Fad diets rear their disappointing little heads in many forms. From South Beach and Atkins to keto and paleo, it seems like the opportunities to fail at a hard-to-follow, restrictive, and expensive diet are virtually endless. Rather than focusing on the next new diet to try, why not focus on changing up your eating pattern?
It’s a subtle change, but one that makes a huge difference in the scales. Intermittent fasting (or IF) has quickly gained popularity as a highly effective method for weight loss and moderation. We’ve come a long way from the sexy pineapple diet of the 1970s, but what makes intermittent fasting different than any other new weight-loss trend? We figured out the science to give you the skinny on this “new” trend dating back to our hunter-gatherer days.
Intermittent fasting can be done in a variety of ways. Still, each method can ultimately be pared down to one basic rule: all eating and drinking must be done during a specified time frame over a 24-hour period. (This excludes water, black coffee, and plain tea.) Time frames can vary, but the most popular IF methods include:
Regardless of the chosen method, the science remains the same. Enzymes in the gut break down carbohydrates from food and drinks into sugar molecules that can be used by our body’s cells for energy. If these sugars aren’t used, they are stored in the liver as glycogen. Leftover glycogen is then converted into fat, which turns into the squishy bits on our tums and bums we’re so often trying to flatten and firm.
Intermittent fasting forces the body to turn to stored fat cells for energy as opposed to running on a continuous supply of calories from meals, drinks, and snacks in between. Simply put, depleted fat stores = weight loss.
In a word, yes, intermittent fasting is completely safe when done correctly. In fact, humans are evolutionarily designed to survive small periods of fasting. Hunter-gatherers didn’t always have consistent access to food. To withstand not-so-fruitful hunts and harvests, the body learned how to utilize stored fat cells for energy.
(It’s important to note that the human body is only meant to withstand small periods of fasting. Starving the body of nutrients over a prolonged period of time can actually cause fat storage to increase, so be sure to keep the “intermittent” in intermittent fasting.)
Additionally, the human body needs to be in the right rhythm. Circadian rhythms dictate many of our bodies’ processes over a 24-hour period, including sleep, food absorption, and energy storage. For example, roughly 45 minutes after waking up, the “stress” hormone cortisol spikes, impeding glucose regulation. Eating too early during this spike can overwhelm the pancreas, which is responsible for maintaining healthy blood sugar levels, causing an increase in fat storage due to an inability to process the carbohydrates from your breakfast properly.
Eating too late can also cause a dropped beat or two. Melatonin is released approximately two to three hours before the body’s internal bedtime, preparing the pancreas (and the rest of the body) for sleep. Late-night snacks or drinks can’t be properly processed by a sleepy pancreas, which leads to — you guessed it — fat storage and weight gain.
While the research on the long-term benefits of intermittent fasting is fairly young, preliminary findings suggest time-restricted eating does far more than lower the number on the scale. Potential health benefits of IF include:
The best part about intermittent fasting is how easy it is. Embarking on a new diet can often mean investing money into online programs, monthly subscriptions, expensive groceries, or a pricey combination of the three. Intermittent fasting’s greatest quality is its accessibility: all that’s required to adopt this routine is the ability to tell time.
Generally speaking, it doesn’t matter what you eat when you’re intermittently fasting, only when you eat it. A fasting period should be just that: a fast. Even a small splash of creamer in a morning cup of coffee can switch the body’s metabolic processes from drawing energy from fat to drawing energy from sugar. Water, black coffee, or plain tea should be all that’s consumed during a fasting period. During an eating period, there are far fewer regulations (which makes this food regimen so appealing to so many).
Having said that, practicality and moderation are important. Binging on processed foods, alcohol, and sugar for eight hours a day will not offer the same results as a time-restricted diet of whole grains, fruit, vegetables, lean protein, and healthy fats, also known as the Mediterranean diet. No amount of dieting, time-restricted or otherwise, can overcome improper nutrition.
But to err is human, and to give in to a salty or sweet craving every now and then is divine. There are no “bad” foods in this diet, only foods that are poorly-timed or overly-consumed. Intermittent fasting allows you to approach a diet as something to sustain, nurture, and restore the body, not something to control and restrict out of fear, guilt, or shame.
Everybody is different, and every body reacts differently to time-restricted eating. Those who are underweight or have previously suffered from an eating disorder should contact a physician before starting an IF regimen and should only continue under close supervision. Individuals with diabetes, problems with regulating blood sugar or blood pressure, or those taking certain prescription medications should also consult their doctor before fasting.
There is little research on how IF affects male humans as opposed to females, but a 2007 study conducted on rats showed a time-restricted diet had the potential to produce more adverse effects in a female as opposed to her male counterpart, including emaciation, masculinization, infertility, and amenorrhea, or a stop in menstruation. So far, similar effects on female humans are rare and anecdotal.
Therefore, women should approach intermittent fasting mildly. Easing into a time-restricted diet can help monitor any potential adverse reactions and help the body more safely acclimate to a new routine. If you are pregnant, breastfeeding, struggling with fertility, or trying to conceive, consider waiting to adopt an IF regimen. Stop fasting immediately and consult your physician if you experience loss of your menstrual cycle.
Ultimately, intermittent fasting is a safe and effective way of losing weight and improving your overall health for the long haul. Intermittent fasting offers a less restricted and easier-to-follow alternative to the dreaded fad diet and keeps you in tune with your body's natural processes. Of course, as with any major changes in your day-to-day routine, it’s absolutely critical to be safe, be smart, and always listen to your body.