Studies indicate that short-term fasting can increase longevity, help regulate glucose levels, and help treat everything from asthma and autoimmune diseases to cardiac arrhythmia’s. These experts argue that constant grazing can actually disrupt metabolic pathways and that the best way to kick our metabolisms into high gear is to occasionally eat less often — in short, to observe an eating pattern known as intermittent fasting.
When most of us hear the word “fasting,” we’re likely to think of politically motivated hunger strikes or days or months without eating. But the occasional fasting these experts are recommending is something different. They point out that humans evolved through multiple short-term periods of caloric restriction, and that our metabolisms operate more efficiently when freed from the burdens of 24/7 digestion and nutrition assimilation.
The time frames recommended for intermittent fasting vary. Popular options (all of which can incorporate sleep time) include daily 14- to 16-hour fasts, once- or twice-weekly 24-hour fasts, and alternate-day fasts of assorted time durations. While the case for fasting as a general-health tool is compelling, the case for fasting as a longevity booster may be even more compelling. Studies have shown that severely restricting calorie intake can increase the lifespan of rats and mice and increase overall health.
In the study, researchers noted that mice who continually grazed on fatty food for 100 days gained weight and developed high cholesterol, high blood glucose and liver damage. The mice that fasted for 16 hours a day — but ate the same total amount of food during their non-fasting periods — weighed less, stayed healthy and performed better when they exercised.
Why? Researchers have found that after a few hours of fasting, the body starts to burn fat and break down cholesterol into beneficial bile acids. The liver, meanwhile, shuts down glucose production for several hours, lowering blood glucose levels. Instead of ending up in the bloodstream, extra glucose is used to repair damaged cells and make new DNA, which can help prevent chronic inflammation. Meanwhile, liver enzymes are activated and help in the creation of brown fat (the good kind, which converts extra calories to heat).
Getting Started on Your First Fast
Strength and conditioning specialist Mike T. Nelson, who is currently doing doctoral research at the University of Minnesota in kinesiology, has coached many fasting newbies. His advice: Start by just coaxing your body in the right direction. Approach it as an experiment, and don’t get hung up on an iron-clad number of hours you’ll go without eating. “Long-term, it’s ideal to not to over plan your fasts, and to simply listen to your body. If you wake up one day and you’re not feeling hungry, that may be a good time to start a fast,” he says. Here are more of Nelson’s tips.
– Begin by eating an early dinner and just avoiding food for a few hours before going to bed, then push the first meal of your day back by an hour or two.
– Plan a post-fast meal. Include lean meat or fish, a vegetable, and maybe a fruit, but don’t load up on grains and starches and avoid gorging.
– Schedule your fast for a busy day. You’ll benefit from not having to stop to eat food and you’ll be distracted enough by your activities that you’ll be less likely to notice habitual urges to eat.