Intermittent fasting is a diet that revolves around the practice of going without food for certain periods of time.
It has become a popular dieting choice for many people with varying fitness levels and goals. Typically, with intermittent fasting, individuals go without food for 16 to 24 hours at a time to improve their health. Benefits include weight loss, improved insulin sensitivity, and increased levels of human growth hormones.
What if you were to take this fasting to a whole other level and choose not to eat for a week? Would the benefits outweigh the drawbacks?
In short, the answer is no. Just because there can be benefits from not eating for a day or so does not mean that they will be magnified if you continue this pattern for a whole week. While you will lose weight from the calorie restriction, there are a lot of potentially negative effects that can develop from putting your body into a state of starvation.
So, what are the effects of this form of extreme fasting? Let us start at the beginning.
For the first 8-12 hours nothing special happens, as your body is likely still digesting your last meal. Digestion takes the food that you have eaten and breaks it down into glucose, which provides energy to your body.
Once that glucose storage has depleted due to lack of food, your body begins to use your glycogen stores for energy. The glycogen is taken from your liver and muscles and gets converted into glucose to keep you going.
Once you have run out of both glucose and glycogen, your body will enter into a state of ketosis. This may sound familiar as it is the main goal of the keto diet, with the difference being that you are supposed to eat a high-fat, low-carb diet to enter ketosis, not stop eating altogether.
While in ketosis, your body begins to burn fat cells to create ketones that can be used for energy. If you have not been eating at all, this means your body will use your fat stores to create the ketones, which will result in significant weight loss.
The amount of time your body stays in this fat-burning state varies depending on how much body fat it has in storage. Once it has burned through all of the fat, then it starts using amino acids from your muscles to make glucose for energy, as these are all you have left for fuel. Basically, your body starts eating itself!
While all of these things are going on in your body, you may notice various effects, especially after the first 72 hours. Keep in mind that everyone is different, so the extent to which you notice any, or all of these effects depends on the person.
The process of ketosis may be enough to fuel most of your organs, but unfortunately, it is not enough to fuel one of the most important: your brain. Your brain cannot use ketones as effectively as the rest of your body, as ketones can only provide about 75% of its energy requirements. Have you ever noticed that people sometimes seem unfocused or short-tempered when they are hungry? And this is usually after not eating for just a few hours!
Your brain is so dependent on glucose that once it starts to run out and blood sugar levels decrease, you may have difficulty concentrating on what you are doing, which can then cause you to lash out at others.
For example, you may make a point of concentrating when you are speaking with important colleagues, but once you are relaxed you may lash out at people you are most comfortable with, like family or friends. One study has linked low glucose levels to higher aggression between married partners.
You Will Lose Weight
If your body is using up its fat stores and then moves on to burning muscle tissue, you can lose quite a bit of weight. The amount of weight you lose depends on how much you weighed when you began fasting. While it can be nice to drop some weight quickly, you do need to be careful.
One study states that after losing 10% of body weight, those who are fasting should be monitored for severe side effects of starvation. If they continue fasting to the point where they have lost 18% of their body weight, then they run the risk of suffering from the most serious consequences.
While you will experience weight loss not eating for a week, you will likely put the weight back on pretty quickly if you resume the diet you were following before you began fasting. If you are looking to lose weight and keep it off long-term, then fasting for a week is probably not the best choice.
There are so many potential side effects when your body is put into starvation mode, including:
If you are starting out perfectly healthy, it is entirely possible to not eat for a week and not experience any severely negative consequences. However, many of the most beneficial effects from not eating for a week can also be achieved by doing intermittent fasting, which requires only 16-24 hours without eating at a time.
Before you decide to try any type of fasting, talk to your doctor. This is especially important if you are under 18, pregnant or breastfeeding, have or have had an eating disorder, and/or have any other underlying health conditions. You may be more likely to experience the most negative consequences from not eating for a week compared to others, so take every possible precaution.