Fasting is often misunderstood, with many believing it slows down the metabolism and leads to fatigue. However, Dr. Jason Fung, a leading advocate of intermittent fasting, reveals that the opposite may be true. In his discussion on the Diary of a CEO podcast, Dr. Fung explains how the activity will impact your body, challenging common assumptions about food and energy levels.1
Fasting Increases Energy, Not Fatigue
Contrary to popular belief, fasting doesn’t slow down your metabolism. Dr. Fung explains that when you stop eating, your body starts to burn stored calories for energy. This process increases your metabolic rate rather than decreasing it. “Your insulin levels drop, and other hormones like growth hormone and cortisol increase, which actually boosts your energy levels,” says Dr. Fung. This goes against the common notion that it may make you sluggish.
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Fasting and the Fight-or-Flight Response
During fasting, the body enters a heightened state of alertness, often referred to as the fight-or-flight response. According to Dr. Fung, “Hungry animals are more dangerous because their bodies are in a state of activation, ready to find food.” This physiological response, driven by increased cortisol and growth hormone, enhances your body’s ability to utilize stored energy efficiently.
Health Benefits Beyond Weight Loss
Research from Cambridge University supports the idea that fasting offers health benefits beyond just weight loss. A 24-hour fast can reduce harmful inflammation in the body by increasing levels of a key fatty acid called arachidonic acid. This has potential implications for lowering the risk of chronic diseases like Alzheimer’s and Parkinson’s.2 “Our work adds to the growing evidence that calorie restriction has broad health benefits,” says Professor Clare Bryant of the University of Cambridge.
Fasting and Brain Health
The benefits of fasting extend to brain health as well. By reducing inflammation and boosting arachidonic acid levels, not eating might help protect against neurodegenerative diseases. However, researchers caution that more studies are needed to confirm these long-term effects. This emerging science suggests that fasting could be a simple way to support cognitive health as you age.
The Breakfast Debate: To Eat or Not to Eat?
While Dr. Fung advocates for fasting, not all experts agree on the benefits of skipping breakfast. Nutrition therapist Justin Nault warns that not eating in the morning could signal metabolic issues. He argues that breakfast helps kickstart metabolism and prevent unhealthy metabolic adaptations. The NHS also advises against skipping breakfast, citing its importance for overall health.
Should You Try Fasting?
