Intermittent Fasting - A Tool for Sustainable Weight Loss - Part 2: How It Works
As discussed in Part 1 of this series on intermittent fasting, many popular approaches to weight loss, including low-fat and calorie-restricting diets, often don’t lead to sustainable weight loss. According to researchers at UCLA, “You can initially lose 5 to 10 percent of your weight on any number of diets, but then the weight comes back...Sustained weight loss was found only in a small minority of participants, while complete weight regain was found in the majority. Diets do not lead to sustained weight loss or health benefits for the majority of people.” Depressing news - especially considering the amount of time and money, people sink into trying to take off the pounds.
In this blog, we are going to evaluate intermittent fasting as a tool to help people achieve more sustainable weight loss results.
HOW DOES INTERMITTENT FASTING WORK?
In his long-overdue book The Obesity Code, Dr. Jason Fung writes, “Weight gain and obesity are driven by hormones - and only by understanding the effects of insulin and insulin resistance can we achieve lasting weight loss.”
The Two-Compartment System - An Analogy for Understanding How Fasting Works
Our body can derive energy from two main sources - glycogen (aka glucose) that is stored in the liver, or from stored fat (think belly fat and fat around the organs). For this analogy, we want you to think about glycogen in the liver as a refrigerator and the stored fat around the belly and other places in the body as the freezer.
Food in the fridge is easy to put in and take out - so glycogen stored in the liver is the first thing your body reaches for. Conversely, imagine that food in the freezer way down in your basement is harder to get to - so stored fat is more difficult to access. And we don’t access it until after the refrigerator is empty.
The Recipe for Weight Loss
To access stored fat, one must empty the refrigerator (i.e. the liver) to be able to access the freezer (stored fat). We empty the refrigerator and access the freezer by exposing ourselves to less insulin less frequently. Insulin is the blood sugar regulator, signaling the body to store extra energy (i.e. glycogen) in the liver - i.e. put more food in the fridge. Every time we eat, especially excess calories and high-carb foods, insulin drives glycogen into the liver. When the liver becomes full, overflow glycogen is stored as fat (i.e. in the freezer). In simple terms, too much insulin too often will cause your refrigerator to overflow - forcing the body to store fat in the freezer (aka weight gain).
Emptying the refrigerator can be done by reducing calories and reducing the frequency with which you are exposed to insulin. While reducing calories can help you empty the refrigerator, reducing your exposure to insulin via intermittent fasting makes this process more efficient. This is because insulin inhibits lipolysis (breaking down stored fat for energy). In other words, frequent exposure to insulin (i.e. constant snacking) slows down the fat-burning process. Conversely, weight gain happens when that refrigerator is full - we fill the refrigerator with food every time we eat, and frequent meals or eating foods that spike insulin accelerate this process. Think bagels, rice, tropical fruits, pasta, muffins, etc. - even with limited calories these high-carb foods lead to insulin resistance and metabolic dysfunction.
Dr. Fung suggests that the hormonal imbalances that plague so many of us are a result of our eating choices - such as frequent snacking and consuming processed foods, refined carbs, and the ubiquitous added sugars. Remember, insulin resistance is a metabolic problem that underlies many of our weight issues.
WHAT DOES THE RESEARCH SAY?
The Harvard Public School of Health published a Diet Review of Intermittent Fasting, stating that a “systematic review of 40 studies found that intermittent fasting was effective for weight loss.” Additionally, a study published by the U.S. National Library of Medicine states, “an intermittent fasting diet may provide a significant metabolic benefit by improving glycemic control (and) insulin resistance … with a reduction of BMI in adults.”
According to a June 2022 study in the Clinical Nutrition Journal, a group of 28 obese adults completed a 12-week weight program. Both groups were given the same amount of calories, but one group was given small meals throughout the day (continuous calories) while the other group was put on intermittent energy restriction (i.e. intermittent fasting). While both groups lost weight, the intermittent fasting group experienced improvements in insulin resistance and inflammatory markers that the continuous calorie group did not experience. In other words, fasting but not a low-calorie diet improves metabolic health - an important root cause of weight gain, inflammation, and disease.
INTERMITTENT FASTING DEFINED
Whereas calorie restriction is a consistent pattern of reducing your average daily caloric intake, fasting regimens focus primarily on your eating frequency. I recommend that my patients take a two-pronged approach: focus on “time-restricted feeding” whereby you consume your meal within sixty minutes when possible; and, adopt an intermittent fasting protocol that is right for you. There are a variety of intermittent fasting approaches:
For beginners, I recommend a 16:8 protocol - which means eating two meals per day within eight hours. The most common version is skipping breakfast, and then eating lunch and dinner in eight hours.
Another option once you’re familiar with fasting is the one meal a day (OMAD) plan. Once you’re comfortable with 16:8 most days of the week - you can try integrating 2-3 days a week of OMAD. For instance, eat a normal dinner on a Monday, skip breakfast and lunch on Tuesday, and then have dinner on Tuesday night. Even if you’re not perfect with your 16:8 protocols on most days - incorporating OMAD up to three days a week shows benefits to metabolic function, insulin resistance, and weight loss. This is also known as the 24-hour fast.
You can also try alternate-day fasting where no food is consumed every other day and then eating is unrestricted on the days in between. Another way to look at this is not eating for 36 hours.
The 5:2 eating pattern allows for unrestricted eating for five straight days each week, followed by two days of fasting. This is the 48-hour fast.
This website features some great examples of sample meal plans for 24- and 36-hour fasting protocols (as well as printable PDFs).
INTERMITTENT FASTING - TIPS & TRICKS
Let’s be honest - fasting isn’t a walk in the park. But it’s like a muscle - the more you train it, the stronger it becomes. To ensure my clients find success, I like to share some tips and tricks - to provide “training wheels” while you develop your fasting muscle to become stronger. Here are some of my favorites:
Coffee and tea are allowed - drink up.
Full-fat, unsweetened dairy or milk alternatives - coconut milk*, nut milk, or organic Half & Half are optimal (1-2 tablespoons in coffee or tea) (*I highly recommend organic, full-fat, canned coconut milk.)
MCT Oil (Medium Chain Triglyceride oil) - during fasting our body can utilize MCT as a very quick energy source while maintaining our fasting state. MCT oil can help maintain a fat-burning state called ketosis. You can have unlimited amounts of MCT - however, it can cause stomach upset or loose stool in large amounts if you don’t ramp up slowly.
Bone Broth - when patients are learning how to fast - bone broth can keep energy levels up and hunger at bay. As patients become more adept at fasting, they often find omitting bone broth from fasting brings about optimal results.
A pinch of salt - maintaining electrolyte balance is important during fasting, so a pinch of sea salt washed down with some water a few times a day can help maintain energy levels and electrolyte balance.
Magnesium - patients can be at a slight risk of magnesium deficiency during fasting. Additionally, insomnia can be a side-effect of fasting - and magnesium can have a calming effect that addresses sleep challenges. Magnesium also helps treat constipation.
Fiber - psyllium husk or prebiotic powders can help ensure regular bowel movements - as well as help with satiety.
Breaking your fast - when you break a fast, it is really important to focus on eating nutrient-dense, high-quality foods. This means high-fiber green vegetables, grass-fed meats and wild-caught seafood, organic eggs, and healthy fats such as olive oil, avocado oil, avocados, olives, seeds, and nuts (see Resources list at the end of this blog). One additional tip to consider is eating order - studies show that when people ate protein, fat, or high-fiber vegetables 10-15 minutes before carbohydrates or high-sugar items like fruit, it buffered the glycemic effect and improved satiation.
I have incorporated fasting into my daily routine, and find it makes me feel mentally clear and energized. I try 16:8 most days - and rarely waver on work days. I also incorporate a 24-hour fast once a week.
SO WHAT DOES THIS ALL MEAN?
I believe an intermittent fasting regimen can be a powerful tool for those looking to lose weight - and keep it off. That said, I understand it can sound daunting. When I first introduce the concept, many of my patients cringe - imagining I’m asking them to starve themselves. I get it. But just remember, fasting is like a muscle. The more you exercise it - the stronger it gets. And one other thing to remember - we did not evolve to eat every two hours. In the next part of this blog series - we address several concerns that may arise around intermittent fasting.
Before embarking on a fasting regimen, please keep in mind that it’s important to consult a physician to determine the best approach to meet your specific goals and needs - as well as ensure you are consuming a healthy diet alongside your intermittent fasting protocol. Interested in being a patient? Check out our own Medical Weight Loss program - or give the office a call at 425-970-8568.
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