Intermittent fasting isn't a regimen built around limiting calories (although it's likely that your calorie intake will be restricted naturally since you're going a period of time without eating), but it can promote weight loss in a big way. Fasting gives your metabolism an overhaul. It works on the same principles as a ketogenic diet. By restricting food (and carbohydrates), you'll switch your body from burning glucose for energy to burning stored body fat.
Intermittent fasting (intermittent energy restriction or intermittent calorie restriction) is an umbrella term for various eating diet plans that cycle between a period of fasting and non-fasting over a defined period. Intermittent fasting is under preliminary research to assess if it can produce weight loss comparable to long-term calorie restriction.
With all of these drawbacks, you may be wondering: could you (and would you still want to) practice intermittent fasting as a female? If you take a more relaxed approach, the answer is yes. When done within a briefer timeframe, intermittent fasting may still help you reach your weight loss goals and provide the other benefits previously mentioned, without messing up your hormones.
Third, you've probably already fasted many times, even though you don't know it. Have you ever slept in late on the weekends and then had a late brunch? Some people do this every weekend. In situations like these, we often eat dinner the night before and then don't eat until 11am or noon or even later. There's your 16–hour fast and you didn't even think about it.
And while this may sound difficult, it’s really not. After all, the reasons our bodies store fat in the first place is because we, as a species, aren't really designed for constant eating. The three-square-meals (or more) eating plan is a relatively new phenomenon in human history; for much of our past, feast and famine were the order of the day. Our bodies know how to handle long stretches without food, and they know how to make good use of the “feasts” when they come along.
Many people achieve the best results by starting the ketogenic diet first and then beginning intermittent fasting several weeks later. Although this is a bit different from the classic approach to the keto-intermittent fasting diet, it works better for some individuals. This is because intermittent fasting, as previously mentioned, should be a natural process, during which you should not feel deprived and hungry.
If you're looking to lose weight, this isn't a problem. And even if you're happy with your weight, this won't prove to be too much of an issue if you follow the daily fasting or weekly fasting schedules. However, if you're fasting for 24 hours per day on multiple days per week, then it's going to be very difficult to eat enough of your feast days to make up for that.
As with any diet, you’ll get the best results if you’re consistent. At the same time, you can certainly give yourself a break from this kind of eating schedule on special occasions. You should experiment to figure out which kind of intermittent fasting works the best for you. Lots of people ease themselves into IF with the 12-12 plan, and then they progress to 16-8. After that, you should try to stick to that plan as much as possible.
Tons of celebs are jumping on the intermittent fasting keto bandwagon, and for good reason. The two work hand in hand to accelerate weight loss, not to mention stimulate lots of other performance-boosting benefits. Fasting is an extraordinary tool for improving your biology. It’s free. It’s universally accessible. It’s adaptable. It’s the reason it’s always been a major part of the Bulletproof Diet.
Initial human studies that compared fasting every other day to eating less every day showed that both worked about equally for weight loss, though people struggled with the fasting days. So I had written off IF as no better or worse than simply eating less, only far more uncomfortable. My advice was to just stick with the sensible, plant-based, Mediterranean-style diet.
Intermittent fasting is using the same reasoning – instead of using the fats we are eating to gain energy, we are using our stored fat. That being said, you might think it’s great – you can just fast and lose more weight. You have to take into account that later on, you will need to eat extra fat in order to hit your daily macros (the most important thing). If you’re overeating on fats here, you will store the excess.
This is probably a good time to mention that while I have practiced intermittent fasting consistently for the last year, I'm not fanatical about my diet. I work on building healthy habits that guide my behavior 90% of the time, so that I can do whatever I feel like during the other 10%. If I come over to your house to watch the football game and we order pizza at 11pm, guess what? I don't care that it's outside my feeding period, I'm eating it.
Cons: On the flip side, if you have a hard time handling cheat days the healthy way, this method might not be for you. Additionally, because the plan is pretty specific and the fasting/feeding schedule varies from day to day, this method can be a bit confusing to follow. (However, the plan does come with a calendar, noting how to fast and exercise each day, which may make it easier.)
Pros: While 24 hours may seem like a long time to go without food, the good news is that this program is flexible. You don’t have to go all-or-nothing at the beginning. Go as long as you can without food the first day and gradually increase fasting phase over time to help your body adjust. Pilon suggests starting the fast when you are busy, and on a day where you have no eating obligations (like a work lunch or happy hour).
You’ll spike your blood sugar when you eat. If you’re fasting on a high-carb diet and you’ve powered through the cravings and lack of energy from low blood sugar, there’s a good chance you’ll eat a ton of carbs when you feast. You want to eat big meals when you fast to make sure you’re getting enough calories, but all those excess carbs in one go will spike your blood sugar in the opposite direction, from low to high. High blood sugar causes fatigue and lack of focus. That raging hunger will also cause you to binge unnecessarily, and whatever carbs you don’t use will get stored as fat.
This fasting process will not only activate autophagy in your cells, it will also increase your ketones much more quickly than if you were just eating a standard ketogenic diet. If you start implementing intermittent fasting and activities (like walking, cycling, or lifting weights) together, you can raise ketone levels and increase autophagy more than you would with intermittent fasting alone. This suggests that intermittent fasting would be a great addition to your life, but it is important to be familiar with the negative symptoms that can arise before you start.
Zero-calorie beverages are okay. I drink green tea in the morning for my caffeine kick while writing. If you want to drink water, black coffee, or tea during your fasted period, that’s okay. Remember, don’t overthink it – keep things simple! Dr. Rhonda Patrick over at FoundMyFitness believes that a fast should stop at the first consumption of anything other than water, so experiment yourself and see how your body responds.
Conversely, a 2013 study completed by researchers at Washington University School of Medicine, presented the exact opposite, showing increased reactions in receptors on the tongue, when participants were given artificial sweeteners. Their study concluded that if the receptors are capable of detecting sweetness, even though calories aren’t present, a hormonal response (insulin release) is likely.
Surprisingly, since I've started intermittent fasting I've increased muscle mass (up 10 pounds from 205 to 215), decreased body fat (down 3% from 14% to 11%), increased explosiveness (set a personal best with a clean and jerk of 253 pounds a few months back), and decreased the amount of time I've spent training (down from 7.5 hours per week to 2.5 hours per week).
The biggest concern most people have is that Intermittent Fasting will lead to lower energy, focus, and the “holy crap I am hungry” feeling during the fasting period and ruin them. People are concerned that they will spend all morning being miserable because they haven’t consumed any food, and thus will be miserable at work and ineffective at whatever task it is they are working on.