Is intermittent fasting good for you? How is fasting different from other diets?
Fasting involves consuming only water or zero-calorie drinks for at least eight continuous hours. Whereas other diets result in insulin resistance, fasting has numerous health benefits.
Let’s look at how your body processes food and how intermittent fasting helps your health.
How Your Body Processes Energy
To understand why intermittent fasting is good for you, you need to know how your body processes energy. Mindy Pelz explains that your body converts what you eat into energy in two ways: It either burns sugar in your bloodstream to produce glucose or it burns your fat stores to produce glucose for energy plus ketones as a byproduct. Ketones can serve as an alternative energy source when glucose levels are low.
When you consume food, your blood sugar level increases and your body converts this sugar into glucose for energy. To keep your blood sugar level stable, your body releases insulin, a hormone that exports glucose to your cells and stores the rest in your muscles and liver as an energy reserve. If your body doesn’t use this energy reserve, the insulin converts any excess glucose into fat and stores it away.
After you stop consuming food, your blood sugar level gradually decreases and your body relies on the excess glucose stored in your muscles and liver for energy. Once this excess glucose runs out, you enter a fasted state, during which time your body converts your fat stores into ketones for energy.
| More Detail on How Your Body Converts and Stores Energy In The Obesity Code, Jason Fung explains these processes in more detail. When you eat, your body breaks down each macronutrient—proteins, fats, and carbohydrates—into materials it can use. Carbohydrates are composed of sugar molecules, so they become glucose, a simple sugar that every cell in your body can use for energy. As Pelz says, this rise in blood sugar stimulates the release of insulin. Fung explains that insulin acts like a key, fitting into the insulin receptor on a given cell and “opening the door” for glucose to enter the cell. If there’s more glucose than needed, insulin chains together glucose molecules into glycogen and stores them in the liver. Later, the body breaks glycogen back down into glucose when the body needs more energy. Fung compares glycogen stores and fat stores to your wallet and bank account, respectively. Glycogen is easier to access, but your liver stores a limited amount. Conversely, your fat stores are difficult to access but hold far more potential energy. Fung also explains that your body doesn’t start converting fat stores into ketones until one to three days into a fast. In the first 24 hours, your body instead breaks fat down into glycerol, from which it produces new glucose. |
Typical Diets Deplete Your Health
Typical diets tend to restrict food intake, either by limiting the types of food you eat or the amount of food you consume. However, they often don’t restrict when you consume that food. This lack of restriction results in a tendency to eat continuously.
When you eat without long breaks and prevent your body from entering a fasted state, your body relies solely on glucose for energy. According to Pelz, continuous reliance on glucose can lead to chronically high insulin levels, contributing to insulin resistance.
Insulin resistance is a condition where cells become less responsive to the effects of insulin and can’t efficiently use glucose for energy. This condition diminishes the effectiveness of insulin in regulating blood sugar levels, creates an excess of glucose that your body stores as fat, and disrupts hormonal balance. Pelz argues that these effects lie at the root of numerous health issues, such as obesity, chronic fatigue, high blood pressure, and diabetes.
Fasting Restores Your Health
Pelz suggests that regular fasting restores and optimizes your overall health by improving your immune system, aiding in healthy weight maintenance, and enhancing mental health and cognitive functioning. Let’s explore how fasting contributes to these three effects.
1) Fasting Improves the Immune System
As your body’s primary defense against illnesses, your immune system plays a crucial role in maintaining your overall health. Pelz says that fasting strengthens your immune system by:
Triggering autophagy: Lowering glucose levels forces your body to turn to cellular debris as an alternative energy source. This process, known as autophagy, strengthens cellular health by detoxifying, repairing, and removing damaged components and harmful pathogens. It makes cells more resilient against age-related decline and inhibits viral replication, counteracting degeneration and inflammation that can lead to various health challenges.
Improving gut health: Fasting, by allowing the digestive system to rest, reduces gut inflammation, fostering the ideal environment for beneficial bacteria to thrive and spread. This rest phase also stimulates the growth of gut-healing stem cells. According to Pelz, these processes promote a microbial balance that supports your immune system in multiple ways, including enhancing cellular health and glucose regulation.
2) Fasting Aids in Weight Maintenance
According to Pelz, fasting helps you lose weight or maintain a healthy weight by:
Balancing insulin levels: When you fast, you prompt your body to metabolize its stores of glucose and fat for energy. This stabilizes your blood sugar levels, lowers your insulin production, and helps regulate your weight by preventing excessive fat storage.
Suppressing appetite: Pelz suggests that each time you fast, ketones (chemical byproducts of fat metabolism) inhibit your hunger hormones, making you less inclined to overeat.
Metabolizing stubborn fats: Pelz says that fasting promotes the conversion of stubborn subcutaneous fats into metabolically active fats, which are easier for your body to burn for energy.
Stimulating growth hormone production: Pelz explains that, by decreasing blood sugar levels, fasting triggers a significant increase in hormones that facilitate fat-burning, muscle growth, and a healthy body composition.
3) Fasting Enhances Mental Health and Cognitive Functioning
Pelz argues that fasting improves both your mood and your mental acuity by:
Repairing neurons: Elevated ketone levels during fasting support the regeneration of damaged neurons, enhancing memory, focus, and mental clarity.
Providing consistent energy: Pelz explains that, unlike glucose, ketones offer a stable energy source, preventing fatigue and supporting overall cognitive function. dopamine pathways: Continuous eating elevates your dopamine (a pleasure-related neurochemical) baseline. Over time, this leads to an increased need for food to achieve the same level of pleasure. Pelz suggests that fasting diminishes this dependency and enhances the sensitivity of dopamine receptors, reducing your reliance on food for a sense of well-being.
Calming anxiety: According to Pelz, increased ketone levels trigger the release of GABA, a calming neurotransmitter that promotes relaxation and emotional stability.
