Fasting. Going without food or drink for an extended period of time.
There are all kinds of fasts, but the fasts I looked at and practiced were no calorie fasts or water only fasts. In no case did I consider any kind of fast that required not drinking water! I don’t see a lot of research on dry fasting, but I do see many warnings of its dangers, but that is a topic for another time. The fast that I considered and practiced were no calorie fasts, some of which were water only fasts. Liquids are permitted on these no calorie fasts, mostly water, but other liquids such as tea or coffee or bone broth would be permitted.
Since last November I’ve fasted about 15 days with 5 days being the longest in length. In all but my most recent fast, I made the mistake of not drinking enough water. I intended the fast that lasted 5 days to go longer, but my legs started to hurt very badly. After I drank some water, the pain subsided only to return an hour later. Since I had a long auto trip and responsibilities the next day, I elected to end the fast at that point. It is better to proceed cautiously in these matters.
Drinking water on these fasts is particularly important in order not to get dehydrated. A good guide is to drink (in ounces) about half your body weight (in pounds). I just completed a 3 day fast, but I made sure to drink lots of water.
In preparation for each of these fasts, I ate a low carbohydrate high fat or LCHF diet for a few days. My diet for the last several months has been mostly LCHF, but not ketogenic. What is the difference? Well, there are many LCHF diets. Any diet where the amount of dietary fat is greater than 50% of the calories you eat in a day while keeping protein constant can be called LCHF. All such diets will, given some time, reduce the average level of insulin in the blood in people who suffer to some degree with hyperinsulinemia or high blood insulin levels. A ketogenic diet is a more restrictive form of LCHF diet. It requires that 75% of your daily calorie intake consist of fat, and only 5% consist of carbohydrate with the remaining being protein. The very low carb and moderate protein causes your body to burn up its stores of glucose and to convert to burning fat. When glucose (blood sugar) is not available, your liver will convert fatty acids to ketones** which most of your body can use directly for energy in place of glucose. This is a state of nutritional ketosis.***
To be clear, in the days before I started any 3 or 5 day fast, I ate a strictly ketogenic diet for a few days in order to induce nutritional ketosis before I began the fast. I believe this helped the fasts to be more effective, but my reason was psychological. I simply found it easier to resist eating at the start of a fast after being in nutritional ketosis.**** I was able to cook and prepare food for others and be around food without succumbing to foods allures.
How did this affect my health? On this I don’t have concrete before numbers to share, so all I can give is my testimony. In all three previous blood tests I had in the last 20 years, my cholesterol was high, my triglycerides were high and in the two more recent tests prior to this year, my HDL was low. But since last August, I have sharply reduced my sugar consumption, and in the last three months have fasted for 15 days in total.
I have now had a new set of blood tests. I made a mistake, however, in having these test done on the third day of a fast, a fast that followed most of a week of nutritional ketosis. That’s important.
Here were my most recent Lipid Panel numbers:
- Total Cholesterol 265 mg/dl or 6.85 mmol/l
- HDL Cholesterol 62 mg/dl or 1.60 mmol/l
- LDL Cholesterol 183 mg/dl or 4.73 mmol/l
- Triglycerides 87 mg/dl or 0.98 mmol/l
(See http://www.onlineconversion.com/cholesterol.htm for a conversion tool to convert between American and European units of measure.)
The problem with these measurements is that my 3 days of fasting and prior ketogenic eating has likely distorted the numbers from what they would be on a more normal diet. The high LDL Cholesterol is of major concern to my doctor.
Nevertheless, I found great encouragement in the relatively high HDL and low Triglycerides. The medical profession looks for HDL values to be greater than 40 and for triglycerides to be under 150. These are huge improvements over anything I have had for the last 30 years.
The high LDL is likely due to the fasting. I was tipped off to this phenomena by the self-experimentations performed by David Feldman, a software engineer by trade, but someone who has made a name for himself in the world of Ketogenic diets. Normally, people on ketogenic diets report excellent improvements in lipid blood panel numbers. But David is an exception. He is what is called a hyper responder. While on a ketogenic diet, his blood cholesterol skyrocketed and remains high. That lead him to undertake a series of experiments accompanied by an epic level of blood testing. What he found is worth reading about at www.cholesterolcode.com. One of his experiments was with a 3 day fast to see what effect, if any, a fast had on cholesterol levels. Sure enough, after the fast, his LDL cholesterol (aka LDL-C) shot up 84 points. It returned to pre-fast levels after refeeding. His HDL cholesterol was unaffected. You can read about it here: cholesterolcode.com/the-fasting-disaster/
The spike in LDL is easily explained. LDL carries fat in the blood to the tissues for burning. When you are fasting, you necessarily draw on your fat stores for energy and will require more LDL for transport.
There is good research backing up my belief that fasting temporarily elevated my LDL. See Fasting Increases Serum Total Cholesterol, LDL Cholesterol and Apolipoprotein B in Healthy, Nonobese Humans. Ten non-obese healthy adults fasted for seven days. During that time:
- The average total cholesterol went from 4.90 to 6.73 (189 to260).
- The average LDL cholesterol went from 2.95 to 4.90 (114 to 189).
- HDL and triglycerides were unaffected.
So, my double efforts having greatly reduced by sugar consumption and fasting appeared along with some LCHF eating appears to have paid off in two ways. My HDL and my triglycerides are much improved and are pretty good.
** The common ketones are beta-hydroxybutyrate (BHB), acetoacetate and acetone.
*** Being in nutritional ketosis is not the same as being keto-adapted. Once you are in nutritional ketosis, the body will make changes and adaptions of many types that will take a few weeks (up to 12 weeks in some cases) before you are keto-adapted. Also, nutritional ketosis should not be confused with ketoacidosis, a serious medical condition that occurs in type 1 diabetics when they do not get their insulin. The body will have both high blood sugar as well as high blood ketones which the liver produces due to very low insulin levels.
**** There is a simple explanation for this also. When your stomach is empty, it secrets the hunger hormone ghrelin causing you to feel hunger. After you eat, the level of ghrelin drops within the next hour or so. But, if you ate primarily carbohydrate, the ghrelin levels will subsequently go back up. But if you ate primarily higher protein or fat, the ghrelin levels stay down for much longer. We commonly experience these phenomena when eating Chinese food, known for being high in carbohydrates. Once we eat it, we are hungry again not long after the meal, but more fat laden meals satiate us for much longer.
Perennial Longevity 