Should you fast intermittently during the winter?

Intermittent fasting is a hotly debated topic. Some athletes embrace it as part of their training. Others say that by not eating in the morning, you’ll feel more focused as your body isn’t spending energy digesting a heavy breakfast. On the other hand, there are experts who say that intermittent fasting is overhyped and dangerous.

The concept is relatively simple. The most common approach discards the old adage “breakfast is the most important meal” by completely skipping it. Your last meal can be at 8 p.m., and your next not until noon. The magic ratio that many use is 16:8. That means 16 hours with no calories–only black coffee, tea or water, and then eight hours where you would eat normally. It doesn’t mean that you should overeat during those hours; you should still eat a healthy diet.

The way it is said to work is when your body uses all its glycogen, it will then target your fat stores. Think of glycogen as whatever cash you have in your wallet, and fat storage is your savings account. After 12 hours you will exhaust all your glycogen, and then your body will dine on your fat.

Many athletes and celebrities swear by the approach, saying it’s the easiest diet they’ve ever tried. Hugh Jackman, (a.k.a. Wolverine) said he used intermittent fasting to get ripped. Others hate it, saying they get hangry and unable to exercise. The Internet is full of conflicting studies. (Go figure.) The proponents of intermittent fasting list a wide range of benefits, over and above fat loss. Some studies have shown that intermittent fasting boosts your memory, improves blood pressure, and accelerates tissue repair.

On the other hand, there are studies that suggest intermittent fasting can disrupt your sleep by decreasing the length of REM sleep, or worse, cause an irregular heartbeat. There’s even some that claim that intermittent fasting can cause you to feel lonely as you’re not eating with people as much.

If you are a fan of fasting, and it works for you, there may be one concern if you’re riding outside in rain or snow in the winter: some experts suggest that riding on an empty stomach can negatively affect your immune system. In a study conducted by the University of  Southern California, there was concern that fasting can ultimately compromise your immune system. It might be even particularly important nowadays to have a strong immune system given that particular virus floating around. (If you’ve just arrived from a two-year trip to Jupiter, I am referring to COVID19.)

Ultimately whether you fast or not is a personal choice, but there are certain people who are discouraged from it. If you’re pregnant, or under 18, it’s not a great idea to fast intermittently.