Humans have fasted throughout history for many reasons: religious beliefs, medical help and a simple shortage of food. Today intermittent fasting has been brought to the top of the news for another reason: weight loss. Proponents say that highly reducing one’s food intake on certain days can reduce weight, improve your metabolism and perhaps even give you a longer life. Could intermittent fasting be right for you?
First of all, before you start any kind of diet or make a massive change to the way you eat, you should consult your medical professional. And if you’re the type of person who gets crabby if they don’t eat every four hours, intermittent fasting is probably not for you.
What is intermittent fasting (or IF)? It’s basically an eating schedule that alternates between periods of normal eating, and periods of time where one’s caloric intake is highly restricted. You eat regularly for a while, and then you subsist on very low-calories drinks or foods, such as black coffee or green tea. There are a few different types of fasting:
- The most common type of fasting is called Alternate Day Fasting (ADF) or Every Other Day Fasting (EOD). You eat whatever you want one day (24 hours), then follow a very restricted diet the next day (24 hours). Experts recommend 500 calories for women and 600 calories for men during the fasting day to see results.
- Another version of intermittent fasting is to eat whatever you want during a certain time window, for example noon to 8PM. Your window of eating time is the same each day, and could span 8 hours, 6 hours or even 4 hours.
- You can also just skip a meal or two on certain days of the week.
- The “Master Cleanse” fast (featuring cayenne, lemon juice and maple syrup) and other periodic multi-day fasts are also considered intermittent.
Proponents of intermittent fasting argue that our human ancestors likely fasted throughout their lives. Hunters and gatherers don’t always have continuous access to the same kind of food, and therefore the human body evolved to be fast-friendly. Our ancestors certainly didn’t sit down every day for three solid meals.
Fasting may reduce risk factors for certain chronic diseases; for example it seems to reduce the risk for coronary artery disease by lowering triglyceride levels. It may also help protect against cancer, diabetes and of course, obesity.
Some evidence suggests that IF benefits the health and longevity of humans and other animals. Reducing the calorie consumption of rodents, fruit flies and nematodes by 30-40 percent increased their life span by one-third.
Does the same apply to humans? The verdict is still out, and caution is advised. People may be tempted to overeat on their non-fasting days, or eat fattening, non-healthy food. Longer fasts may stress the body, and might not be appropriate for people who are already under a great deal of stress. And fasting might not work well for athletes who lead a very active lifestyle.
Still, intermittent fasting is an interesting idea and worth a try for those wishing to lose weight – and those with willpower.
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