What It’s Like To Eat Space Soup For Five Days, Or An Honest ProLon Review

By Mary Kate Fotch | May 10, 2021

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Welcome back to another installment of the fad diet diaries, a series in which every six months or so someone casually emails me and is like, “hey do you feel like suffering for a week in the middle of a pandemic, where food and alcohol are pretty much your only reliable sources of joy?” and I say “Hey, yeah that sounds cool, ship me the box of space soup.” Last summer I spent three days consuming literally nothing but hardboiled eggs, overcooked steak and white wine, and then had to lie down for the next eight months and reflect on my choices. Today I am back stronger than ever, having made the wise decision to this time embark on a diet program that was designed by someone who at least appears to have been formally educated in the field of health, which is a vast improvement over the martini-soaked magazine editor who created the last abomination.

Last week I completed ProLon, which is a five day plant-based cleanse that’s meant to mimic fasting. Why? Because according to Dr. Valter Longo, Professor of Gerontology and Biological Sciences and Director of the Longevity Institute at the University of Southern California and (more notably) the engineer behind ProLon; fasting helps to promote cellular regeneration, which in turn reduces the risks of cardiovascular, neurodegenerative and autoimmune diseases as well as diabetes, cancer, and dementia. My ProLon box came with a free copy of Dr. Longo’s The Longevity Diet, which describes his research in detail as well as a lifelong routine to adopt after you finish the cleanse. I had every intention of reading the entire book until I realized how much sleep is required during this fast, and immediately opted to go to bed the second I finished work each day instead. But as far as I can tell, the lifelong diet he recommends is essentially just the Mediterranean Diet, which for all intents and purposes isn’t a bad habit to adopt at all.

If you’re anything like me, you may find the concept of a fasting-mimicking diet confusing, because the last time you checked fasting had some pretty hard and fast rules, the first of which being “no food” and the last of which also being “no food.” The first selling point of ProLon: you do, in fact, get to eat food. Is it food that you would typically eat? Not unless you spend a lot of time in space or a dystopian sci-fi movie, but it is still technically food. And the best part? It’s not food that you really have to cook. You may not think that’s something that I would consider a benefit, but I can assure you that by day three you hardly have the energy to rehydrate your soups and let them simmer for 15 minutes, let alone prepare an actual meal.

What ProLon provides in convenience, it depletes in joy. Sure, your pre-packaged food saves you time and energy, but you can’t use any of that extra time to drink coffee or alcohol, so what is the point? The website stresses that the ideal cleanse measures are no caffeine or alcohol, but if you must, you can have one 8 oz. cup of black coffee a day. Considering there are zero calories in black coffee, I didn’t really understand the rationale in limiting myself here, but nevertheless I sacrificed my thrice-daily milky coffee to the Fasting Gods in the name of scientific integrity.

In the name of mental integrity I cracked on day four and drank wine, something for which I will be making zero apologies.

The Cleanse

ProLon arrives in a very sleek looking white box that made me feel a little bit like an influencer, a brief moment of self-importance that quickly passed after I spent longer than I am comfortable admitting attempting to get a good unboxing shot. Let’s give the girls credit where credit is due.

The white box contains a large branded water bottle which I absolutely plan to take to workout classes once gyms open again to fuel my disproportionate sense of superiority, and five smaller white boxes labeled 1-5. Each of these tiny boxes contain your allotted food for the day, which can be eaten in any order you please, but cannot be traded to a different day. The contents of each minuscule box varies slightly by day, but essentially you’re getting the following: herbal tea and a nut bar for breakfast, a soup and vitamins for lunch, an afternoon snack of herbal tea and either kale crackers or green olives, a different soup for dinner, and on blessed days, a Choco Crisp bar for dessert. I adhered to the schedule ProLon laid out for me except for a few minor tweaks, because I knew any kind of divergence from their plan was a slippery slope to me eating my entire day’s worth of food before lunch and then lying in my bedroom in the dark for the rest of the afternoon.

The food, for the most part, was far better than I expected. That could have been the hunger talking, but to be entirely honest with you, I don’t think it was. With the exception of the cursed tomato soup (more on that later), nothing I ate during the cleanse was something that I wouldn’t at least technically enjoy in real life—I just would have liked double the serving size. But the secret ingredient that allows you to go about your day in a semi-functional matter is not the food at all, but the L-Drink.

It will shock very few people when I say that I did almost zero research before diving into ProLon, beyond a couple cursory reviews of their website which I would optimistically label cautiously vague. It isn’t that I didn’t care about what was about to happen to me, but more that I didn’t want to build up any kind of expectations at all—overestimations or not. All I needed to know was that I didn’t need to know anything beyond the contents of my daily box of food. It was almost comforting in a way, having all options or input removed. I literally just had to show up and participate.

However, all that went out the window two bites into my first soup—a creamy butternut squash that was just a tad too sweet for my taste—and I immediately took to Google to figure out whether any kind of seasoning was allowed—don’t worry, it is—a whopping one teaspoon a day. It was at this point that I stumbled upon a series of Goop articles about ProLon and recognized the kind of company I was in. This isn’t just a topic Goop covers—they are, in fact, an approved ProLon retailer, which immediately upped the stakes here. I’ve tried more than my fair share of fad diets, but taking part in a Gwyneth Paltrow-approved cleanse is a whole level of white woman that even I personally didn’t ever believe I’d aspire to.

It turns out Prolon is a staple at the Goop headquarters in Santa Monica, a place that I think I would fear and revere in equal measure. You can spot one of the cleanse’s many disciples from a mile away as they’re all carting around two key accessories: the gigantic clear water bottle filled with a hot pink beverage and an instantly recognizable, dead-behind-the-eyes expression which is pretty much your constant companion from days two through four. The pink beverage is our revered L-Drink, and it is the only reason I am able to sit here and tell you this tale without any major bouts of PTSD.

While ProLon’s site didn’t offer much detail in the ways of the L-Drink, I learned from one of my new contemporaries at Goop that it’s a glycerol, plant-based beverage that helps keeps you full in between your baby mouse-sized meals. Every day except for the first you’re given a small bottle of either lemon or orange flavored L-drink (I discerned zero difference between the two), which you’re meant to mix with 950ml of water in the branded ProLon water bottle. What makes this enjoyable, other than the fact that it’s the only thing standing between you and starvation, is that you’re given two bags of herbal hibiscus tea to steep into the mixture, the source of the vibrantly pink hue that I lived in fear of spilling on anything white I was wearing at any given moment in those four days.

The L-Drink was so effective that I contemplated tapping into my leftover reserves—because you only mix a certain amount into your water bottle based on your weight—for life post-ProLon when I just wanted to keep myself from snacking all day. This felt like a dangerous habit to adopt, hoarding hibiscus tea and half-used glycerol bottles all summer, but that doesn’t mean I’m not still researching ways to recreate it. Watch this space.

The Food

As for the rest of the contents of the daily diet boxes, I was pleasantly surprised. The morning nut bar is delicious, albeit incredibly oily. I like to think that’s because it’s actually just a bunch of ground-up nuts that have been mashed together in a bar shape, and not any other far less savory explanations. As someone who is very inconsistent in her breakfast routine on work days, it was nice to have something to look forward to. There was a steep learning curve on my part in learning how to savor the bar over the course of an hour rather than inhaling it in three bites, but that’s okay. Don’t be fooled by this glamorous lifestyle, I too am an incredibly flawed human constantly capable of growth.

Of the two snacks, I definitely prefer the cracker days to the olive days. Not because the crackers taste better than the olives, but because they are substantially more filling. The olives, to my surprise, were just a pack of standard green olives, kind of like the ones you can buy in the Trader Joe’s checkout line and then eat on the drive home as a pregame for the actual groceries you just bought. The only issue I had with them were that each packet contained about seven olives, which in my books is about half the amount of olives I would like to consume in a single serving.

I would describe the kale crackers as… hearty. In all fairness, if it was the same cracker with a slab of brie on it, I wouldn’t have thought about the contents of it at all. But because I was usually pairing it with, at the best of times, soup, and more often than not, air, I was incredibly focused on just how fibrous they were. This came in handy later when I illegally paired them with wine, but I’m assuming most participants wouldn’t have that experience.

The Choco Crisp Bar served two real purposes as far as I can tell: to trick yourself into thinking you were ending the night with a treat and to give your jaw such an extreme workout that you would be grateful to be consuming nothing but soup for five days. Real talk, if you have TMJ, you probably can’t do this diet. Sorry to disappoint, but I’m saving you the embarrassment of being rushed to the hospital and having to explain that your jaw is locked into place because of a Goop cleanse. You’ll thank me in the long run.

Was it sweet? No, which was kind of nice. The Choco Crisp Bar could best be described as a handful of slivered almonds and potentially a sprinkling of sawdust, glued together by a tar-like semisweet chocolate substance. That’s not to say I wasn’t ecstatic on the select days when I would open up my box in the morning and see it resting at the bottom like a rare gem. But don’t label something Choco Crisp when it is, in all honesty, neither of the above.

But let’s get down to what we all really care about here: the soups. I would be lying if I didn’t tell you that I view any kind of food you just add water to and heat with a dubious apprehension. Is the phrase “dubious apprehension” redundant? Yes. That’s how concerned I was about the soups.

As already mentioned, I learned halfway through my first soup that you are in fact allowed to add seasoning, which in my opinion was a total and complete game changer. I went so far as to find a website with suggested spices to add to each soup, just in case you’re the kind of person who doesn’t know how to add 1 teaspoon of any seasoning that you like to a bowl of soup. No judgment, we’ve all been there.

I thought about adhering to these “recipes” for all of 30 seconds before resorting to a mixture of my go-to seasoning for literally any and all meals: garlic powder, chili flakes, Trader Joe’s Vegan Chicken-less Seasoning Salt. This gave just about every soup I tried a vaguely ramen-esque flavor, something I’m sure Gwyneth would not be disgusted by at all.

ProLon has recently released a second variety of their diet plan with a new set of soup flavors, so I opted to test out this version under the assumption that they had to create a secondary set because the first was inedible. Not sure if that’s true, but would love to hear from someone who has tried both and lived to tell the tale.

My pro-tip for the soups, beyond seasoning them, is to actually cook them for the recommended time on the package. If that feels like an obvious recommendation for you, may I remind you that I had to Google which seasonings pair best with each soup, so we’re probably not starting from the same baseline here. Once I figured out that cooking times do, in fact, matter, my soups went from watery bowls of garlic salt liquid to something much more closely resembling actual food. Science is wild, right?

Without further ado, I am happy to present to you the definitive ranking of ProLon 2 soup flavors, from “I would eat this again” to “I would not feed this to my worst enemy except for that one—she knows who she is.”

Butternut Squash & Quinoa

No joke? This is delicious. The consistency was thicker than the rest of the soups—almost like a puree until I added some extra water—which gave the illusion of actually eating a normal sized serving. This soup + some warm crusty bread in the winter? I would be happy.


As someone who doesn’t really like actual Minestrone soup, I was shocked by how much I enjoyed this. This one felt the most like real food because it had small dehydrated vegetables floating in it. I recognize that doesn’t sound like the glowing recommendation that I think it is, but perspective is a crazy thing when you’re eating powdered soup for five days straight. Minestrone only made one appearance in the whole cleanse, but she was a stand out.

Black Bean

Even with my breakthrough around cooking times, I could still never get the black bean soup to the consistency that I would have preferred. This could be due in part to the fact that I was standing on my couch screaming to “The Way I Loved You (Taylor’s Version)” while I was meant to be watching it cook, which led to half of my dinner boiling over onto the countertop, but I guess we’ll never know for sure. Even with the undesirable consistency, it still tasted good. Like if you were to make chili from scratch, but you’re remembering the recipe after it was screamed to you through a bathroom door at a loud bar.

Butternut Squash

I don’t know why the Butternut Squash soup is so vastly inferior to the Butternut Squash & Quinoa soup, but it must make family gatherings really uncomfortable. These two are the only acceptable use of the “I ain’t ever seen two pretty best friends” meme. Butternut Squash was just a bit too sweet, even with the addition of my now-infamous spice trio, but it had one of the best consistencies of all the soups so we’re going to let it slide.

White Bean & Spinach

Listen, I wanted to like this one so bad. I love a white bean just about anything. I love a spinach just about anything. This had all the makings of a hall of famer, and it just never delivered. I don’t know if it was my subpar cooking skills or the actual soup itself, but the mixture never fully dissolved either time I had the White Bean & Spinach soup, leaving this sad grainy mixtures for the last half of my meal. Flavor wise it wasn’t terrible, but even good-tasting sand is still sand. Sorry babes.


I have never known such personal insult as the ProLon Tomato Soup, which has the gall to not only show up in both flavor packs, but also the audacity to pretend it isn’t dehydrated ketchup in a bag. When heated, it becomes this gummy, gelatinous mess that would only be tolerable if I was dipping french fries onto it, and even then it would be touch-and-go. To add insult to injury, you’re not even allotted any crackers on tomato soup day, which means you just have go in raw dog with a spoon and hope for the best. In this case, “the best” means the soup is so hot that it incinerates your taste buds and then you’re only left to struggle through the godforsaken texture. At least they have the decency to give it to you on Day Four when your stomach has shrunk enough to point where you aren’t upset about tossing half of it out and chugging some extra L-Drink instead. May you never darken my doorstep again, you sad excuse for one half of the greatest culinary combination known to man—Tomato Soup & Grilled Cheese.

The Results

What I’m about to tell you pains me for a more than a couple reasons, the first of which being that this entire series was established to dismantle the hype around fad dieting and the second being that I never thought I would be someone who endorsed a $250 cleanse. Perhaps it’s hindsight speaking here, looking back through rose-tinted glasses at what was objectively five very difficult days of my life and painting them as something else entirely but… I may be a ProLon convert.

Did I lose weight? Yes. Is that why I’m supporting this cleanse? No. Losing weight is inevitable when you’re maxing out at 800 calories a day, tops. At that level I could have been eating nothing but ice cream for a week and still lost weight. I know because I’ve done it, and let me tell you—how I felt after five days of ProLon is lightyears different.

As is the case with any diet, on Day One I was too wrapped up in my new routine to really feeling anything. Sure, I was hungry from time to time, but that was overshadowed by all the rituals and processes that I was adapting to. By the end of the day, the lack of calories had taken a toll and I went to bed at 9pm.

Day Two was spent in a total haze. I felt like a valium-soaked housewife and couldn’t muster up the energy to care about a single thing. My biggest concern of the day was the fact that yoga studios were still closed, because I would have given just about anything to go to a Yin class and lie on the floor in a dark room for an uninterrupted 50 minutes. At one point there was a tightness in my chest that I would usually associate with severe anxiety, except upon further inspection there was no anxiety to be felt anywhere within the vicinity of my body. I couldn’t have produced a sense of urgency were my apartment to have gone up in flames around me. Was this transcendence? I’m not sure, but if I could re-create the sensation once a week I would probably be a better person.

However, the pendulum swung in the opposite direction on Day Three, where I was not only the opposite of carefree, but also hyper-aware of everything around me. It was like being on Adderall except without any of the fun parts. Day Three is meant to be the hardest because it’s the day with the least amount of food, and I spent every second of it being intensely aware of that fact. I got out for a walk after work but was nearly brought to my knees by the smells wafting out of the Thai restaurant across the street, which was quickly followed by another 9pm bedtime.

Day Four was the first morning I woke up truly hungry, but that particular issue was quickly overshadowed by a hectic work day, which, combined with the L-Drink, had me arriving at mid-afternoon before I even thought about lunch. I didn’t close my laptop until 8pm, at which point there was one thing on my mind and one thing only: wine. I waffled back and forth on this for far less time that I probably should have, before ultimately deciding that Taylor Swift releasing Fearless (Taylor’s Version) was a sign from above for me to abandon some of the stricter points of my cleanse. The pinnacle of self-control, I traded out my Choco Crisp Bar for one (1) glass of red wine, turned the speaker up as loud as it would go, stood at my window overlooking the sunset and thought that this was probably as close as I’d ever get to being one of the moms on Big Little Lies.

Me pouring “one (1) glass”: 

Then before I knew it, Day Five dawned, and there’s no other way to say it: I felt fantastic. I wasn’t hungry. Wasn’t tired. It was a Saturday morning and I opened my eyes at 7:30am, unbothered by trivial human needs such as breakfast. I went about my day, running errands, tidying the house, and preparing for an entirely un-Prolon sanctioned wine tour that night, which I had decided I had earned the right to attend. I went from house to house, sampling wines with my kale crackers in tow—tiny stale companions that kept me from diving face first into plate after plate of hors d’oeuvres. I thought about feeling guilty for breaking the rules for approximately 30 seconds before I remembered that I have spent the last four months trapped inside, the last three months in the throes of a Dutch winter, the last five days eating powdered soup, and sometimes you just need to let yourself live a little.

I woke up on Day Six hangover-free, five pounds lighter than I was at the beginning of the week, and with zero desire to eat something greasy or carb-filled, at which point I was ready to call up Goop and demand a job application. More than any of that, I just felt good. Physically, emotionally, mentally just lighter than I had felt in some time. I don’t think it’s something I would have noticed if that last year hadn’t been what it was, but I was overcome by a sense of peace that I hadn’t realized I had been missing for quite so long. It briefly occurred to me that I could have been mistaking lightheaded for lighthearted, but the feeling lasted even after I ate something that didn’t come in a shiny white ProLon package.

I turned on my favorite podcast, took a walk to my favorite coffee shop, grabbed a full dairy latte, and took my time meandering through the still streets of early morning Amsterdam. I sat on a bench and watched a few boats go by, wondering if this brief moment of absolute serenity is how Gwyneth Paltrow feels every single day of her life. And then I remembered that money, and the experiences that it affords you, is a hell of a thing.

I am not saying ProLon is magic. I’m not saying that fasting is for everyone. I’m definitely not saying you need to spend $250 to feel good about yourself. But what I am saying is that after months of inactivity spent in lockdown, lacking the motivation to take care of myself to the level my pre-pandemic standards dictated—standards that I did not realize I had been entirely taking for granted—ProLon served as a turning point. It’s been one week and I have by no means adhered to the letter of the law for Dr. Longo’s Longevity diet. But I have been more mindful and active than I can remember being in months. And that, to me, is worth all the rest of it. Just make sure you listen to your body and let yourself have the damn wine if you need it.

Images:  Mental Art + Design / Stocksy; Mary Kate Fotch (2); Giphy (2)

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