Intermittent fasting has captivated the interest of health enthusiasts and researchers alike for decades. Unlike traditional diets that dictate what foods to eat, intermittent fasting focuses on when you eat. This method involves cycling between periods of eating and fasting, which can help simplify meal planning and improve your relationship with food.
But does intermittent fasting actually work? Can it truly help you lose weight, improve your gut health, and even boost brain function? This intermittent fasting for beginner’s guide will explore the principles, benefits, and practical tips for incorporating a fasting schedule into your lifestyle. Whether you’re looking to shed a few pounds, enhance your energy levels, or embark on a path toward better overall health, this guide has all the essential knowledge you need to get started with intermittent fasting.
What is Intermittent Fasting?
Intermittent fasting (or IF for short) is a pattern that cycles between periods of eating and not eating. Where traditional diets focus on calorie restriction, intermittent fasting is about when you eat. This allows for flexibility with different intermittent fasting schedules that can fit various lifestyles.
The origins of fasting stretch back far in history. Humans have fasted for ages, sometimes due to necessity (food scarcity) and other times for religious reasons (such as Ramadan).
How Does Intermittent Fasting Work?
Intermittent fasting affects how your body uses energy by cycling between eating and fasting windows. When you eat regularly, your body uses glucose from carbs as its main fuel source. However, after several hours of fasting or not eating, your glucose levels start to decrease.
Once those stores are depleted and the fast extends, your body dips into fat stores for energy through ketosis. This process produces ketones, an alternative fuel source that some cells, especially in the brain, can use. This metabolic switch is a key factor in the potential benefits of intermittent fasting, such as energy and focus.
Benefits of Intermittent Fasting
The benefits of fasting can be traced back as far as the 5th century from the “father of medicine”, Hippocrates. As a doctor, he recommended his patients abstain from food or drink for certain illnesses. Even the great philosophers Plato and Aristotle supported fasting to improve physical well-being and mental clarity.
In the 20th century, research on the health benefits of fasting, especially for weight loss, gained traction and increased interest in the approach greatly. Today, medical professionals continue to explore other benefits of intermittent fasting, and what they’ve discovered has been quite promising:
- Promotes Weight Loss
- Improves Glycemic Control
- Cellular Repair and Better Gut Health
- Reduces Inflammation
- Promotes Neurogenesis
1. Promotes Weight Loss
One of the most well-known benefits of intermittent fasting is losing weight. By simply using fasting windows to restrict your caloric intake, you’ll naturally consume less calories overall. Furthermore, research has shown that IF can influence the hormones that regulate weight such as insulin (promotes fat storage) and leptin (gives signals that make you feel full). When your insulin levels drop it can potentially burn fat and cause leptin levels to rise, making you feel satisfied and eat less.
2. Improves Glycemic Control
When it comes to managing blood sugar levels, studies suggest intermittent fasting can help improve the body’s ability to use insulin effectively. This can lead to lower blood sugar levels, potentially benefiting those with type 2 diabetes or prediabetes.
3. Cellular Repair and Better Gut Health
Some research on IF has found that it can trigger cellular repair mechanisms and positively influence the gut microbiome. A recent study examined how fasting affects the gut microbiome using research from both animal and human studies. Most studies showed positive effects of fasting on the types and overall balance of gut bacteria — especially with increases of Lactobacillus and Bifidobacteria — as well as increased production of short-chain fatty acids.
However, it's important to note that a few things can influence the efficacy of this benefit. For example, how long someone fasts, if they have any health conditions (like obesity), and even if they're fasting for Ramadan all impact the diversity of bacteria in the intestinal microbiome.
4. Reduces Inflammation
Chronic inflammation is linked to various health problems like arthritis. However, some research suggests that intermittent fasting may reduce inflammation through decreased systemic and adipose tissue inflammation, improved metabolic health, and enhanced antioxidant responses. One study in particular monitored over 100 volunteers celebrating Ramadan and found that prolonged intermittent fasting did have a positive effect on the inflammatory response of the body!
5. Promotes Neurogenesis
While the research is still in its early stages, some studies on animals have shown that intermittent fasting may stimulate the growth of new neurons and brain cells, particularly in the hippocampus. This can potentially improve cognitive function along with memory in humans.
There are also studies exploring the potential role of IF in preventing neurodegenerative diseases like Alzheimer's due to reductions in β-amyloid levels. However, the evidence is not entirely consistent, and further research, particularly long-term human studies, is needed to establish its efficacy and guidelines for its application.
Important Intermittent Fasting Rules
As we mentioned earlier, unlike traditional diets that focus on what you eat, intermittent fasting is a schedule of when you eat. There are no hard rules, but here are a few concepts to keep in mind before you choose a fasting schedule:
- For beginners especially, consider starting your fast after dinner so a large portion of the fasting period occurs when you’re sleeping.
- Most importantly, listen to your body and adjust fasting periods based on your body’s responses and health needs.
- While you’re abstaining from consuming calories during your fasting period, there are exceptions to help keep you hydrated such as water, black coffee, or tea.
- During your eating windows, make sure you focus on balanced, nutritious meals instead of junk or overly-processed foods.
- Stay active and keep your mind engaged during fasting windows so you’re not thinking about food and hunger.
- Finally, if you have underlying health conditions or take prescription medicines, it’s advisable to first talk with your doctor before beginning any fasting routine.
Types of Intermittent Fasting Schedules
There are several different intermittent fasting schedules, each with its own approach to fasting and eating windows. As you begin fasting, it’s important to choose a method that best fits your lifestyle and preferences. Here's a breakdown of the most popular ones:
16/8:
This is one of the most popular fasting schedules and involves fasting for 16 hours with an eight-hour window for eating. This time frame allows for a late breakfast (around 10am or 11am), lunch around noon, and an early dinner before 6pm.
14/10:
Similar to the above, this method involves a shorter fast (14 hours) but a longer eating window (10 hours), making it a great option for beginners. It’s not a huge change in schedule to eat your meals between 8am and 6pm, so it’s a strong starting point for those interested in IF.
Eat Stop Eat:
Created by Brad Pilon, this schedule involves a 24-hour fast once or twice a week. You can choose any non-consecutive period that works for you as long as you don't consume any calories during those 24 hours.
5:2 Diet:
Similarly, this approach involves eating normally for five days and then restricting intake to 500-600 calories on the remaining two (non-consecutive) days.
Alternate-Day Fasting:
Being one of the more intense schedules, this one involves fasting every other day for a full 24-hour fasting period.
Warrior Diet:
This is a relatively difficult method that involves very little consumption (mostly fruits and vegetables) during a 20-hour fasting window. You then have a large meal within a short 4-hour eating window at night.
Intermittent Fasting FAQs
What is the Best Way to Start Intermittent Fasting?
With all the different schedules it can feel overwhelming to start intermittent fasting. Our advice is to start slow (like with the 14/10 schedule) and find what fits your lifestyle best. For example, you could see how you feel after skipping breakfast and pushing lunch to the mid-afternoon. Remember, there’s no pressure to jump right to the more intense schedules such as alternate-day fasting.
How Long Does it Take to See Results From Intermittent Fasting?
Some people experience the benefits of intermittent fasting right away, but noticeable results on the scale can take time. Typically, it takes about two to four weeks for your body to adjust to a new eating pattern. So, during this time, don’t feel discouraged if the weight loss isn’t happening. If you feel less bloated or like you have more energy, these can be great signs that fasting is working for you. Most importantly, stay consistent with your fasting windows and focus on healthy foods during your eating periods.
Can You Get in a Sauna While Fasting?
Using a sauna while fasting is generally safe, but there are some considerations to keep in mind. First, drink plenty of water to stay hydrated, as saunas can cause significant sweating. You might even want to consider replenishing your electrolytes with a low-calorie sports drink or electrolyte tablets after your sauna session. Secondly, keep your sessions shorter, around 10-15 minutes, and remember to listen to your body. It's best to end your session and cool down if you begin to feel dizzy, lightheaded, or nauseous (all of which are symptoms that can be intensified when fasting).
Can You Take a Cold Plunge While Fasting?
Louisa Nicola, MMed, BSc says "While further research is necessary, combining cold plunges with fasting might enhance focus. Cold water immersion can elevate alertness hormones such as adrenaline, noradrenaline, and dopamine, similar to the effects of fasting. However, cold exposure can influence blood sugar levels, so individuals with diabetes or blood sugar concerns should exercise caution when fasting."
Cold plunging while fasting can be done safely and can even be a great addition to your morning routine, as the two have the potential to work together for greater benefits. While more research is needed, cold plunges and fasting together may potentially improve your focus. Cold water might increase alertness hormones like adrenaline, noradrenaline, and dopamine, which fasting can also slightly elevate. This could be good for focus. However, cold exposure might also impact blood sugar, so people with diabetes or blood sugar problems should be extra cautious while fasting.
Final Thoughts on Intermittent Fasting
As you can see, intermittent fasting is more than just a trend — it's a flexible approach to eating that can offer numerous health benefits. Remember, there's no one-size-fits-all approach to IF. The key is to find a method that integrates seamlessly into your lifestyle and wellness journey.
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