Until recently, fasting was something you might hear about people doing for religious or political reasons. Christianity, Judaism and Islam use fasting as a way to express sacrifice, self-discipline, or gratitude.
Then you’ve got the folks who go on a hunger strike to make a political statement or to protest something they deem unjust.
But this has all changed. These days, more and more people are going without food to improve their health. There’s been an explosion of research on how fasting can extend life, support brain health and cognition – and prevent or treat cancer. Here’s the story. . .
Everyone likes a day off including your digestive system
Fasting is the practice of forgoing food and drink by choice for a specific period of time. But that definition leaves room for a number of variations of what it means to fast.
For example, “dry fasting” is when you abstain from all food and liquid for longer than 24 hours. “Water fasting” is when you only drink water during your fast. “Juice fasting” means you’re allowed to have juice while fasting, but nothing else.
Many people are only familiar with fasting in a medical setting, such as prior to surgery or any procedure that requires general anesthesia. Or you might be asked to fast before blood tests for cholesterol or blood glucose. Your doctor may even ask you to abstain from chewing gum and smoking (which you shouldn’t do anyway), because both activities can rev up your digestion, which could throw off blood test results.
This is because different processes in your body are immediately affected by consuming and digesting food. These include. . .
- Blood glucose level (also called your blood sugar level)
- Lipid profile (for cholesterol and other blood fats)
- Iron levels
- Metabolic panel (such as electrolyte balance, kidney function, and liver function)
- Renal panel (for kidney function)
- Vitamin B12 levels
- Enzyme levels (such as the gamma-glutamyl transferase, or GGT enzyme level)
All these will differ depending on whether you’ve just eaten or not. So scientists decided it was worthwhile to ask what happens to the body when it’s not busy breaking down nutrients. And that’s what led to the discovery of the positive health benefits of fasting.
The lesser-known benefits to going without food
For starters, fasting has been shown to be an effective weight loss strategy when done for just 24 hours. In fact, the latest diet trend is something called “intermittent fasting” where you eat little or nothing on certain days of the week or at certain times of the day.
According to the American Journal of Clinical Nutrition, this type of fasting can help you lose weight, lower inflammation, improve cholesterol, and improve blood sugar levels – but only when done correctly, which includes not going too long without food.
Scientists have also found some remarkable cancer benefits. In a 2007 study of breast cancer survivors, those who fasted for 13 hours or more overnight were less likely to have a cancer recurrence. This type of fasting is known as the extended overnight fast.
This version of fasting includes lengthening your overnight fast (the time you normally go without eating) to a full 14 hours, meaning you fit your regular meals into a 10-hour span.
As an example, you might finish dinner at 6:30pm and then not eat breakfast until 8:30am the next morning. This type of fasting has become popular with a large and growing public. The minimum recommended fast I usually see is 12 hours. If you can hold out for 14 hours, even better.
Even more fascinating is that fasting can help your body fight existing cancer.
According to a study published in 2016 in the journal Cancer Cell, and underscored by a similar study in BMC Cancer published around the same time, fasting is a smart move for anyone on chemotherapy.
One of the lead researchers said fasting appears to stimulate the immune system into action, activating it in a way that makes immune cells more likely to attack cancer cells. Fasting may also make cancer cells more susceptible to getting wiped out by the chemotherapy.
These studies built on other studies that showed how a person can starve their own cancer cells with a short-term fast.
Helps with other medical conditions, too
Cancer is not the only illness that’s affected by fasting. A study from the journal Cell Reports showed that a diet that mimics fasting in terms of calorie-restriction can slow the progression of multiple sclerosis, because it kills off bad cells and generates new ones.
Fasting may also help lessen symptoms of depression and may even slow the aging process. Most of the evidence for life extension is based on animal studies, but the results are eye-popping. It’s likely that consistent and disciplined fasting can add many years to a human life.
Getting back to cancer, the research results are striking because they turn the tables on what most people go through with chemotherapy – a massive loss of their immune system function. But those on a fasting diet see an increase in the levels of bone marrow cells that generate T cells, B cells, and natural killer cells.
Think of it as “body maintenance” time
Here’s a useful way to look at fasting: Food is good it’s life-giving and life-sustaining. But now and then, the body benefits from a break so it can focus on “maintenance” tasks. And when your body isn’t busy trying to process the foods you put in it throughout the day, that’s when it’s able to put energy into other areas like burning fat, strengthening your immune system, and searching out unwanted cells.
The maintenance function is what has made fasting so attractive to people who want to preserve memory and cognition and avoid dementia. It’s known that, when blood sugar is low (as it is when you fast), the brain starts consuming its own dead or ailing cells, as well as cellular waste that’s floating around between brain cells.
If you eat so frequently that blood sugar is never low, this process of garbage disposal never takes place, and the brain deteriorates.
As far as alternative health treatments go, fasting is a low-risk, high-value one that’s easy to try on your own. The easiest way to get started is to do without food for a least 12 hours, from your last meal at night to your morning breakfast. Much better is to go a full 16 hours, meaning you eat all your meals within an eight-hour window – say, between 11 AM and 7 PM.