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5:2 Intermittent Fattening

A food lover's version of the 5:2 Intermittent Fasting diet.

TLDR: Twice a week, for two 36 hour periods, consume no more than 600 calories with at least one day of normal eating between the fasting periods. There are no other restrictions.

"Your body is not a temple, it's an amusement park. Enjoy the ride."

Anthony Bourdain

5:2 Intermittent Fattening is a fasting "diet" almost identical to 5:2 Intermittent Fasting (IF) popularized by former doctor and BBC journalist Michael Mosley in the UK. The principle difference is that rather than some long term goal of better health or longer living, Intermittent Fattening is designed so that one can eat exuberantly and not keel over in the short term, and also so that one can continue to fit into one's clothes.

The regimen allows 5 days of "normal" eating interspersed with two 36 hour periods of strict caloric restriction. The two fasting days should be separated by at least one day of normal eating. Let's get this out of the way: the math doesn't really add up as the "2" in 5:2 is actually 72 hours in total, not 48. You'll get over it. Especially because you will be asleep for a fair amount of the time.


Let's also get the requisite disclaimers out of the way: I am not a doctor, medical professional, dietitian, or even a chiropractor. I am a food writer specializing in meat and eating aesthetically rather than nutritionally. The information here is largely anecdotal, and you should consult a doctor before engaging in a fasting diet, even though I didn't. With that indemnity out of the way, let's proceed.

I put the term diet in quotation marks above because I think that lifestyle is a more appropriate term. 5:2 doesn't change what you eat, just when you do it; further more, it is something that I have adopted on a permanent basis since 2015; and I think you might too. As a food writer with a career stretching back a decade and a half, it wasn't just time that stretched. Despite being quite active I ballooned up to 235lbs through a steady diet of weekly restaurant, pizza and hamburger reviews. Approaching 50 at the time I needed to make some changes before I had to replace my wardrobe entirely and up my health insurance premium. While I wasn't suffering from any health issues the writing was on the wall. I had lost several friends and colleges in the industry due to poor health. While I had previously effectively lost weight using low carbohydrate dieting the thought of restricting what I ate wasn't just unappealing, it was professionally impossible.

My view of the human diet is that scientists probably know about 10% of what we need to understand about nutrition, and that I know far less than 10% of that. But on an individual level that shouldn't matter, as long as one understands their own needs and what they want out of life. Speaking from personal experience I have found the human stomach to be a vat of acid that will accept pretty much anything that modern life throws at it. I am fortunate that I don't suffer from food allergies, although I have a profound and deep seated mistrust of vegetables.

There is no universal nutritional profile that suits everyone, we all have differing needs and as a benefit of living in the age of abundance, an almost absurd amount of choice as to what we eat. I know strict meat-only carnivores in their 50's with bodies of a Greek Adonis, and vegans who do Iron Man competitions. Even those with ghastly diets can hang on for years, putting quality of life issues aside. The beauty of 5:2 is that it is diet agnostic. No matter what you regularly consume, you just need to stop doing it for a few hours a week. It's a diet so simple that you only require a clock to follow it.


While we may be designed to be able to draw nutrition from a vast array of foods I don't think we are necessarily designed to consume them with the regularity of modern life. Three meals a day, everyday is just not something that we see either in nature, or historically in human society. By just not eating you allow your body to worry about other things than digestion. As an added benefit, you'll start burning fat for fuel.

How to Eat

The most challenging part of using this method of fasting, beyond the gnawing hunger you might experience, is that you need to figure out the correct amount of calories to consume on the fasting days. It's easy to over consume, counting calories under the best circumstances is notoriously difficult, all the more so when you are seemingly starving. To that end the internet and a food scale can be useful, as can apps such as Lose It that can give you calorie counts and also track calories.

In terms of tracking the fasting period you only need to remember what time you had your final full meal on the day before the fasting period and add 36 hours to that. So if you are fasting on Wednesday, and you finished dinner at 8PM Tuesday, you can resume eating normally at 8AM on Thursday. You can set a watch reminder, or even use apps such as Zero.

Fair Warning

Be warned: discomfort is part of this diet, your tolerance for it will vary but will get easier over time. That said, fasting isn't for everyone. I happen to be stocky and physically robust, I can go long periods without food, don't get light headed or have issues with blood sugar. I am ideally suited to fasting. Another note: women are restricted to 500 calories while men get 600. Don't blame me, I didn't write the rules.

What and When to Eat

Frankly, I don't think it ultimately matters what you eat during the fasting period -- low carb, high carb, gluten free, vegan etc. But eating foods that will give you energy over a sustained period of time such as fats, protein or complex carbohydrates will serve you better that slurping down a bunch of sugary drinks or fast food drek. You want to avoid spikes to your insulin levels as this will lead to a crash, so seek out foods that have a low glycemic index. A low carb diet is actually ideal on fasting days, even if you don't adhere to it the rest of the week.

Make sure you drink plenty of water during the fasting period, you don't want to get dehydrated which can happen during prolonged fasts. You can also drink plain tea and black coffee in fairly large quantities as they have vanishingly low calories - tea is around two calories, a cup of coffee has three. Just remember that if you add sweetener or milk to add the calories to your tab. I find caffeine helps with the hunger pangs that are inevitable. I suppose that you can probably also drink sugar free sodas, but I avoid them like the plague for aesthetic reasons.

A Shack Shack burger. Not an ideal 500 calories but delicious!

Your biggest decision beyond what you eat is when you should deploy your calories during the 36 hour fasting period. Personally I reserve almost all of them for a single meal that I eat at 6PM but you may want to mimic regular meals with three 200 calorie snacks or two small meals. To give you an idea of what 500 calories look like here are some examples:

6oz filet mignon (450 calories)

1 cup steamed broccoli (50 calories)

3 slices bacon (150 calories)

2 fried eggs (180 calories)

Small green salad with oil and vinegar - approx 2 cups (170 calories)

A Shake Shack single cheeseburger or Shack Burger without the sauce (470 calories)

A carrot (30 calories)

Breaking the Fast

In terms of breaking the fast I suppose a nutritionist would probably recommend a sensible meal of fruit and whole grains or some lean protein. I say go for whatever you fancy. The whole reason I fast is so that I can eat what I want. Not all the time, but enough that life is joyous. In fact the notion that something exquisite awaits me at the end of the fast keeps me going. That said, if you go completely off the rails on the five days of so-called unrestricted eating, jamming what you would have eaten in 7 days into only 5, you probably aren't going to lose weight. 5:2 isn't about strict calorie counting outside of the fasting period, but it presumes you will maintain a similar intake as you did before you adopted it. After adopting 5:2 and seeing the weight loss results I have become more mindful of how much I eat, if not necessarily what I eat. More significantly, not eating gave me a sense of empowerment and self control that I didn't anticipate.

Time Restricted Eating versus Intermittent Fasting

Similarly popular to 5:2, time restricted eating (TRE) is a daily fast that restricts consumption to a specific time window, for example eight hours, characterized as 16:8, or four hours know as 20:4 At its most extreme this might involve eating only a single meal in a day, known as One Meal A Day or OMAD. I have experimented with this form of fasting, and have used it as both a temporary replacement when traveling for work, and also in conjunction with 5:2. For example I never eat breakfast, although I do consume coffee in the mornings. But I do all of my early morning workouts in a fasting state. I find TRE effective on its own but personally I prefer 5:2 because it fits my work schedule better and also because I see other benefits such as a lower resting heart rate and better sleep. I recently started using a Whoop band to monitor my performance and it has shown significant benefits to fasting.

The Cost

Here's the thing about doing any type of fasting diet: it doesn't cost you anything but fat, hunger, and if you do it right a new wardrobe. There is no meal plan, no subscription service, no app, no foods you must consume, in fact quite the opposite. I am not going to say that it's easy, but it works if you can maintain the discipline. While I encourage regimentation at the beginning of your fasting journey, pick two days to fast and stick to them for at least three months, over time I found that I could vary the fasting day and even add an extra one or if need be skip a day and still maintain weight.

The Result

Using IF I went from 225lbs down to 180lbs in under a year, and maintained that weight comfortably since by employing 5:2 and TRE. While I am more mindful of how much and when I eat, and have drastically cut down on sugar and alcohol, I still consume more than enough foods to keep my life joy filled and my audience engaged. While I find low carb eating highly effective for losing weight, and especially during fasting because it is better at suppressing hunger, I find it aesthetically abhorrent and can never fully succumb to such tyranny. I am here for a good time, not a long time. But I also don't want that to be a shorter time than necessary.


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