Well, most notably, it’s a great way to get lean without going on a crazy diet or cutting your calories down to nothing. In fact, most of the time you'll try to keep your calories the same when you start intermittent fasting. (Most people eat bigger meals during a shorter time frame.) Additionally, intermittent fasting is a good way to keep muscle mass on while getting lean.
Another perk? There are no “forbidden foods,” and no counting calories, weighing food or restricting your diet, which makes it a bit easier to follow. That said, this isn’t a free-for-all. “You still have to eat like a grown-up,” Pilon says. It’s all about moderation: You can still eat whatever you want, but maybe not as much of it. (A slice of birthday cake is OK, he says, but the whole cake isn’t.)
As a lifestyle-leaning research doctor, I needed to understand the science. The Obesity Code seemed the most evidence-based summary resource, and I loved it. Fung successfully combines plenty of research, his clinical experience, and sensible nutrition advice, and also addresses the socioeconomic forces conspiring to make us fat. He is very clear that we should eat more fruits and veggies, fiber, healthy protein, and fats, and avoid sugar, refined grains, processed foods, and for God’s sake, stop snacking. Check, check, check, I agree. The only part that was still questionable in my mind was the intermittent fasting part.
With methods like this, when the contact time between the water and the grounds is longer, a coarser grind is essential. If the grind is too fine, the grounds can get stuck in the filter or even get through the filter causing problems. It can make it harder to press down on the plunger and your coffee can end up with grinds in it. Worst of all, the finer grind means the coffee is left in contact with the water for too long, causing a bitter brew.
If you think you may have a medical emergency, call your healthcare provider or 911 immediately. Any mention of products or services is not meant as a guarantee, endorsement, or recommendation of the products, services, or companies. Reliance on any information provided is solely at your own risk. Please discuss any options with your healthcare provider.

Amy Shah, MD, is double board-certified doctor who received her medical training from Cornell, Harvard and Columbia Universities. She has a thriving medical practice in the Phoenix area, where she sees more than 5,000 patients each year. In 2015, Dr. Shah was named one of the “Top 100 Women in Wellness to Watch” by MindBodyGreen and was a guest on the Dr. Oz show.


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.
Worried about losing muscle if you fast? Maybe this will put your concerns to rest: a single 24-hour fast increased human growth hormone (HGH) by 2000% in men and 1300% in women.[2]  HGH plays an integral role in building muscle. Boosting your levels this high will have huge effect on your physique. Research shows that higher levels of HGH leads to lower levels of body fat, higher lean body mass and improved bone mass.[3]
The thing is that if you want to slim down and get rid of excess pounds, then the fasted state is really the best way to do it. If you keep taking food into your body, insulin levels will remain high, and you will keep burning glucose for fuel instead of burning fat. Of course, to remain in the fasted state, you need to not be in the fed state, and that can be a problem. Starving yourself all of the time isn’t enjoyable, and it’s not healthy. To be blunt about it, your body needs nutrients, it just doesn’t need them all day, every day.

After determining your preferred protocol of intermittent fasting, you should start planning out your diet for the days that you do eat. On a standard keto diet, 75 percent of total calories should come from fat, 20 percent should be from protein and 5 percent should come from carbs. When getting started, however, you can start with a modified keto diet instead, which is often considered more flexible and easy-to-follow. With this diet plan, about 40–60 percent of calories should come from healthy keto fats with 20–30 percent from protein foods and 15–25 percent from carbohydrates.
One potential disadvantage of this schedule is that because you typically cut out a meal or two out of your day, it becomes more difficult to get the same number of calories in during the week. Put simply, it's tough to teach yourself to eat bigger meals on a consistent basis. The result is that many people who try this style of intermittent fasting end up losing weight. That can be a good thing or a bad thing, depending on your goals.
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).
While the idea of fasting can be overwhelming, especially if you haven’t done it before, intermittent fasting can actually be a lot easier than many other types of eating plans. Since you are fasting for time restricted chunks of the day, you’ll be eating less food, which eliminates a lot of the stress around having to meal prep. During the periods of time in which you're eating, you’ll still want to focus mainly on healthy fats, clean protein, and carbohydrates from whole food sources—but this isn’t an excuse to hit the drive-thru and load up on sugar the rest of the time! Here are some of the effects of intermittent fasting:
Crescendo fasting only requires you to fast a few days a week instead of every day. My experience is that women get a lot more benefit from doing it this way without accidentally throwing their hormones into frenzy. This is a more gentle approach that helps the body more easily adapt to fasting. And if women do it right, it can be an amazing way to shave off body fat, improve inflammatory markers and gain energy. (7)

AN IMPORTANT CAVEAT: Intermittent Fasting can be more complex for people who have issues with blood sugar regulation, suffer from hypoglycemia, have diabetes, etc. If you fit into this category, check with your doctor or dietitian before adjusting your eating schedule. It also affects women differently (there’s a whole section dedicated to that below)
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