What is intermittent fasting?
Intermittent fasting is an eating style that has blown up over the past few years. Rather than focus on what you can or can’t eat, it focuses on when you can or can’t eat. Think: meal timing vs. meal planning. The diet alternates periods of eating with periods of fasting. That being said, there are tons of ways to do it.
Multiple day fasting
This is definitely the most extreme type of fasting and also the riskiest. In this type of fast, people might choose to go several days without food. It’s typically only used in clinical settings to treat or manage certain medical conditions and is monitored closely by a medical team, meaning it’s never usually recommended for the average person looking to lose weight.
Alternate day fasting
Alternate day intermittent fasting is another type of fasting where people eat every other day. With this approach, people typically go 24 to 36 hours without food, then eat up to two days worth of calories over the course of 12 to 24 hours. Some people try this out as a weight loss strategy, but it’s also used in clinical settings.
This is the most common type of fasting people use when trying to lose weight. Daily intermittent fasting breaks up each day into 2 periods: fasting and eating. During the fasting period, people may go without food for anywhere from 12 to 23 hours. During the eating period, people will eat their daily allotted calories, typically distributed among 1-3 meals, and sometimes snacks. One of the most common approaches is known as the 16/8, which involves a 16-hour fast, followed by an 8-hour eating window. For example, someone might eat their first meal at 12:00pm, stop eating by 8:00pm, and fast overnight until noon the next day. A more extreme, but also common approach is the 20/4, where someone might eat their first meal of the day at 2:00pm, for example, in which case they’d finish eating by 6:00pm that day.
There are some benefits to intermittent fasting
It’s important to note that of the proven evidence for any benefits of intermittent fasting is either in mice or people with neurological or metabolic conditions.
People who are Team Intermittent Fasting will tell you that fasting is will solve any and all of your problems.
Some of the most common benefits you’ll hear people dote on include:
- Increased energy, focus, and mental clarity
- More satisfying meals (since you’re usually eating fewer, larger meals)
- Greater fat loss
- Improved biomarkers — like cholesterol or blood sugar
Problem is, a lot of this “evidence” is self-reported and anecdotal — it’s hard to really measure what it means to have “more energy,” and whether or not this “benefit” is actually just a placebo.
We’re all for a good placebo effect — if it works, it works.
But when it comes to the benefits of intermittent fasting for people looking to lose weight, the research is young and we don’t really understand the potential long-term impact. And that’s something we have trouble endorsing.
Right now, there’s simply no evidence that indicates that this is an any more effective weight loss strategy than the rest. And people can experience similar benefits from a whole foods-based diet (treats included!).
But most people find intermittent fasting really challenging
In the short-term, intermittent fasting will help most people lose weight. As will going on a juice cleanse. Or eating cabbage all day. Or drinking shakes every day. Or cutting out carbs completely. Or eliminating junk food entirely. No sugar coating here. Just sugar.
But when it comes to keeping the weight off?
That’s a whole other story.
At Noom, our philosophy’s pretty simple: If you’re not going to keep up with something forever, there’s no point in doing it now.
For most people, fasting simply isn’t sustainable.
It’s not surprising that fasting can impact someone’s ability to workout, in terms of both time and intensity. Although exercise plays a lesser role in weight loss, you could be missing out on all the other benefits of staying active.
Most importantly, let’s face it: Nobody likes feeling hungry. And this is probably the number one complaint of people who try intermittent fasting. It’s hard.
Many people feel restricted and deprived throughout the fast, which can make them hyper-focused on food when their not “allowed” to eat it. Most importantly, this often leads to overeating when people are “allowed” to eat and also unhealthier food choices.
Fasting can also be stressful — both psychologically and physiologically. Having to plan fasts around meeting a friend for brunch or enjoying a date night with your partner? That doesn’t sound fun. And your body doesn’t think it’s fun either. If done for a long period of time, fasting can be interpreted as a “stressor” by the body, and our bodies produces cortisol in response to stressors. Cortisol, our body’s main stress hormone, is associated with fat storage and muscle breakdown.
People who try intermittent fasting also report sleep disruptions, disturbances, and poorer sleep quality, which can lead to poorer food choices, and in itself is another important variable in the weight loss equation.