Fasting isn’t a new practice, it is something that humans have been using for centuries. However, it has recently blown up in the health and wellness space. It’s a trend that certain fitness professionals and coaches are suggesting for weight loss, but it may be oversold as a magic solution for struggling dieters.
There are a few different approaches to intermittent fasting.
The first and perhaps the most common is the practice of shortening your eating window. This can be done by skipping breakfast, eating an early dinner, and avoiding all before-bed snacking. Others might take an opposite approach, eating an early breakfast, a healthy lunch, a snack before 3 pm, and then fasting for the rest of the day until breakfast. The primary goal, whether you’re fasting in the morning or evening, is to fast for 16 out of 24 hours a day.
Other, less commonly used approaches to intermittent fasting include fasting for a full 24 hours, twice a week or drastically reducing calorie intake to roughly 500 calories twice a week.
Proponents of intermittent fasting push this lifestyle change for a few specific reasons. They believe that a shorter eating window will help control appetite, result in fat loss, reduce hunger cravings, and improve the body’s sensitivity to insulin.
Does Intermittent Fasting Work?
If you want the short answer, I say intermittent fasting does work for the right people.
The longwinded answer? There is research to back this claim up. For instance, in 2018 a study was published in Food Science and Nutrition examining weight loss experienced by women using intermittent fasting compared to women who were restricting calorie intake consistently. Researchers found that weight loss between these two groups was comparable. It is also worth pointing out that the group that practiced intermittent fasting didn’t practice overeating as compensation for restrictive days, which is a concern many people express about fasting.
Insulin sensitivity refers to how responsive your cells are to insulin. Improving it can help you reduce insulin resistance and the risk of many diseases, including diabetes. Another 2018 study published in Cell Metabolism took a close look at intermittent fasting for the purpose of increasing insulin sensitivity in individuals. The results were pretty convincing, reporting increased sensitivity in individuals who practiced intermittent fasting in the morning as well as a decrease in blood pressure. Interestingly enough, even individuals who didn’t lose weight experienced these results.
How Does Intermittent Fasting Work?
The fitness community is quick to oversell a diet or lifestyle change as a magic fix. The truth about intermittent fasting is that the way it works is so much more common sense than we make it out to be.
The least-scientific and most straightforward explanation for how IF works is that it helps you naturally eat less. One study found that young men ate 650 fewer calories per day when their food intake was restricted to a four-hour window. Another study in 24 healthy men and women looked at the effects of a long, 36-hour fast on eating habits. Despite consuming extra calories on the post-fast day, participants dropped their total calorie balance by 1,900 calories, a significant reduction.
At its most basic, weight loss is always about taking in fewer calories than we are burning each day.
Think about it like this — if someone were to eat five Big Mac burgers from McDonald’s every day, they’re probably not going to lose any weight. However, if that person starts practicing intermittent fasting and cuts down their Big Mac intake from five to one or even two burgers a day, they’ve drastically decreased how many calories they’re eating, and they’re most likely going to lose weight—at least for a period of time.
Creating a caloric deficit is one of the simple ways intermittent fasting works as a weight loss (fat loss) tool. Whether you’re shortening your eating window each day or fasting for 24 hours, twice a week, you are consuming fewer calories.
Should Women try IF?
Intermittent fasting may not be as beneficial for women as it is for men. To reduce any adverse effects, women should take a mild approach to fast: shorter fasts and fewer fasting days.
For more information regarding IF specific to women, I encourage you to read Mark Sisson’s (founder of Primal Kitchen) excellent piece titled “Should Women Fast?” His conclusion to this question as it stands for now:
“I’d be inclined to agree that pre-menopausal (and perhaps peri-menopausal) women are more likely to have poor—or at least different—experiences with intermittent fasting (at least as a weight loss tool). That said, it appears to be a potentially gender-neutral therapeutic tool for chemotherapy, cancer, and age-related neurodegeneration patients.” – Mark Sisson
Is Intermittent Fasting Right for You?
Intermittent fasting isn’t right for everyone. I wouldn’t recommend this to someone who has a history with an eating disorder. I think individuals who have made a habit of over-restricting in the past should look for alternative options.
In a 2014 study published by the International Journal of Obesity, a point is made that I think is worth pointing out — whether you’re using intermittent fasting or some other weight loss measure, what successful weight loss strategies share in common is that they are simple to stick with long-term. More specifically, they need to be safe, not requiring extreme calorie reduction. They also need to be satisfying, if a diet feels overly restrictive or boring, it is so hard to stick it out for the long term.
This means that, before you commit to intermittent fasting for the long term, you need to ask yourself a few questions. Can you stick with it for the long-term? Does it provide you with a satisfying method for reducing your calorie intake? Can you use intermittent fasting with indulging in compensatory overeating when you’re done fasting?
I don’t like to see anyone using intermittent fasting as their only tool for healthy living. Fasting should be paired with eating a diet low in sugar, rich in whole foods, high in protein and blended with regular strength workouts and cardiovascular training.
Consistency is everything when it comes to fat-loss, but don’t beat yourself up when you face obstacles. If you slip up and eat a donut for breakfast, don’t think, “I’m a failure.” Acknowledge that while you may have gone off course today, you will do better tomorrow. Intermittent fasting may work for you! If you’re in a rut, consider giving IF a chance.
Intermittent fasting is one of many potentially useful fat loss methods. That being said, it is only a tool. It is not a magic fix or the ‘perfect diet.’ There isn’t a single dietary solution that works for everyone. The ‘perfect diet’ is the healthy dietary lifestyle that is sustainable for YOU! This is the type of diet that is going to give you weight loss and an overall increase in your well being, which is our real goal for any lifestyle change. If intermittent fasting happens to work for you, great! If it doesn’t, there are plenty of other dietary solutions that may be more fit for you and your fitness goals.