The Guy Who Stopped Eating Food (A Testimony)

Rob Rhinehart: Food is the fossil fuel of human energy. It is an enormous market full of waste, regulation, and biased allocation with serious geo-political implications. And we’re deeply dependent on it. In some countries people are dying of obesity, others starvation.

In my own life I resented the time, money, and effort the purchase, preparation, consumption, and clean-up of food was consuming. I am pretty young, generally in good health, and remain physically and mentally active. I don’t want to lose weight. I want to maintain it and spend less energy getting energy.

I hypothesized that the body doesn’t need food itself, merely the chemicals and elements it contains. So, I resolved to embark on an experiment. What if I consumed only the raw ingredients the body uses for energy? 

Would I be healthier or do we need all the other stuff that’s in traditional food? If it does work, what would it feel like to have a perfectly balanced diet? I just want to be in good health and spend as little time and money on food as possible.

Image Credit: Ray Laskowitz

I haven’t eaten a bite of food in 30 days, and it’s changed my life.


There are no meats, fruits, vegetables, or breads here. Besides olive oil for fatty acids and table salt for sodium and chloride nothing is recognizable as food.

I researched every substance the body needs to survive, plus a few extras shown to be beneficial, and purchased all of them in nearly raw chemical form from a variety of sources. 

The section on the ingredients ended up being quite long so I’ll save that for a future post. The first morning my kitchen looked more like a chemistry lab than a cookery, but I eventually ended up with an thick, odorless, beige liquid.

I call it ‘Soylent‘. At the time I didn’t know if it was going to kill me or give me superpowers. I held my nose and tepidly lifted it to my mouth, expecting an awful taste.

It was delicious! I felt like I’d just had the best breakfast of my life. It tasted like a sweet, succulent, hearty meal in a glass, which is what it is, I suppose. 

I immediately felt full, yet energized, and started my day. Several hours later I got hungry again. I quickly downed another glass and immediately felt relief.

The next day I made another batch and felt even better. My energy level had skyrocketed at this point, I felt like a kid again. 

But on day 3 I noticed my heart was racing and my energy level was suddenly dropping. Hemoglobin! I think, my heart is having trouble getting enough oxygen to all my organs. 

I check my formula and realize iron is completely absent. I quickly purchase an iron supplement and add it to the mixture the next day. I have to be more careful not to leave anything out.

On day 4 I noticed how much healthier my skin was. It’s long been dry and rough, with splotches and red bumps but now it’s soft, smooth and clear. 

Before I rarely had enough energy to go to the gym, but this day I had plenty so I decided to put the diet to the test. I’d been running off and on for several months, never able to do more than a mile straight, but this day I ran 3.14 miles non-stop. This is an irrational improvement.

My cravings and tastes closely matched with my needs. One day I accidentally put in a tablespoon of salt, rather than a teaspoon. I immediately noticed the mixture tasted unpleasantly salty. When I was deficient of iron I felt a strong craving for red meat. As I started running longer distances I craved more carbohydrates. After a week advertisements for fast food looked repulsive. All I crave is Soylent.

Week 2 was rough since I started experimenting with the proportions, trying to find the optimum amount of everything. When I was off I paid for it dearly, but I soon found just the right mixture.

The rest of the month went smoothly. It quickly became part of my routine and I didn’t have to think or worry about it. I was fully expecting to crave traditional food, but I don’t as long as I’ve had my Soylent. Hunger comes from two chemicals triggered by a lack of nutrients, ghrelin and leptin, as well as mechano-sensors in the stomach. 

If there’s something in your stomach and all your nutritional needs are met you won’t feel hungry. I feel full after drinking a single glass of Soylent and while the smell of Mexican food from the street used to drive me crazy, now I am unaffected. It’s like finding a new partner you really care about. When all your needs are met, you don’t have a desire to stray.

RESULTS — Quantitative

I had my blood tested in two ways: complete blood count and chemical panel, and got a lipid panel near the end. This shows stuff like red/white blood cell counts, Na, K, P proportions, and more. The internist had to bill it as “testing for blood-borne diseases”. 

She said a lot of providers do not support preventative care, which I thought was strange. I also monitored my heart rate, and bought a glucose meter to track my blood sugar (I’m not diabetic). I am 6’3″ so my BMI was on the upper end of normal at the start. Remember I am not trying to lose weight here.

I wasn’t able to get a lipid test until week 3 but my triglycerides and cholesterol are certainly low now. I have a family history of heart disease, but my risk is now well below average.

I also got my genome sequenced. Genetically, my body’s response to exercise should be typical, along with my response to diet, though on average I should have a slightly higher BMI, consistent with my status before the experiment. My LDL cholesterol is subject to be slightly higher than average, while my HDL levels typical. 

Though this is only one case, it should be representative of most people since my diet and exercise genetics are typical. Some people can eat all they want and never gain weight, others can’t shed pounds no matter how hard they try. The trick is in the genome, though both extremes are uncommon. 23andme is awesome!


I feel like the six million dollar man. My physique has noticeably improved, my skin is clearer, my teeth whiter, my hair thicker and my dandruff gone. My resting heart rate is lower, I haven’t felt the least bit sickly, rare for me this time of year. I’ve had a common skin condition called Keratosis Pilaris since birth. That was gone by day 9. 

I used to run less than a mile at the gym, now I can run 7. I have more energy than I know what to do with. On day 4 I caught myself balancing on the curb and jumping on and off the sidewalk when crossing the street like I used to do when I was a kid. People gave me strange looks but I just smiled back. Even my scars look better.

My mental performance is also higher. My inbox and to-do list quickly emptied. I ‘get’ new concepts in my reading faster than before and can read my textbooks twice as long without mental fatigue. I read a book on Number Theory in one sitting, a Differential Geometry book in a weekend, filling up a notebook in the process. 

Mathematical notation that used to look obtuse is now beautiful. My working memory is noticeably better. I can grasp larger software projects and longer and more complex scientific papers more effectively.

My awareness is higher. I find music more enjoyable. I notice beauty and art around me that I never did before. The people around me seem sluggish. There are fewer ‘ums’ and pauses in my spoken sentences. My reflexes are improved. 

I walk faster, feel lighter on my feet, spend less time analyzing and performing basic tasks and rely on my phone less for navigation. I sleep better, wake up more refreshed and alert and never feel drowsy during the day. I still drink coffee occasionally, but I no longer need it, which is nice.


I used to spend about 2 hours per day on food. Typically I would cook eggs for breakfast, eat out for lunch, and cook a quesadilla, pasta, or a burger for dinner. For every meal at home I would then have to clean and dry the dishes. This does not include trips to the grocery store. 

Now I spend about 5 minutes in the evening preparing for the next day, and every meal takes a few seconds. I love order of magnitude improvements, and I certainly don’t miss doing dishes. In fact I could get rid of the kitchen entirely, no fridge sucking down power, no constant cleaning or worrying about pests, and more living space. I just need a water source.


Monthly I was spending about $220 on groceries, and another $250 eating out for lunch and the occasional dinner. The average american spends $604/month on food, about half of which is groceries.1,2 As a percentage of income this is actually the lowest of any nation. Kenyans for example spend 45% of their income on food.3 

I used to dream of one day being able to afford shopping at Whole Foods, but now it’s irrelevant to me. Consuming only Soylent costs me exactly $154.82/month another order of magnitude improvement, and would be cheaper if I didn’t need the energy for running every day. At scale the cost would be even lower.

The Quantified Diet

It’s wonderful to have full visibility and control over what’s going in to my body. Besides making food allergies irrelevant, it’s trivial to increase or reduce consumption of a particular substance by a precise amount. 

I am hopeful diabetics could use this to control their blood sugar. I was able to control mine to within about 5mg/dL by varying carbohydrates and fiber. Starting a more intense workout routine? Increase protein and carbohydrates 20%. Want to lose some weight? Reduce fat consumption by 30% (don’t eliminate it entirely!). 

Blood work shows potassium deficiency? Increase it by the precise amount required. In fact, unless you work on a banana plantation you’re probably not getting the recommended amount of potassium (3500mg is 9 bananas), and never have. Ever wonder what it would feel like if you did?

Social Implications

As any Instagram user knows, food is a big part of life. Food can be art, comfort, science, celebration, romance, or a reason to meet with friends. Most of the time it’s just a hassle, though. Americans only eat out for 12% of meals. 

I think it would be nice to have a default, healthy no hassle meal. Similar to drinking water most of the time, but wine or beer when you’re socializing. If you saved money on food at home you would have the freedom to go out more often.

I for one would not miss the stereotype of the housewife in the kitchen. Providing diverse, palatable, and nutritious meals for an entire family every day must be exhausting. What if taking a night off didn’t mean unhealthy pizza or expensive take out? 

How wasteful society has been with its women! The endless hours spent cooking and cleaning in the kitchen could be replaced with socializing, study, or creative endeavors. And why beg children to eat vegetables? Soylent has every vitamin and mineral the body needs, and it’s delicious.

To me diet always seemed to be a trade-off. Time, money, health: pick two. You certainly have the capability to be healthy, but it will cost you. What about the single mom, the poor student, struggling entrepreneur or artist, the unemployed, or the elderly? These people desperately need energy, and its harder for them to be healthy than anyone else. 
Living on fast food and ramen is cheap and convenient, but unhealthy. Shopping at places like Whole Foods costs a fortune to many people and cooking healthy recipes takes practice and time. Cooking should be a hobby, like hunting. People used to hunt for survival, now they just do it for fun.

Global Implications

With Soylent you can be in peak mental and physical condition for less than $2/day. Soylent does not spoil for months, does not require refrigeration, is easy to transport, cheap and environmentally friendly to produce, contains no pesticides, hormones, or preservatives, is trivial to prepare, without even requiring a heat source (though you do need clean water), does no harm to animals, and drastically lowers sanitation requirements. 

I almost forgot to mention, when everything going in to your body is diffused in to the bloodstream, you don’t poop. I only have to remove a few grams of fiber from my system per week. I also noticed I was generating far less trash than before. The vast majority of personal refuse is food-related. Why else would the trash can always be in the kitchen?


This is one case and it’s only been a month, so it’s early, but I’m certainly not stopping now. Also, every body is different and there may be long term effects so more data is necessary. 

However, I am consuming no toxins or carcinogens and I get all the nutrition and energy I need with about 1/3 the calories the average American consumes so I hope in the long term my longevity will be improved (caloric restriction has been shown to reverse the effects of aging in rodents)4,5 while lowering my risk of cancer and disease. 

If you would like to try this experiment as well please contact me so we can pool our results. It’s fine to have a normal meal too, nutritional fundamentalists really irk me. The point is freedom, you don’t have to. 

I started consuming Soylent exclusively just to test the effects. I see nothing wrong with eating traditional food as well, I just don’t have much of a desire to. The only thing I missed was eating with friends. Now that 30 days are up I’m going to start doing that again. I only drink socially, and now I only eat socially.

I notice only now how much of this city is devoted to the stuff. Wherever you are I challenge you to find a search term for google maps that returns more results than “food”. Travelling back home to the American south I am still shocked to see how prevalent obesity is. 

How many people still spend their lives just surviving, living to eat, and it’s killing them? The food is eating us. I don’t know how to change peoples’ behavior, but now that I’ve discovered Soylent, I’m healthier than I’ve ever been, have more freedom with my time and money, and never have to worry about the stuff. Finally, I can have my cake and eat it too.

Update: Getting way more responses than I can respond to individually. Please sign up at Follow up post w/ ingredients here:


What’s In Soylent

There is precious little good data in nutrition science. Every study I’ve seen shows poor statistical methods, conflicts with other studies, or does not show statistically significant results, usually all three. It’s a difficult field because there are simply too many variables and the parameters are difficult to control precisely. 

This is why diets are fads. I decided to ditch nutrition and focus on biology. The proportions in Soylent are loosely based off the recommendations of the FDA, though I added a couple extras and changed a few based on my testing. Here is what the body needs.

Carbohydrates (200g): Any molecule consisting only of Carbon, Hydrogen, and Oxygen. Flour, corn, bread, rice, pasta, your cells don’t care. What you need is D-Glucose. The Citric Acid Cycle metabolizes glucose and generates ATP, the cellular ‘currency’ for energy. Carbs can chain together and come in the form of monosaccharides (like lactose), disaccharides (table sugar), oligosaccharides, or polysaccharides, which are very long chains. Short chains get metabolized very quickly, leading to a ‘sugar rush’, and long chains can be difficult to digest. 
I use only oligosaccharides, like Maltodextrin, for Carbohydrates. This mechanism can also metabolize protein and fat, but the brain can only use Glucose for energy. In fact, the brain uses 25% of the body’s glucose, though it accounts for only 2% of its weight.

Protein (50g): Protein is a very general term. What your body needs is 9 ‘essential’ (meaning the body cannot produce it itself), amino acids: Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalaline, Threonine, Tryptophan, and Valine. Eukaryotes use 21 different amino acids for protein synthesis. The human genome contains approximately 20,000 protein coding genes. It’s a complex system. Without these essentials there are some proteins you will not be able to produce.

Fat (65g): Fat has gotten a bad rap. Without it you wouldn’t be able to absorb some essential vitamins, like A, D, E, and K. Fats are triglycerides, and can be saturated or unsaturated, depending on the bonds within the carbon chain. Fat maintains healthy skin and hair, and cushions the body’s organs. Some fats, though, like trans-saturated fats, are difficult for the body to metabolize, and have been linked to heart disease and obesity. I get all the fat I need, in nearly perfect proportion of saturated and unsaturated, and no trans fats, from olive oil.

Cholesterol(X): Cholesterol is used in cell membranes and intracellular transport. However, the body is able to synthesize it on its own and regulates the rate of production. So, even though the FDA recommends it I feel it’s more of a maximum than a recommendation. Soylent has no cholesterol whatsoever.

Sodium(2.4g): You’ll notice a lot of the elements the body needs are ions. Cells communicate with action potentials, electrical voltage differences which accumulate due to the presence of positive or negative ions. Sodium ions are used to regulate blood volume, blood pressure, pH, and osmotic equilibrium. Sodium and Chloride are conveniently found in table salt.

Potassium(3.5g): Potassium is important in neurological functioning, which is one reason it bothers me practically no one gets a full 3.5g / day. Raw Potassium is extremely reactive, so I use potassium gluconate, C6H11KO7.

Chloride(3.4g): Chloride is a negative ion, formed when Chlorine gets an extra electron. It’s used in metabolism and overall pH balance.

Fiber(5g): Fiber is not digested by the body. It helps maintain a healthy digestive system. My digestive system is quite healthy as the only thing that it has to get rid of is the fiber itself.

Calcium(1g): Strong bones and teeth! Also used in muscle operation and the electrical system of the heart. Very important. I consume Calcium Carbonate, CaCO3

Iron(18mg): Iron is used by Hemoglobin in the blood to efficiently transport oxygen. Iron deficiency is one of the most common nutritional deficiencies. If you are a vegetarian I recommend taking a supplement. I dissolve iron chellate in fat separately before adding it to the mixture. 

Phosphorous(1g): Part of the structural framework for DNA and RNA. I use monosodium phosphate.

Iodine(150ug): Constituent of Thyroid Hormones, which regulate basic metabolic rate through gene transcription.

Magnesium(400mg): Another ion, used by many enzymes to catalyze reactions. Be careful, magnesium overdose is very unpleasant.

Zinc(15mg): Used by enzymes in transcription factors, which control the expression of select genes.

Selenium(70ug): Used in some amino acids and the Thyroid gland. Careful, can be toxic in large doses.

Copper(2mg): Used in electron and oxygen transport.

Manganese(2mg): Similar to selenium, used as a cofactor in many enzymes.

Chromium(120ug): Occurs in trace amounts in many foods. Though no certain biological role has been found, there have been reports of chromium deficiency. Just being safe here, may be fine without it, though.

Molybdenum(75ug): Used in the active site of many enzymes. Interesting fact: a shortage of molybdenum held back eukaryote evolution for 2 billion years. Make sure you get your molybdenum, and continue evolving.

Vitamin A(5000IU): Used by the retina of the eye to produce a metabolite necessary for both low-light and color sensitivity.

Vitamin B6(2mg): Or, pyrodoxil phosphate, is a coenzyme for many reactions and macronutrient metabolism.

Vitamin B12(6ug): Key to the normal functioning of the brain and nervous system. Like iron, difficult to obtain from plants so a supplement is suggested for vegetarians.

Vitamin C(60mg): Or, ascorbate, is a reducing agent in many enzymatic and some non-enzymatic reactions. Don’t want to get scurvy.

Vitamin D(400IU): Needed for the internal absorption of calcium and phosphate. Can be synthesized by the body from cholesterol given enough sunlight, but is essential in most people.

Vitamin E(30IU): Several functions including antioxidation, gene expression, and neurological function.

Vitamin K(80ug): Post-translational modification. Once a protein is transcribed, it folds (which is a very important problem we don’t understand well) and modified by factors such as Vitamin K which affect its final utility.

Thiamin(1.5mg): Used in thyamine pyrophosphate, a coenyzme in the catabolism of sugars.

Riboflavin(1.7mg): Required by a class of proteins called ‘flavoproteins’. It’s used in the cofactors (non-protein substances that bind to proteins) FAD and FMN.

Niacin(20mg): Niacin binds to and stimulates a certain membrane receptor, GPR109A, which inhibits fat breakdown in adipose (stored fat) tissue. This decreases the amount of free fatty acids in your blood.

Folate(400ug): Folate itself is not used by the body, but its derivative tetrahydrofolate, and a few others, are used in DNA synthesis and repair.

Biotin(300ug): Another coenzyme, used in the synthesis of a few macronutrients.

Panthothenic Acid(10mg): Used to synthesize coenyzme-A (which itself is used in the synthesis and oxidization of fatty acids), as well as metabolism.

Extras not considered essential:

Lycopene(500ug): Essential in some plants for photosynthesis, it is abundant in red plants like tomatoes and carrots. Lycopene is an effective antioxidant and there is preliminary evidence it has an effect on cardiovascular health, diabetes, cancer, and others. Also, not very scientifc, but the males in my family have always loved tomatoes. I wonder if this is because lycopene has an unusually positive effect given our genetics. The only other nutrients in tomatoes are Vitamin A and C, which I get plenty of.

Omega-3 Fatty Acids(750mg): Humans cannot synthesize these fatty acids, and though links with cancer have been largely debunked, there is limited evidence consumption of these substances improve cardiovascular health and inhibit cognitive aging.

Ginseng(50ug): Used in old folk remedies, limited evidence suggest a link with sexual health and lower fatigue.

Gingko Biloba(100ug): Consumed since antiquity in China and Japan, has limited evidence of positive effect on working memory and focus.

Lutein(500ug): A rather small study found that Lutein improves visual function and can inhibit macular degeneration. There is stronger evidence Lutein is linked to the pigmentation of the eye.

Alpha Carotene(140ug): A single study linked this with lower risk of mortality from heart disease and cancer. Couldn’t hurt.

Vanadium(100ug): Limited evidence has a beneficial affect on glucose control.

The body is a complex machine. There are a lot of substances and chemicals required for it’s optimal operation. However, it is also extremely robust. Many people aren’t getting the recommended amount of any of these substances, but the body is able to compensate via complex regulatory systems. 

This hurts in the long run, though. In fact, turning food in to energy is the primary process that ages the body. By giving it only what it needs, and nothing it doesn’t, I am optimistic about the long term effects. The short term effects are already clear.

If you want to make Soylent for yourself, be very careful. We’re not making pie here. It’s a lot easier to overdose or underdose with the raw elemental form than it is with food. It took me a while to arrange sources for all of these substances, as well. 

You can get many micronutrients from a simple multivitamin, but their contents vary widely. For others such as K, P, Ca, Mg, check your local lab supply store or university. I actually got a lot of mileage out of brewing stores as well.

I am reticent to provide exact brand names and instructions because I am not fully convinced of the diet’s safety for a physiology different than mine. What if I missed something that’s essential for someone of a different race or age group? 

Also, the cost is low but some of the ingredients are hard to find and/or must be purchased in bulk which can be an investment, and some of my suppliers are quite small and would have their stock depleted if many people rushed to purchase the exact same item I did. I think it makes more sense to test this more thoroughly, and then produce it at scale.

So…I’ll just ship you some of my batch. If you are willing to consume exclusively soylent, and get a CBC, chem panel, and lipid blood test before and after the week and share your results with me it’s on the house. 

Bonus points for getting a psych evaluation before and after. The brain is an organ. I can ship it worldwide but it would be nice if you were in San Francisco so we can meet in person.

Soylent is available to purchase on