Intermittent Fasting 101

Intermittent fasting, a relatively new approach to diet and nutrition, has been getting buzz lately because of its success battling chronic inflammatory conditions—and helping with weight management. Here, Shana Hussin, RDN, a registered dietician and author of Fast To Heal: A 5-Step Guide to Achieving Nutritional PEACE and Reversing Insulin Resistance, outlines how she came to embrace intermittent fasting, what it entails—and whether it might be right for you. 

How Shana discovered intermittent fasting

Shana spent nearly twenty years recommending traditional dieting and nutrition strategies to her clients, and they helped—initially. “We would see progress for a couple of months,” Shana recalls. “Then the client would fall off and I’d lose track of them.” Frustrated by the lack of long-term improvement, Shana transitioned from being a dietician to what she calls a “health coach.” The new position was still in a hospital setting, but involved counseling employees and creating a healthy work environment for them. Even then, however, Shana found herself working with the same employees over and over as they struggled with weight and wellness issues. The traditional tips and strategies just didn’t seem to create long-term change.

“Then I started to have health issues myself, my son got ill with digestive problems, and none of the standard approaches or conventional medicine helped,” recalls Shana. “This made me question, even more, the recommendations I’d been giving, and I quit the nutrition and dietetics field and became a substitute teacher for a few years.” 

In 2019, Shana decided to try counseling again and took a job helping in a weight loss clinic. There she discovered Jason Fung’s book, The Obesity Code. “He was the first to bring the idea of fasting into the mainstream. I read the book and thought, ‘Why wasn’t I taught these methods as a practitioner? They’re simple to implement.’ It made so much sense. I started doing intermittent fasting myself, not for weight management, but to see if some of my other health issues could be helped. And I was pleasantly surprised that my body composition changed for the better even though I wasn’t working toward that,” says Shana. 

“I decided to do a small pilot program with twenty people at the clinic. We began right before Halloween and ended after New Year’s, and people did fabulously, even during that stressful time of year. Not only did everyone lose weight, many also said they slept better and their chronic aches and pains went away too. At the end of the pilot program, I was like, ‘This is what I want to do. I’m passionate about this.’”

So, Shana left the clinic in order to see clients fulltime and help them incorporate intermittent fasting into their lives. She also wrote her book on the topic (link above), started a companion podcast, Fast To Heal Stories, and runs 28-day challenges online at “I have seen more progress and healing with the people I’ve introduced to intermittent fasting than I saw for the twenty years I recommended standard approaches,” says Shana.

What exactly is intermittent fasting?

“Intermittent fasting focuses more on the when part of eating and less on the what,” explains Shana. “Why do you want to limit the time frame when you eat? Traditional nutrition counseling says to eat all day long: Eat your breakfast within an hour of when you get up, eat at least three meals a day, and eat small snacks to keep your metabolism up. However, what I’ve learned is all-day eating can cause an insulin buildup.”

When insulin builds up, the surplus of energy it creates has nowhere to go…so it ends up in your fat cells. “All that eating means we are perpetually storing fat, rather than burning it. It’s that simple,” says Shana. But, when you don’t eat for longer periods of time, you can keep insulin levels quiet and low, causing your body to have to look for a different fuel source. “Without the overload of insulin, your body is forced to find other sources of energy, and it pulls from stored carbohydrates or stored sugar in your muscles. And when that’s gone, it goes into what I call the deep freezer in your body—fat,” says Shana. “Your body doesn’t want to go there. It’s like, ‘I want the carbohydrate to burn because that’s easy.’ But when you don’t eat for long periods of time, your body has to finally tap into the fat.”

In addition to weight loss, Shana says there are also myriad health benefits from intermittent fasting. “Giving your digestive tract a break for sixteen to eighteen hours at a time can help support autophagy, a process during which the body cleans out and recycles substances that shouldn’t be there anymore,” she says. Autophagy also allows the immune system to more capably fight a virus or bacteria—and to get rid of waste that might be causing inflammation, the root cause of all disease. 

Other benefits Shana’s clients have seen:

  • Relief from Polycystic Ovary Syndrome (high insulin is a cause of this condition)
  • Clearer skin 
  • More energy
  • Improved fertility
  • Better management of diabetes, high cholesterol, and heart disease

If you’ve never tried intermittent fasting before, Shana suggests starting with sixteen hours of fasting. “Stop eating after an early dinner, then sleep, and you can get in a good twelve to fourteen hours of straight fasting right there, without skipping any meals,” says Shana. To extend from sixteen to eighteen or even twenty hours, just slowly start bumping the time back that you eat your first meal. Then, in that afternoon-to-early evening window, eat two full meals. Shana says most people follow this protocol five to six days a week, with a seventh day called a “feast day,” where they expand the eating window and eat three full meals. 

When you are fasting, Shana says to keep things clean. That means plain, carbonated water (no flavor), black coffee (caffeine is fine as long as you’re not adding sugar or creamer), and plain teas. “If you add anything, even if it’s just Stevia, it may stimulate a hormonal or insulin response because you drink it and your body says, ‘Something sweet is coming. I better release insulin.’”

When you are eating, Shana says not to bother counting calories. “I try to get my clients away from calorie counting because your body doesn’t recognize calories. Your body is not like, ‘I’ve had 1,500 calories. Anything more that I eat now I’m going to start storing it as fat.’ What your body does recognize are foods that are nutritious, filling, and promote satiety,” she explains. Similarly, your body doesn’t recognize foods that are ultra-processed, so feeding yourself a steady diet of processed items can leave you feeling perpetually hungry. “When you sit down to a meal, it should have a healthy fat, a natural protein, and a fruit or vegetable. Those are the foods our bodies have nutrient sensors for,” says Shana. “If you focus more on foods that are giving you nourishment and fullness, you’re naturally going to eat what you need and stop when you’re full.” 

Is there anyone who shouldn’t fast?

Shana says nearly every adult can try intermittent fasting, but she doesn’t recommend it for children and pregnant/nursing women. “If kids want to work with me, and they are suffering from childhood obesity, I will focus more on eliminating snacks and not eating in the evening after dinner. Just eating three square meals a day, balancing those meals, and getting the processed foods and sugary drinks out can work wonders for kids,” she says. Teenagers, she says, are a case-by-case basis. “If they are sixteen or older, sometimes they can do a bit of fasting,” says Shana. “My daughter is seventeen, and she usually doesn’t eat until lunchtime because she’s found it helps her acne.” 

Want more scoop on intermittent fasting from Shana Hussin? Check out Episode 3: The New Un-Diets on The Beauty Construct podcast, now available for download download on Spotify or Apple Podcasts. You can also follow Shana Hussin on Instagram, @shana.hussin.rdn, or visit her website at