance, Diarrhea:
*Note that too much potassium dissolved in water will have similar effects to salt water
Start slow, don't just dive right into fasting. You need to get used to it mentally and physically.
Drink enough water (if water fasting), but don't overdo it. Too much water can flush out electrolytes.
Eat healthy at least most of the time when you're not fasting
Have a shot or two of pickle juice if you feel faint or have a rapid heatbeat. Note that if you want to be in a state of autophagy, pickle juice is said to have antioxidants which may turn off the process. An alternative to pickle juice is water with a small amount of sodium and potassium (use a potassium based salt substitute) dissolved in water. A solution like this is recommended on the snake diet fasting plan. Experiment with small amounts to avoid diarrhea. Too much salt or potassium at once can be dangerous and dehydrate you.
Drink salt water in too high a concentration-I thought this would restore electrolytes while fasting. It just gave me the runs, which further depletes electrolytes. I was only adding about 500mg of sodium to 16 oz, and it was too much. This will tax your kidneys and irritate the bowel.
Crush up a multivitamin that hurts on an empty stomach and mix it in water-that doesn't help.
Exercise outside after a complete fast the previous day. Avoid heat exhaustion and don't exercise vigourously. Make sure you have electrolyte water or something to eat immediately after your workout if you're breaking your fast that day. Update: this may vary from person to person and based on how adapted you are to fasting. I managed an hour long walk on the last day of a 7 day fast and felt ok-aside from slightly more exhaustion and perhaps a little more labored breathing. Just be careful, stay close to home, make sure you take some electrolytes and water first (sodium and potassium at minimum), and monitor how you feel, stopping if you feel sick.
Break a longer fast with probiotic rich foods like Kombucha, Kimichi, or Kefir. I thought they would be perfect to break my 7 day fast with, but I learned, both from experience and research, that probiotic rich foods can stimulate the digestive system and cause diarrhea on rare occasion (such as when you've been fasting a while). These foods are great for replenishing good bacteria, but you might want to wait until you're further along in the refeeding process when your body can tolerate them.
Be careful drinking potassium (salt substitute) in water, it can have the same effect of drinking salt water (diarrhea). Too much lemon juice or baking soda can also be irritating. Make sure to take these substances carefully.