I’ve never completed a diet “cleanse.” When everyone else is giving up coffee, I’m blending mine with butter. Last year, if you’d asked me who was least likely to write about the benefits of intermittent fasting, I would have told you it was me.
And yet here we are, because intermittent fasting helped me increase my energy levels and lose my excess baby weight without changing what I ate . . . only when. And the more I’ve researched it, the more benefits I’ve discovered.
So what is intermittent fasting, and why is it so awesome?
Intermittent fasting (IF) is not a diet, it’s a lifestyle in which you limit food intake to a certain time window during the day. For example, I eat all my meals within a 12 hour window between 8am and 8pm, and I fast through the evening and while I’m sleeping. (This was really hard for me at first, because I was a huge late-night snacker, but it got easier very quickly.)
There are a lot of patterns of intermittent fasting, such as:
Eating all meals within a 12 hour window (say, from 8am – 8pm), then fasting for 12 hours
Eating all meals within a 10 hour window (usually 9am – 7pm), then fasting for 14 hours
Eating all meals within an 8 hour window (usually 10am-6pm), then fasting for 16 hours (You’ll often see this referred to as 16:8 intermittent fasting)
Every other day fasting (eating nothing one day, then eating normally the next)
Although there may be certain situations when longer fasts might be appropriate, more is notusually better when it comes to intermittent fasting. Extended fasts can disrupt hormone balance – especially in women – which can lead to poor sleep, fatigue, fertility issues, depression, and other problems. (source 1, source 2)
On the flipside, a daily fasting cycle works to balance the ebb and flow of leptin (the fat burning hormone), insulin (the fat storage hormone), and other hormones that we make throughout the day. According to Dr. Lori Rose, who is my co-author for this post, that’s because our digestive tract contains a “peripheral body clock” that syncs up with our 24-hour circadian rhythm, and periods of daily feasting/fasting help “set” the clock in the same way that light and dark does.
Benefits of Intermittent Fasting
Before we jump in, please keep in mind that this article is for informational purposes only and is based on the opinions of the authors. It is not medical advice and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. As always, please use common sense and speak with your healthcare provider if you have a medical condition that might contraindicate intermittent fasting or any other lifestyle change. Please see my full disclaimer here.
With that in mind, here are some of the top benefits of intermittent fasting.
#1: Weight Loss/Healthy Metabolism
Remember how I said it’s not so much about what you eat, but when? Here’s a study from Salk University that explains what I mean:
We put two groups of mice on different eating regiments for 100 days. Both groups ate a high-fat, high calorie diet. The first group was allowed to eat whenever they wanted, grazing throughout the day and night. The other mice had access to food only for eight hours at night, since mice are nocturnal. The results were astonishing. Despite consuming the same amount of calories everyday, the mice that ate on a restricted eight hours were nearly 40 percent leaner and showed no signs of inflammation or liver disease and had healthy cholesterol and blood sugar levels. The group of mice that nibbled day and night became obese, developed high cholesterol, high blood sugar, fatty liver disease and metabolic problems.” (source, emphasis mine)
Even more fascinating is the fact that when the time-restricted feeding mice were allowed to eat freely on the weekends, they still had the same lean mass ratio as mice who were restricted seven days a week. (source)
Research on humans supports these findings – this study found that daily fasting improved insulin sensitivity in women, and this one found that volunteers who ate earlier in the day lost more fat than those who ate later in the day, even though both groups were consuming the same number of calories.
So what’s happening here? As mentioned in this post on leptin resistance and how to reverse it, our fat cells do more than just store energy and keep us warm – they secrete a hormone called leptin. When our bodies have adequate energy reserves (fat stores), leptin calms our hunger. When we need more nourishment, leptin dials up our desire for food.
At least that’s how it’s supposed to work.
When we graze all day and all night, unfortunately, our bodies often lose the ability to “hear” what leptin is telling us, and we end up feeling hungry even when we have ample energy stores. Intermittent fasting encourages better leptin signaling so our bodies get the message and we feel satiated.
#2: Activates “Cleanup Mode”
Intermittent fasting triggers autophagy, which is literally translated as “cellular eating.” When autophagy occurs, a bunch of little guys called lysosomes go around gobbling up damaged cells, damaged mitochondria, and cancerous cells. These lysosomes and mitochondria are good guys, giving us energy for vitality and cellular regeneration for a vibrant life. Without them, our body fills up with cellular trash and we just can’t function as optimally as possible. Furthermore, negative results like expedited aging and disease occurs because we just aren’t taking out the proverbial trash as efficiently as we should.