Starvation vs Fasting
There is a huge difference between how the body deals with starvation and fasting, even though both involve eating less. The answer is a little bit counterintuitive. Both conditions abstain from food, however how the body handles them is very different. During a water only fast, the lack of food forces the body to revert back to our hunter gather days. In order to hunt or forage for food the body needed energy. To obtain the needed energy the body switches from burning carbs and proteins to stored fat. Stored fat has more than twice the energy per gram than either protein or carbs. On a “fast” energy levels actually go up. During long periods of starvation or heavy exercise (ten or more days) the available calories are less than the daily basal metabolism rate (BMR) the body is accustomed to, roughly 2000 cal/day for the average man. In averageJoe’s experience if you exceed your daily BMR by more than 5-10% your metabolism will drop an equal amount. BMR is different from your daily calorie intake. Your daily activity calorie intake will be anywhere from 20% to 60% above your BMR depending on your activity level.
LOF-Absolutely no food is fasting – Which is very good for you!
The difference between starvation and fasting is duration. From personal experience, your BMR appears to change in as little as 10 days. The process does not appear to be balanced. Slowing down your BMR occurs much more quickly than anything that can speed it up. In AnAverageJoes opinion, once your BMR slows down, any excess calories above the new BMR set point will spike your blood sugar and the additional glucose will be stored as fat. This is the reason why any calorie reduced diet or massive increase in calorie expenditures (ie 2 hours in the gym every day) works for a week or two then ultimately fails. In AnAverageJoes opinion, to avoid slowing down your BMR, you need to take a break once every seven days. Believe it or not the starvation impact on BMR has been known for thousands of years. Exodus 34:21 “You shall work six days, but on the seventh day you shall rest; even during plowing time and harvest you shall rest.”
LOF – Every seven days, during any diet have a cheat day, where you eat your normal calories.
Humans before the availability of 24/7 food, fasted all the time. In fact our bodies are optimized to fast.
If no food is present, then the body will systematically use the food stores of “glucose” in the blood and cells. Optimal blood sugar is around 4g of glucose, which is not a lot (16 calories). Once the “glucose” is used up in the cells/blood the body starts to burn “glycogen” which is “chains of glucose” found in the liver and muscles. After 24-72 hours of no food the body will switch to using the “fat” energy stores in the adipose tissue for energy. Fasting does NOT make muscles weaker, it does the opposite. BTW Glucose is the basic food for all human cells.
LOF- When blood sugar is low and all stores of glucose/glycogen (blood, cells, liver, muscles) are exhausted the liver will produce ketones from fat stores.
Ketones can be consumed by all healthy cells within the body. Evidence exists that ketones burn chemically cleaner than glucose.
A interesting fact about ketones…ketones CANNOT be consumed by cells who’s mitochondria have been damaged by disease or cancer. In fact, cells with damaged mitochondria (a cells energy engine) are forced to produce energy through glucose fermentation instead of the normal oxidization, a metabolic process 18 times less efficient. This is a huge finding. It hints that cancer cells can be starved or the growth rate greatly inhibited by removing all carbs from your diet.
LOF- This is the scientific basis for therapeutic calorie reduction to treat illness.
During a fast, glucose levels will remain stable and your basal metabolism will increase. Your body will switch from using carbs and proteins as fuel to fat. During a fast your body willingly gives up calories and give you the energy to search for more.
LOF – Reduced caloric intake below your BMR is starvation. – This is bad!
Your body will reduce BMR to match the reduced caloric intake or increased caloric expenditure due to exercise. (lose – lose situation)
Glucose levels will vary. Causing period of intense hunger, cravings, feelings of low energy, headaches, along with an inability to concentrate.
Your body is using mainly carbs and some protein as fuel. Your body is trying to hold onto and stretch every calorie as long as possible. Your body will store any excess calories in adipose tissue. (Fat). From experience your body will kick into starvation mode anytime caloric intake is reduced below the BMR for 10 or more days. In order to give up calories the body must be tricked into believing it will get enough calories to satisfy your daily BMR.
LOF- Once your metabolism has slowed it will not return to the old levels without substantial intervention. (Drugs or building muscle)
This is the end result of all long term diets that increase exercise or reduce calories below the BMR setpoint- without exception!
This is why 99% of all calorie reduced diets FAIL long term and the eat less move more is the completely wrong approach.
[Link to Minnesota Starvation Experiment]
Fasting
It normally takes half-a-day to use the glucose in the blood and cells. For a healthy person, without a fatty liver it takes 1-2 days to use the glycogen (stored glucose chains) stored in the liver and muscles. The pancreas releases a hormone called glucagon to initiate the transformation of glycogen to glucose. To achieve a state of Ketosis – takes 3+ days depending on how fatty your liver is. To burn fat instead of carbs you must be in a state of Ketosis. The body turns stored fat and amino acids into glucose through a process called “gluconeogenesis.” Your body is perfectly happy being in a state of Ketosis unless you are a type I diabetic. Diabetics can suffer from diabetic ketoacidosis which can be life threatening.
The optimal time to fast is highly controversial.You need to fast long enough to reduce blood sugar/insulin levels and put your body into ketosis but avoid slowing down your metabolism. The point to remember is that the body will not burn fat as a fuel in the presence of sugar (high insulin). So any cleanse or fast that includes sugar is self-defeating. The optimal fast period from consensus appears to be 7 to 10 days.
The best way to determine your state of Ketosis is through a blood test. In AnAnverageJoes experience the Freestyle Precision Neo blood glucose and ketone monitoring system works very well. (note the test strips are expensive, .75+ cdn each for glucose and 2.50+ cdn each for ketones)
Fasting not only controls insulin levels, it can reduce gut inflammation, and blood inflammation markers.
Fun fact – Longest recorded fast was 382 days conducted under strict medical supervision. The patient weighted 456 pounds at the start and 180 pounds in the end. He consumed nothing more than vitamins, minerals and water during the entire fast with no adverse health effects. Potassium and sodium were key supplements during the year plus long fast.
There are many types of fasts. Click on the button to further explore why fasting is so beneficial.