Penn Jillette of Penn & Teller lost over 100 lbs on 1,000 calories a day

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You may know Penn Jillette as the talking member of the famous Penn & Teller magic team. (You may also know him as the creator of the excellent documentary Tim’s Vermeer. Seriously, rent and watch that film sometime.) He’s also been the larger member of the team, both in height and girth, up until now. Jillette lost over 100 pounds, nearly a pound a day, on a plant based diet. He also cut out added sugar, added salt and processed grains. As you can see from the “after” photo above and the “before” photo below, he looks like a completely different person.

Even master illusionist Penn Jillette couldn’t magically make his weight disappear – but he was able to drop from 330 to 225 lbs. by making a drastic change in his eating habits.

The 6’7” entertainer decided to get healthy after his high blood pressure landed him in the hospital.

“I was on six very powerful meds to bring the blood pressure down,” Jillette, 60, tells PEOPLE. “My doctor said I needed to get my weight down, and if I brought it down 30 or 40 lbs. it would be a little easier to control. And then he said something in passing that completely blew my mind – he said, ‘If you got down to 230, you probably wouldn’t need any of the meds.’ ”

The Wizard Wars judge decided to do just that, spending December through March on an “extreme low-calorie program” in which he consumed about 1,000 calories daily and was able to lose an average of 0.9 lbs. a day.

Since reaching his goal weight on his birthday, March 5, Jillette has stopped restricting the amounts he eats, and instead follows Dr. Fuhrman’s Nutritarian diet – this means he consumes no animal products, no processed grains, and no added sugar or salt.

“I eat unbelievable amounts of food but just very, very, very healthy food,” says the magician.

His typical daily diet consists of an “enormous salad” with vinegar as dressing for lunch (he doesn’t usually eat breakfast) and a dinner consisting of 3 lbs. of greens and three servings of black or brown rice with a vegetable stew, along with lots of fruits for dessert (his favorite is “an enormous amount of blueberries with plain cocoa powder”) and vegetables with vinegar or Tabasco sauce as a snack.

“I could probably have a steak or a doughnut every couple of weeks, but I just haven’t felt like it,” says Jillette. “When you’re feeling as bad as I felt, and you go to feeling as good as I feel, the temptation to go back to doing what you were doing when you felt bad is not very great.”

Although he wasn’t exercising during his extreme weight-loss phase, he now exercises every other day, doing the “scientific 7-minute workout” along with weight lifting, juggling and 10-mile tricycle rides.

“Now it’s really fun to exercise,” he says. “The only hard part of exercise is keeping it hard enough to be hard.”

Dropping the weight has come with many more pluses than dropping 10 pant sizes (from a 44 to a soon-to-be 34).

“I have so much energy and I feel so good,” says Jillette. “I’m just plain happier.”

[From People]

Eating a plant-based diet of just 1,000 calories is no small feat for Jillette, especially considering that he runs an atheist organization called The United Church of Bacon. (I’ve considered joining that.)

After Alanis Morissette lost a lot of weight and endorsed Dr. Fuhrman’s diet, I bought his book Eat to Live. As the article from People states, it recommends a nearly vegan, almost entirely plant-based diet if possible, to quickly and safely lose weight. Many people will say that 1,000 calories a day isn’t safe, but Fuhrman makes the argument that being overweight isn’t healthy, and that it’s safe to lose weight so quickly. He claims that many formerly overweight people with diabetes can go off their medication in weeks after they go on his diet. I tried it and it wasn’t sustainable for me. I do better with counting calories and having treats, but reading the book did give me the information which led me to significantly cut back my meat consumption, (which is also better for the environment) and to eat more vegetables overall. If you’d like to learn more about Dr. Fuhrman, this trailer for a PBS special he did is a good start.

Below is a recent video of Jillette arguing against the asinine “religious freedom” laws in Arkansas and Indiana that allow business owners to discriminate. (I’m including this because I like what he says and because I couldn’t find photos of him looking thinner than this. People has a photo though.) He makes the very cogent argument that no one is being asked to endorse gay sex, they’re “being asked to sell flowers and cake to people.” A woman with helmet hair and budget highlights tries to make the argument that journalists don’t have to write articles they don’t agree with, and he quickly shuts that down. The lady from the ACLU can’t get a word in edgewise. Then the CNN journalist, Don Lemon, (can you believe he is 49?!) says that as a person of color and a gay man he has seen the same bible verses historically used against black people and interracial marriage. Every one agrees with him except for helmet hair.

Sidenote: Jillette’s 9 year-old daughter is named Moxie Crimefighter and his 8 year-old son is called Zolten. Those are their actual names.

Here is another photo of Jillette before:

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58 Responses to “Penn Jillette of Penn & Teller lost over 100 lbs on 1,000 calories a day”

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  1. Boston Green Eyes says:

    Fun fact: Penn’s childhood home (he still owns it) abuts my sister’s home/property!

    • Sea Dragon says:

      Omgosh! You and your sis/family are so lucky!!

      • Boston Green Eyes says:

        Alas, I am not a big fan of his. I know a lot of people love him (including a close friend of mine), but to me, he comes across as a DB.

  2. Christo says:

    Wow, that is not many calories—especially for a man of his size. I suppose I could see that one would be using up part of their fat reserve to offset the missed calories one isn’t getting with the meager, daily 1000 calories. That being said, it would seem that his caloric intake would have to increase by the time he hit his goal weight because the average human body will burn 2000-2800 calories a day just to function in a sedentary position.

    That much fiber and greens, however, could prove to be counterproductive long-term. It is great to get him where he needs to be I suppose, but too much fiber can actually impede the body’s ability to absorb nutrients, including the ever-important calcium.

  3. taterho says:

    Cutting down on our meat intake wasn’t as hard for Mr. Tater (Or maybe it’s Mr. Ho) as we thought it would be. I was actually surprised at how quickly I noticed a difference in how I felt. I didn’t have that constant “blah” feeling. As for an entirely plant based diet, I couldn’t. I don’t have enough willpower.

    Love Penn and Teller BTW. Wasn’t Zolten the name of the fortune telling machine in “Big”?

    • Shambles says:

      I vote for Mr. Ho.

      I’ve stopped eating anything but chicken and fish, except on very rare occasions, and the blah feeling has stayed far away. You never realize how bad you feel until you start feeling awesome. Good for you and Mr. Ho.

      Side note: the fortune teller was Zoltar 😜

    • Wren says:

      Interesting. Without red meat me and Mr. Wren feel “blah”. We don’t have it every day, just once or twice a week, but we notice the difference if we don’t have it. I buy grassfed meat, local if I can, so there’s that.

      I could never do plant-based, I love dairy waaaaay too much and eggs are the best. But eating more veggies is never a bad thing, so I can totally get behind that.

      • Blackcat says:

        I am the same way with red meat. I rarely eat it, but when I do I feel so much better energy wise.

  4. AuroraO says:

    I lost 40 lbs by eating under 1000 calories a day for about 8 months and then when I started eating normally again I gained It all back. I wouldn’t recommend this kind of diet for something long term.

    • mytbean says:

      I think it also depends on what someone considers “normal” eating and what the body is doing with those calories. If you weigh a certain amount while eating X amount of calories then that’s how many calories it takes for you to weigh that much. Weight doesn’t change without permanent dietary and/or activity change. For some people it only takes a half hour walk around the block once a day to make a huge difference. For others it takes a mile plus a big calorie reduction. But again – Permanently. Going back to old ways will always result in regaining the weight and having the same body that was there before.

    • AcidRock says:

      Exactly what I was thinking. The issue isn’t so much difficulty in losing weight, but in keeping it off once the high level of restrictiveness in what can be eaten is lifted or even relaxed a little. And so many tend to not only gain back what they lost, but then some. The statistics on those who lose a great amount of weight and actually keep it off for a substantial amount of time are not very good; it’s a lifelong battle, and that simply cannot be sustained on 1,000 calories per day for the rest of one’s life.

  5. Jenns says:

    I’m sure I’m in the minority, but I think Moxie Crimefighter is a bada** name.

  6. Triple Cardinal says:

    The challenge will be to see if he can keep the weight off. He may be flying on endorphins right now due to such a large weight loss accomplished so quickly. But at some time, cravings may come back. He may tangle with a lack of energy and stamina. Or the tedium of such a restrictive diet.

    The body has very efficient ways of sabotaging itself.

    • RJ says:

      ITA-I lost over 100 pounds 4 years ago on 800-1,000 cals/day (I’ve always yo-yo’d and have always been on some sort of a “diet” since I was 10 yrs old) . The weight flew off and I maintained it for almost a year. Despite being careful with both diet and exercise, I eventually gained it all back and then some. Now, I’m slowly losing the weight again on a much more sensible 2,000 calorie/day plan of healthy carbs, fats, and lean proteins. I’d like to think I’m older and wiser, but the lifelong battle is exhausting.

    • moomoo says:

      I’ve eaten a plant-based diet for 18 years and for me it has been a wonderful long-term solution for weight control. I gained 15 lbs in 2 months during my freshman year of college — a lot of weight for my small frame. I tried to lose weight with diets but felt deprived and gained more weight. The weight finally came off when I went vegan for other reasons. I think it helped that I didn’t see it as a “diet.”

      After I improved my diet to a healthier whole food plant-based diet like the one Dr. Fuhrman recommends, my weight further declined. I eat as much healthy (and to me, it tastes delicious) food as I want and I don’t gain weight. I maintain great muscle mass similar to my teenage years. But when I choose to eat a bunch of brownies and processed foods for more than a week or so, I fairly quickly gain 1-2 lbs. The weight then effortlessly comes off when I go back to my normal whole foods plant-based diet.

      I hated being heavy and I feel that life has enough challenges without having to worry about my how my body looks or feels. Weight is not my primary reason for eating plant-based, but it sure is a nice bonus. For those who say they don’t have the willpower, maybe yummier recipes would help — lots of great web sites out there like Dr. Fuhrman’s site, fatfreevegan.com, Olives for Dinner, Vegan Richa, Post-Punk Kitchen, and Happy Healthy Librarian’s Facebook page. I don’t crave meat or dairy one bit.

  7. AK says:

    Tricycle rides?

  8. Francesca says:

    He is going to have problems keeping it off. Sounds like he is still over eating, just being able to keep to low calorie foods. “Enormous” servings and 3 lbs of food at a time is not the way a moderate eater eats.

    • Gen says:

      ^this is what I was thinking!

    • original kay says:

      That’s… just it. It’s not only what we eat, I think, but the portions we need to see on our plates. It’s still an emotional eating habit- the need to see big portions to feel satisfied, mentally.
      For a lot of us, eating is more mental than anything.

      I hope he finds a combination that works for him, long term. Getting the initial weight off is such a relief, that the rest is easier to handle I think (the mental part).

    • Wren says:

      He’s a huge dude, though. He needs more food than most people so I’m sure whatever is a serving to him is way too much food for almost everyone else. Huge portions of veggies is NOT a bad thing, and it really is nearly impossible to overeat on high fiber foods. As long as he’s eating a wide variety of vegetables and getting high quality protein from somewhere (not enough details here to judge), I hardly think it’s time to be worried about his health.

  9. Kara says:

    ugh Penn Jilette.

    just google “penn jillette feminism”

  10. shannon says:

    Dr. Fuhrman’s books are excellent, and he makes a really good point about the extreme low-cal, plant-based diets being best in order to drop significant amounts of weight. I would recommend the book “Fasting and Eating for Health.” I know fasting is considered dangerous and unhealthy, but I’d challenge everyone to read the science behind it and form their own opinion. In early 2012 I weighed 205 pounds and had horrible foot and knee problems. Working out was SO difficult. That spring I did a 10 day fast according to Dr. Fuhrman’s book, distilled water only for 10 straight days. I dropped to 172 lbs during those 10 days and LITERALLY overnight my nagging injury problems were gone. Exactly 3 years later, I run, bike, or do yoga every day and have been maintaining my 125 lb weight. People look at me in horror when I tell them I dropped 32 pounds during a 10 day fast…but I’m healthier now than I’ve ever been in my life.

    • frisbeejada says:

      I lost 50lb partially fasting on 500 calories for two days a week and that’s been tough enough. That was prompted by Achilles tendonitis in both ankles, now relieved by not carrying the equivalent of 100 bags of sugar. I am in awe of anyone who can go for 10 days on nothing but distilled water.

      • Boston Green Eyes says:

        I do the 5:2 diet, as well. I really like it. The first couple of times are difficult, but after that, it’s a breeze. I don’t weigh myself very often but I’ve probably lost about 15-20 lbs. since February.

      • frisbeejada says:

        I always have tons of energy on a fast day too, you think the opposite would be the case..

    • Francesca says:

      I love fasting. I never feel better than when on a fast. My fav is intermittent fasting. Eating during a five hour window. I am breastfeeding so not able to do it now, but I cant wait to get back to it.

  11. frisbeejada says:

    Wonder if he realises ‘Moxie’ is 18th century English slang for prostitute? Probably not.

    • sodizzy says:

      I think you are thinking of doxie. Moxie, I believe, has always been used in correlation to spunk or gumption. Edited because I’m a dumbass. That’s all I’ve got.

  12. LAK says:

    He really looks different.

    It’s amazing what motivation will do.

  13. Lisa says:

    Well, that’s going to suck long-term.

  14. Sabrine says:

    I have one day a week where I more or less eat what I want. It gives me something to look forward to and the knowledge that I won’t be permanently deprived of treats. Otherwise, it would be too restrictive.

  15. mytbean says:

    Good for Penn! I hope he keeps it off and that he feels great doing it! I think a restricted calorie diet is fine if it’s monitored by a physician and if the person on it is planning for a long-term future of healthy options and variety.

    I have such mixed thoughts on this stupid Arkansas issue. While I personally can’t fathom getting my panties in such a wad over any person or act that is deemed gay, straight or some shade in between, I come from a big city and have traveled a lot, and I can understand that there are people out there with such limited exposure to the rest of the world that they are put off by anything different than what’s accepted in their tiny environment.

    Admittedly, I haven’t kept up with the headlines because they seem as though they’d be really predictable so if my assumptions are leading me down ignorance lane, forgive and correct me.

    That being said, I can’t blame them for their socially conditioned ignorance and probably fear.

    I have to say that I understand but disagree with Penn’s argument that selling flowers/cake is not supporting the gay lifestyle when the baker/florist understands that these items are being used directly in ceremony for celebrating a lifestyle that will include gay sex.

    My thought on it is let businesses like this be the way they are and they will eventually wither out of existence because people won’t want their services. We can’t beat them over the head with this and expect them to willingly accept it and it’s their business to run as they see fit. So, if they want to slice and dice their client base until it’s all straight people of one religious ideal then so be it. They’re the one’s losing business by being idiots.

    • garciathes says:

      Notwithstanding the fact that I don’t trust the market to self-regulate, in issues of social justice included, the IN and AR bills make room for discrimination and are unconstitutional. Their proponents know this, and I suspect they know they’re not going to achieve anything, but they still cynically use the issue as a big slab of red meat to throw to the base.

    • Christo says:

      I can appreciate your reasoning, but I respectfully disagree. Essentially, you are indicating that the market corrects itself, and the market will take out these businesses that cite religious principles for not serving people. That isn’t true, however, in most cases. It took over 100 years for Brown v. Education and other civil rights cases to aid in helping resolve issues that the free market in NO WAY corrected since the Civil War and many would argue exist even today.

      Would you be ok with a Christian bakery not providing food for a Jewish or Muslim wedding? Afterall, both religions differ from Christianity and could, therefore, be “against” the religious beliefs of a Christian baker, who worships a different savior and book. Would you also be ok with the baker refusing service to a divorcee or someone who is rumored to have committed adultry or cheating? After all, using your logic, you are suggesting that any piece of cake or cookie put forth is tacit support of that individual. Should a baker also refuse to cater a Mormon wedding because they know that the religion is centered around the Book of Mormon, which many Christians do not recognize?

      You see where I am going here? There are limitless permutations of any number of scenarios—-all of which would have a basis in the universe that you are entertaining.

      While I would like to think that many of these business would lose customers in the long-run, ignorance has quite an activist, support structure that has maintained itself quite well throughout history. The nearly $1 million in funds that were raised for that lone pizza shop over the past week clearly demonstrates as much.

      • Sam says:

        Here’s my take on it:

        If I know that a business has a personal distaste for me, I don’t want them providing me a service. Okay, I’m a Christian Scientist. If I went to a baker and asked them to make my cake and then indicated that it was being made for a CS wedding and they expressed that they thought CS was immoral or wrong or bad and that they would no longer provide the service, what would I want?

        I would not want them to be compelled to make the cake for me, for two reasons: 1.) I wouldn’t trust them to not spit in it or otherwise “screw” with it in the first place just to spite me and 2.) I would not want to give MY green money to any people who hold such contempt for my religion. That’s pretty easy. I’d probably want to make a public airing of what happened because, mostly, I’d want other CS members to know that they shouldn’t patronize a business that holds such contempt for us and that other people who don’t like discrimination shouldn’t go either.

        I do feel like a great many reactions to this law are based in emotion and not based in actual law or economics. Frankly, I support anything that allows bigotry to be dragged to the front and exposed. In some way, I like that this law seems to be encouraging that. So while I dislike the law in principle, I also can appreciate it’s, uh, unintended side effects.

        And to answer your question – yes, I would be okay with a Christian bakery refusing to cater a Jewish event. At least in that case, the anti-Jewish bias has been laid bare and now the community knows how the bakery owners think. Sunlight is the best disinfectant, they say.

  16. Nikki L. says:

    No one is mentioning how awful this diet is for the human body long-term. It has little fat and almost no protein. Even vegans eat nuts and other sources of healthy fats and proteins. Losing 9/10ths of a pound a day is terrible for your body and your metabolism.

    Don’t follow this diet, it’s stupid.

    • GiGi says:

      I don’t know the details of this diet, but I have a friend who calls herself a “Low -Fat High-Carb Vegan” and I am actually worried for her health, because these people get so restrictive with their fats & that can be incredibly dangerous!

    • jwoolman says:

      If Penn followed Fuhrman’s plan, it included plenty of protein from large amounts of veg, mushrooms, nuts, seeds, beans, and a little grain. A good site to look at if you have doubts about vegan diets is jacknorrisrd.com – one of the detailed articles there on meeting protein requirements has a nice calculator for minimum protein needs based on ideal (not current) body weight. For instance, 110 pounders need 40 grams protein daily on the average. The body breaks down all protein into amino acids before building our species-specific proteins, and can get all the essential amino acids for humans from plant sources. We don’t need the amino acids in precise proportions from each meal, just over the course of a few days. So it’s a myth that we need “complete protein” foods like eggs or muscle meat, close to the human amino acid profile in proportions. Unless your idea of a vegan diet is eating nothing but grass, a normal variety of plant foods will also provide enough of our needed amino acids. The blend is just as complete, protein-wise.

      If you’re ever worried about getting enough protein or fat or fiber, just use one of the many free food trackers online or as phone apps. They’re aimed at people who want to lose weight but are useful for other purposes. I have flares in health conditions that make it hard to eat much sometimes, so I just track everything on my LoseIt phone app and can see if I’m meeting my protein/fiber goals on the fly and can decide what to eat next based on the running tallies. I also can see how my weekly averages are going and see a bar chart showing the calories from protein, fat, and carbohydrate for each day of a week. Very useful for me, since I can see if I make up shortfalls one day by eating more another day (which I usually do).

      • Nikki L. says:

        You’re right I’m sure, but as quoted in the article, what he’s eating isn’t enough for the human body.

  17. GiGi says:

    Well. I will say, from personal experience, that when I’m eating really clean, it can be hard to even get to 1000 calories, and I eat meat! For me, it’s not sustainable long term, because I end up feeling like, “How much kale can I stuff in my face to reach a normal calorie amount!?”

    I guess I admire his ability to stick with it & I’d imagine he *is* healthier now than before. But a bit of moderation is always good, right?

  18. Sam says:

    I doubt he’s going to be able to sustain this long-term. I’ve read Fuhrman’s stuff and even he makes it very clear that this is a short-term thing. You drop from a dangerous weight to a healthier one and then learn how to retool your habits .

    Penn did an interview with People where he stated that he landed in the hospital and was being given multiple medications, so it sounds like he was in a “lose weight fast” position – meaning the weight needed to come off relatively quick, so that’s what he did.

    And I’m unable to contain myself from noting the irony that Penn fell in with a person who advocates veganism, anti-obesity views and alternative medical practices after he railed against them on Bullshit several years ago. I’d genuinely be interested in knowing if any of his views from that show have changed over the years (I know he’s walked back his critiques of climate change and environmentalism, but that’s all I know about).

  19. lucy2 says:

    It’s great he dropped the weight, but for a guy his size, 1000 calories a day is way low. It’s essentially a crash diet, right? I have to think it would have been healthier long term to stick to a low but sufficient calorie intake and add exercise. Good luck to him though, hope he’s able to keep it off and keep feeling good!

  20. The Original G says:

    BTW, a huge part of the world’s population eats greens and rice everyday without issue and without the diseases of civilizations that are rampant in the USA.

    It’s time to question what has been regarded as “normal” eating.

  21. jwoolman says:

    Fuhrman’s book is well worth reading, you don’t have to go vegan to benefit. The Kindle version is only about $10. Plenty of references to the medical literature to back up what he says. There are hundreds of reviews on Amazon showing that people can use his ideas as the basis and adapt it to their own preferences and still get good results (the reviews are worth reading, too). Just seriously boosting up veg (especially greens), mushroom, and fruit intake can make quite a difference. I think he’s right that cravings for simple carbohydrates are related to unsatisfied need for vitamins and minerals best absorbed from veg and fruit. I think the body figures “need vitamins, need minerals, those come in carbohydrate packages- oh, there’s a bag of Oreos!”.

  22. jwoolman says:

    By the way, Fuhrman’s approach doesn’t count calories so 1000 calories per day was Penn’s choice. Pretty drastic for a guy his size (not drastic for a small sedentary woman), but he had a serious health issue to fix quickly and he was under medical supervision. Fuhrmann gives guidelines in term of maximum and minimum amounts of types of food for his six week plan for people with serious health issues requiring weight loss to resolve. For example, at least 1 pound of raw non-starchy veg, at least one pound of cooked (veg includes mushrooms). At least 4 servings of fruit. At least 1 cup of beans, at most 1 cup of starchy veg or grain. At most 1/4 cup (I think) of nuts/seeds, but have 1 tablespoon ground flaxseeds a day in addition. He recommends avoiding animal products and wheat/gluten for the initial phase but gives guidelines for introducing them if you prefer. He says to add more food within the guidelines as needed. So ordinarily a guy Penn’s size would be eating a lot more than 1000 calories even for weight loss. Fuhrman recommends generally limiting low nutrition foods to 10% of your total calories, I think.

    • Bridget says:

      That’s interesting, because the 1000 calories a day was definitely something that stood out to me. That’s a miniscule amount of calories – most women wouldn’t be able to sustain a diet like that and still menstruate (which is a big sign that you’re not consuming enough calories).

      But a plant based diet is both good for people amd the environment. Eat real food.

  23. Mary Jane says:

    I ne’er realised he’s 6’7″! I always just figured Gillette was shorter than average.

  24. Dotty says:

    Now he looks like Ice-T with wireframe glasses.

  25. CH2 says:

    It’s kind of funny how we have no concept of moderation in America… Either we’re consuming vast portions or whittling our caloric intake down to nothing. There’s no real middle ground here and that’s why we often see people who are REALLY fit and REALLY into their health and then people who are just completely out of shape and have stopped caring.

    It’s kind of like the political system, too. So binary and nothing in the middle…

    My husband and I always say “America is the land of extremes”

  26. Meg says:

    I thought if you cut your calories too much your body goes into starvation mode. How could he cut calories down to 1,000 and lose weight? Once he lost a lot he could gradually keeping cutting back but to go right to 1,000 per day?

    • jwoolman says:

      It generally takes many months to go into true starvation mode. Our bodies are built to withstand long periods of food shortages. He was probably pretty sedentary at least in the beginning because of his health issues. His body might be very efficient at converting fat to energy, that does vary. Or maybe he just counted wrong… 🙂

      It’s true that some people find weight loss stalls if they eat too little, particularly when they are very active. So if they eat more, weight loss revs up again. It’s always worth a try if you stall too long. But that stalling (the dreaded plateaus) might take quite a while to kick in and also simply doesn’t happen for everybody.

      The numbers for calories in vs calories out are all approximations anyway, so there is a lot of slop in the counting. Those numbers on packaged food can be off by 20% and still legal, and sometimes much bigger discrepancies are found. That might be a factor also.

      People preparing for things like lap band surgery report being instructed to go really low on calories for a while (maybe 500 calories sometimes?), but they seem to still lose weight. And of course people deliberately undergo full water-only fasts for long periods for health reasons. The body adjusts pretty quickly to that. So apparently we’re quite flexible. Medical supervision seems wise when possible, though. And Penn was obviously supervised. A big problem if eating too little is insufficient intake of micronutrients (vitamins and minerals), which are not always absorbed well enough from pills. The magic numbers of 1200 calories minimum for women and 1500 calories for men are guesses based on that, and really the true numbers vary considerably depending on individual size and absorption efficiency. Lack of protein could result in muscle loss eventually, depending on what you’re eating. But 1000 calories per day for a few months might not cause many problems even for someone Penn’s size when eating carefully, on his diet he was getting far more micronutrients than many Americans eating two or three times as much. He might even have had enough protein.