Ashlee Williams, MD (Host): If you haven't tried intermittent fasting, chances are you know someone who has. Intermittent fasting has become a popular way to manage weight and it has a ton of other health benefits, from reducing inflammation to improving blood sugar and blood pressure levels. So what's the best way to get started? Welcome to the Healthier You podcast. I'm Dr. Ashlee Williams. And today I'm talking with Dr. Amar Athwal, a double board certified family physician and obesity medicine physician at Kaiser Permanente to help us navigate the ins and outs of intermittent fasting. Dr. Athwal, thanks so much for being here.

Amardeep Athwal, MD: Dr. Williams, thanks for having me.

Host: This is such an exciting topic. Everyone's talking about what are the best ways to lose weight. So let's just start with the basics. How does intermittent fasting work?

Amardeep Athwal, MD: Well, intermittent fasting isn't necessarily a diet. Instead, it's a pattern of eating that involves only eating within a certain time frame. By not focusing on calories, but rather when you consume them, it changes how the body metabolizes food, so you end up burning more calories and more fat. When you eat carbohydrates, they're broken into sugar, which our cells use for energy.

Any energy we don't use gets stored in our fat cells. But sugar can only enter the fat cells with insulin, a hormone produced in our pancreas. When we stop eating, our insulin levels go down, and our fat cells can then release stored sugar to be used as energy. The reason intermittent fasting works is it gives our body time for insulin levels to go far down enough and long enough to burn fat.

Host: Okay. So we know that there's different ways to do intermittent fasting. Can you talk a little bit about the different ways to do it and how someone could get started?

Amardeep Athwal, MD: Absolutely. There's no one right way. There's several different ways that you can do it. And the best thing to do is choose what fits your lifestyle and what you'll be able to sustain. The other thing is to kind of start gradually and slowly ease into it. One of the most common ways is the 16/8 method.

 In this approach to intermittent fasting, patients eat every day during an eight hour window and fast for the remaining 16 hours. Any eight hour window is usually fine. Some people may choose to consume food from 8 a.m. to 4 p.m. or between 11 to 7. This is a lot easier for people rather than trying to fast for a whole day.

Another method is the 5/2 method. People eat how they normally eat for 5 days a week, but on the other 2 days, they just restrict themselves to 500 calories a day. And often those 2 days shouldn't be consecutive, but scattered through those other 5 days. Another method is to eat normally 1 day, and then fast on alternate days, so you're on and off fasting every other day.

 Finally, another method is to eat, stop, eat, which involves fasting for 24 hours, one or two days a week, and the, uh, remaining days to just eat the normal way.

Host: Got it. So with all of these methods, at some point we're not eating. So any tips on fighting hunger during these fasting periods?

Amardeep Athwal, MD: One thing, which works for intermittent fasting and even other diets, is to redirect yourself when you're hungry. So when you feel like getting a snack, instead of snacking, go for a walk, or exercise or do some other activity to take your mind off of the snack. Another important thing to do is to drink lots of water.

 Sometimes when you feel like a snack, just drink a large glass of water to kind of satiate yourself. Other things can be drinking a black coffee, tea, or bone broth. Anything to satisfy your appetite without actually eating a snack. And remember, you don't have to be perfect. This is a lifestyle modification, and you want to try to adhere to the guidelines, but if you're not perfect and once in a while you snack, you don't follow the hours exactly, that's okay.

Host: Yeah, I think that's great advice for anyone. Like, no one is perfect, so don't put that pressure on yourself to be perfect. Can you talk about some of the benefits of intermittent fasting, any association with intermittent fasting and weight loss?

Amardeep Athwal, MD: Yes, actually, intermittent fasting can help you lose weight. Many people are successful at losing weight by intermittent fasting. It pushes your body to burn fat cells during those fasting periods, which leads to weight loss. Of course, this can vary depending on other factors, including your metabolism, your diet, you know, what you're actually eating, the amount you exercise, and of course, how well you adhere to the schedule.

 Additionally, people see improved blood pressure, increased insulin sensitivity, which can help lower the risk of developing type 2 diabetes. Fasting can also promote improved brain function and protect against dementia. Some studies show that fasting reduces inflammation in the body, lowering the risk of some age related diseases. It even lowers cholesterol in some people.

Host: Okay, yeah, so fun fact, I actually did intermittent fasting. I had a baby last year, she is now a little over one years old, and after I finished breastfeeding for the year, I tried intermittent fasting, along with working out, and I was actually able to lose about 40 pounds. So it can work. Again, I tried not to, I was not perfect.

Sometimes I ate outside of the time limits that I set for myself. But I did start after breastfeeding. So what should people keep in mind if they're interested in starting intermittent fasting?

Amardeep Athwal, MD: Absolutely. And that's a fantastic weight loss. Congratulations on achieving that. Some things to keep in mind are one, when you fast matters. Some people fast in the morning and eat late in the day, but it's probably better to eat during an earlier window of 8 a.m. to 4 p.m. or 10 a.m. to 6 p.m. and have a bigger meal at the beginning of the day so you burn more calories throughout your day. If you eat late in the day, right before you sleep, your body is not as active and not burning those calories. Another important aspect is to make sure that you maintain a balanced diet. During those periods of fasting, your body can suffer if you're not getting enough nutrients, you're not eating plenty of fruits and vegetables and lean proteins.

So, even though you're doing the intermittent fasting, it is important to maintain a healthy and balanced diet to maintain your nutrition. It's also very important to stay hydrated and to drink 64 to 96 ounces of water every day. Then there are some people who should maybe avoid intermittent fasting.

 People who have eating disorders, people who are underweight, people who have a history of low blood sugar, people who are breastfeeding, as you mentioned, people who are pregnant, and children and adolescents. Additionally, people on certain medications may have to avoid it because they have to take medications with meals. And then people with diabetes, hypothyroidism, adrenal insufficiency, or other metabolic disorders should talk to their doctor before trying intermittent fasting.

Host: Got it. You talk about like talking to your doctor first. What do you tell patients who want to get started with intermittent fasting as a physician?

Amardeep Athwal, MD: Well, of course, on an individual basis, it's also important to talk to your primary care doctor before you make that endeavor. The next step would be to figure out what type of intermittent fasting works best for your lifestyle. So you want to consider your eating habits as they are, your schedule as far as work, sleep, your kids routine, and pick what fits your day better.

When you start, take it slow. You don't have to jump right into it, but slowly kind of dial back your eating pattern over several weeks. So you may not want to go into completely eating only 8 hours a day, but slowly go back from 12 hours, 10 hours, 8 hours, and ease yourself into it, if that is the pattern that you choose.

And remember, you don't have to be perfect, it doesn't have to be every day to begin with, you kind of slowly do it a few days until you're able to do it more consistently. And it doesn't have to be forever, and if it doesn't work for you, you can change to something else or back to your normal pattern.

Host: Great. Thank you. And thank you for all of this great information, Dr. Athwal. We learned a lot about different methods of intermittent fasting and its health benefits. Here are the top takeaways. 1. Intermittent fasting focuses on when you eat rather than what you eat. 2. It can promote weight loss by burning fat cells for energy and may improve blood pressure, insulin sensitivity, and cognitive function.

3. There are several different methods, including the popular 16/8 method, which is 16 hour fast and an 8 hour eating window is key. 4. Choose a method that fits your lifestyle and start gradually. Remember, no one is perfect. It's okay to experiment and see if it's a long term fit for you. 5. To manage hunger while fasting, redirect your focus to other activities like walking and drinking water to curb your appetite.

Remember that intermittent fasting is a lifestyle change and requires getting used to, so it's really okay not to be 100 percent perfect all of the time. And 6. When fasting, it's important to maintain a balanced diet and to stay hydrated. Keep in mind that fasting without a healthy diet can lead to nutritional deficits, decreased focus and side effects like dehydration, insomnia, headaches, nausea, and hair loss. Make sure to speak to your doctor to determine if intermittent fasting is right for you. For more information about nutrition and healthy eating from our experts, visit kp.org/doctor and listen to more episodes of Healthier You wherever you get your podcast.

If you enjoyed this episode, please be sure to share it with others who may find it helpful. Thank you and from all of us at Kaiser Permanente, be well.