Intermittent Fasting

Episode 99: Intermittent Fasting 99. 

By Danish Khalid, MS4; Sapna Patel, MS4; Ross University School of Medicine. Comments by Valerie Civelli, MD; and Hector Arreaza, MD.

Intermittent caloric restriction may seem like a new trend, but Sapna and Danish discussed that actually fasting is practiced in different cultures and it has many health benefits, including weight loss. .  

This is the Rio Bravo qWeek Podcast, your weekly dose of knowledge brought to you by the Rio Bravo Family Medicine Residency Program from Bakersfield, California. Our program is affiliated with UCLA, and it’s sponsored by Clinica Sierra Vista, Let Us Be Your Healthcare Home. This podcast was created for educational purposes only. Visit your primary care provider for additional medical advice.

D: Welcome and thank you for tuning back to our Nutrition series! Today, we want to give a shout out to one of our listeners. She brought up a topic that has recently gained public interest. Intermittent fasting. So, if you’re listening, Hina Asad, this one's for you! Let’s jump in! 

V: 2/3 women are overweight and obese. 1.5 pounds gained/yr on avg age 50-60’s.

S: So like we said earlier, intermittent fasting has recently gained much public interest as a weight loss approach. Or should I say, revitalized itself, as it has been around for years. It describes an eating pattern in which you alternate between periods of eating and fasting (or not eating). The length of each fast can vary in duration.

A: There are feasting and fasting periods, or fed states and fasting states. What is more effective: Intermittent restriction of calories or continuous restriction of calories? 

D: Before we dive in, let’s go back. We know that calorie reduction has been consistently found to produce reduction in body weight and improve overall health. We talked about how to calculate our basal metabolic rate and subtracting calories from our daily caloric intake to result in weight loss. However, this can be difficult to sustain over a long period. Additionally, it requires that you adjust your caloric needs every so often as you lose weight, which can further make it difficult. So how is intermittent fasting different from this?  

S: Well, in contrast to calorie reduction, intermittent fasting focuses on when calories are consumed and the total quantity consumed. Intermittent fasting works through an altered liver metabolism, referred to as the “metabolic switch.” It’s where the body periodically switches from liver-derived glucose to adipose-derived ketones. In doing so, it stimulates an adaptive response including improved glucose regulation, improved insulin sensitivity, and increased stress resistance via conditioning.

V: When you eat is more important than what you eat. Benefits: reducing cancer, Alzheimer's, DM risk, better sleep, less hangry(*find evidence). 

D: What happens when we fast? In our previous podcast we mentioned ketosis, but let's talk about the physiology behind fasting.

Feeding: blood sugar levels rise as we absorb food and insulin levels rise in response to move glucose into the cell. Excess glucose is stored as glycogen in the liver to convert it to fat.

S: Postabsorptive phase (6-24hrs after beginning fasting): Blood glucose and insulin start to drop. To supply energy ,the liver starts to breakdown glycogen, releasing glucose. Glycogen stores last 24-36hrs. 

V: Insulin levels are low, and fat stores are available and improves mental clarity

D: Gluconeogenesis (24hrs - 2 days after beginning fasting): Glycogen stores run out. The liver manufactures new glucose from amino acids called “gluconeogenesis” ( literally “making new glucose)

S: Ketosis (2- 3 days after beginning fasting).

A: Autophagy: “Auto” means self and “phagy” means eat. So the literal meaning of autophagy is “self-eating.”

S: The protein conservation phase (5 days after beginning fasting): High levels of growth hormone maintain muscle mass and lean tissues. The energy for basic metabolism is mostly supplied by fatty acids and ketones. Blood glucose levels are maintained by gluconeogenesis using glycerol. Increased adrenaline levels prevent any decrease in metabolic rate. There is a normal amount of protein turnover, but it is not being used for energy.

V: How long should we fast for? 

D: Fasts can range from 12 hours to three month or more. We can categorize them as short (<24 hours) and long (>24 hours). However, shorter regimens are generally used by those mostly interested in weight loss. The short daily fasting regimens can be divided into the length of fasting - 12 hours fasts, 16 hours fasts, and 20 hours fasts. 

S: Daily 12 hour fasting introduces a period of very low insulin levels during the day with 3 equally spaced meals throughout the day. This prevents the development of insulin resistance, making the 12 hour fast effective against obesity. Although a great preventative strategy, it is not the most effective at reversing weight gain. 

D: Fun Fact: In years past, the 12 hour fasting period was considered a normal eating pattern. This probably explains why prior to the 1970s, there was much less obesity. It wasn’t until the 1970s when the USDAs made dietary changes making a higher-carb and lower-fat diet a staple. That’s when obesity started to rise. 

S: On the other hand, during the 16 hour fasts most people skip the morning meal to account for the extra hours. In this regimen, you have an 8-hour eating window period, this is why it’s also called time-restricted eating. Although you can still eat 3 meals most people tend to stick to 2 meals. The 16 hour fast certainly has more power than the 12 hour fast, but it should be combined with low-carb diets to allow for a slow and steady weight loss. 

A: Feasting periods should not be so liberal, and over time it becomes easier to control hunger. 

V: Feeding hours: healthy fats, proteins, fish, avocados, grass fed butter, unprocessed carbs (especially Low glycemic berries, squash, quinoa, vegetables, Low sugar, low alcohol intake

… eating healthy basically.

D: Fun Fact: A Swedish bodybuilder named Martin Berkha popularized this regimen, which is why you will also hear it being called the LeanGains method. 

V: Skipping breakfast reduces caloric intake by 20-40%, addresses visceral fat.

S: Lastly, the 20-hour fasting regimen, also known as “the Warrior diet.”  Ancient warrior tribes such as Spartans and Romans devised a “warrior diet” in which all meals are eaten in the evening during a 4 hour window. This results in a 20-hour fasting period each day. This diet also emphasizes natural, unprocessed foods and high-intensity interval training.

A: Summary: 12-hour, 16-hour, 20-hour. Dr. Jason Fung also recommends 24-hour fasting. It is basically skipping breakfast every day and skipping lunch 3 times a week. “Hunger is your friend”.

D: Before we move forward, I just want to add that not all fasts are the same. For instance, I’m a Muslim, and there’s a month where we fast for religious purposes, called Ramadan. During this time we fast from sunrise to sunset, or dawn to dusk. In contrast to traditional fasting, this fasting differs in that we don’t eat or drink anything. Even water. Whereas in intermittent fasting it’s different. Now, there have been studies done where they studied individuals during this time to see if there was any weight loss during this period. It was found that people typically lost about 1-2 pounds of weight. However, I do want to clarify this weight loss could be fat loss or muscle loss. 

A: Another group of people who fast are Mormons. They traditionally fast once a month, the first Sunday of every month. It’s a complete abstinence of food and water for 24 hours, skipping 2 meals. Fasting periods are linked to improve your spiritual well-being as well. 

S: Certain Hindu festivals and holy days require devotees to observe fasting as part of their

 worship. 

For example, Navarātrī, the nine-night celebration that occurs yearly. Some people take only water during these nine days, while some eat fruit while some eat one meal a day. 

Hindus will observe fasts of varying strictness depending on individual beliefs or practices. Here are some examples of common fasts observed by Hindus:

not partaking any food or water for a set number of days.

limiting oneself to one specific vegetarian meal during the day.

eating or drinking only certain food types for a set number of days.

Avoiding eating certain food types for a set number of days.’

S: So what can I consume when I fast? Do I have to completely stop eating and drinking for those hours?

D: Only certain fluids can be consumed during fasting periods: water, tea and coffee ( iced or hot) and homemade bone broth. It's important for you to drink water frequently throughout the day. You can enjoy flat, mineral or carbonated water.  

V: While Fasting: ok to have coffee, tea and water. Fasting creates a state of alertness.  

S: What can you add to your water? Limes, lemons, sliced fruit (do not eat the fruit itself), vinegar, Himalayan salt, chia, and ground flaxseeds ( 1 tbsp in 1 cup water). Do not add sweetened powders even if it's sugar-free.

D: You can consume up to 6 cups of caffeinated or decaffeinated coffee on a fasting day. Black coffee is preferred, but you can add up to 1 tbsp of certain fats in your coffee. These include: coconut oil, medium chain triglyceride oil (MCT oil), butter, ghee, heavy whipping cream (35% fat), half and half, whole milk, ground cinnamon for flavor.

V: Ghee butter is clarified butter with no lactose. 

A: You can curve appetite by drinking water, eating grains of salt, and drinking pickle juice (use a straw to avoid dental problems)

S: You can consume unlimited herbal tea during your fasting period.  I know Danish and I both are Tea Connoisseurs. Right Danish? Teas can suppress your appetite, lower your blood sugar levels and are otherwise beneficial (positivi-tea). Bitter melon tea, black tea, cinnamon chai tea and oolong tea, help lower blood sugar levels. Peppermint tea and green tea help suppress appetite. Peppermint is good for GI discomfort such as gas and bloating.

A: Peppermint oil is good for IBS.

D: It's not uncommon to experience some lightheadedness during your first few days of fasting periods. This is often caused by dehydration and decreased levels of electrolytes. An easy remedy is a good homemade broth. Both vegetable and meat or bone broth will work. Things you can include in your broth: any vegetable that grows above the ground, leafy greens, carrots, onions, bitter melon, animal meat and bones (mostly bones, any animal), Himalayan salt, any herbs or spices, ground flaxseeds. Avoid vegetable puree, potatoes, yams, beets or turnips and store bought broths. (Dr. Fung).

A: This is the end of this part on “How to fast”. Some people think fasting includes being hungry the whole day, but the “hungry” feeling goes away after 1 hour, and you learn to recognize the cues from your body about hunger and satiety. 

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Now we conclude our episode number 99 “Intermittent Fasting 99.” This is not a complete guide to fasting, it’s only a brief overview. Fasting has become a new nutritional trend with proven benefits. Remind your patients that one of the secrets of fasting is “delay, don’t deny”, meaning they can delay eating a few hours and then enjoy what they like the most. Sapna, Danish and Dr. Civelli also reminded us to eat with moderation after breaking our fast to maintain the benefits of fasting. Even without trying, every night you go to bed being a little wiser.

This week we thank Hector Arreaza, Sapna Patel, Danish Khalid and Valerie Civelli. Audio edition: Suraj Amrutia. Thanks for listening to Rio Bravo qWeek Podcast. If you have any feedback, contact us by email at [email protected], or visit our website riobravofmrp.org/qweek. See you next week!

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Resources: 

Fung, Jason, MD; and Jimmy Moore. “The Complete Guide to Fasting.” Victory Belt Publishing. 2016. p179-189;199-209.