Intermittent fasting (IF) is a term for an eating pattern that alternates between periods of fasting and eating. It is not a diet, it is an eating pattern.
Humans have been fasting throughout evolution and are able to function without food for extended periods of time. Sometimes this was the result of food scarcity. It has also formed part of major religions like Christianity, Islam and Buddhism.
Intermittent fasting simplifies healthy lifestyle efforts
Eating healthily is simple, but it can be incredibly hard to stick to. One of the main obstacles is all the work required to plan for and cook healthy meals.
With IF it’s easier because you don’t need to plan, cook or clean up after as many meals as before. It improves your health while simplifying your life at the same time.
Ways of fasting intermittently
- The 16/8 Method: Also called the Leangains protocol, it involves skipping breakfast and restricting your daily eating period to eight hours, for example from 1 pm to 9 pm. Then you “fast” for 16 hours in between.
- Eat-Stop-Eat: The Eat-stop-Eat method involves fasting for 24 hours, once or twice a week, for example by not eating from dinner one day until dinner the next day.
- The 5:2 Diet: On two non-consecutive days of the week, only eat 500-600 calories. Eat normally the other five days.
Intermittent fasting affects cells and hormones
Several things happen in your body on the cellular and molecular level when you fast.
- The body changes hormone levels to make stored body fat more accessible.
- Cells initiate repair processes, and change the expression of genes.
These changes in hormone levels, cell function and gene expression are responsible for the health benefits of intermittent fasting.
Changes that occur in your body when you fast
- Human Growth Hormone (HGH): The levels of growth hormone skyrocket, increasing as much as 5-fold. This has benefits for fat loss and muscle gain.
- Insulin: Insulin sensitivity improves and levels of insulin drop dramatically. Lower insulin levels make stored body fat more accessible.
- Cellular repair: Your cells initiate cellular repair processes when you fast. This includes autophagy, where cells digest and remove old and dysfunctional proteins that build up in cells.
- Gene expression: There are changes in the function of genes related to longevity and protection against disease.
Intermittent fasting facilitates weight loss
- IF changes hormone levels that facilitate weight loss.
- In addition to lower insulin and increased growth hormone levels, IF increases the release of the fat burning hormone norepinephrine (noradrenaline).
- Because of these hormonal changes, short-term fasting may increase metabolic rate by 3.6 – 14%.
- Studies show that people lost 4 – 7% of their waist circumference. This indicates that they lost significant amounts of the harmful belly fat that builds up around the organs and causes disease.
Note: If you binge and eat massive amounts during the eating periods, then you may not lose any weight at all.
Overall health benefits of intermittent fasting
- Weight loss: IF can help you lose weight and belly fat, without having to consciously restrict calories.
- Insulin resistance: IF can reduce insulin resistance, lowering blood sugar by 3 – 6% and fasting insulin levels by 20 – 31%. This should protect against type 2 diabetes.
- Inflammation: Some studies show reductions in markers of inflammation, a key driver of many chronic diseases.
- Heart health: IF may reduce LDL cholesterol, blood triglycerides, inflammatory markers, blood sugar and insulin resistance. These are all risk factors for heart disease.
- Cancer: Animal studies suggest that intermittent fasting may help prevent cancer.
- Brain health: IF increases a brain hormone called BDNF, and may aid the growth of new nerve cells. It may also protect against Alzheimer’s disease.
- Anti-aging: IF can extend lifespan in rats. Studies showed that fasted rats live as much as 36 – 83% longer.
Safety and side effects of intermittent fasting
Hunger is the main side effect of intermittent fasting. You may also feel weak and that your brain isn’t performing as well as you’re used to. This may only be temporary, as it can take some time for your body to adapt to the new meal schedule. If you have a medical condition, you should consult with your doctor before trying intermittent fasting.
IF has an outstanding safety profile. There is nothing “dangerous” about not eating for a while if you are healthy and well nourished overall.
Source: Authority Nutrition