Subsisting on Soylent

One of the most epic scenes in cinematic history occurs when Charlton Heston's character shouts out "Soylent Green is People!" at the end of the movie Soylent Green.

Video 1. Charlton Heston exhibiting his acting chops.

Soylent Green is set in a dystopian future (sort of like Elysium) in which overpopulation and Global Warming has created a food shortage. As a result, people are forced to eat rations made by the Soylent Corporation, and their most recent product is Soylent Green which is "a green wafer advertised to contain "high-energy plankton" from the world's oceans, more nutritious and palatable than its predecessors "Red" and "Yellow," but in short supply."

The protagonist in the movie played by Charlton Heston discovers that there is not enough plankton left in the ocean to make Soylent Green, and instead he uncovers the shocking truth: The wafers are made from harvested human corpses. Hence the line "Soylent Green is People!"

Inspired by the movie, Rob Rhinehart undertook a Kickstarter project to replace the solid food in his diet with an all-purpose drink. Mr. Rhinehart cheekily named his product Soylent, which possesses the texture of a smoothie or shake rather than a wafer. Soylent is shipped as packets of powder along with a fish/canola oil blend that you combine with water. To make a full day's supply, you mix 2 quarts of water with one packet of power and one packet of the oil, and then blend the mixture together.

Is it possible to subsist on Soylent alone? The Verge writer Chris Ziegler decided to find out:

"Soylent’s spokesperson told me that they don’t expect most people to adopt a 100 percent Soylent diet, even though you technically can: each day’s packet contains roughly 100 percent (give or take a few percentage points) of your daily FDA-recommended allowance of fat, potassium, carbohydrates, fiber, and a selection of 23 vitamins and minerals. But I intended to go all in."

Figure 1. Soylent: Looks more like a chocolate protein shake than people.

For a whole month, Mr. Ziegler consumed no solid food (with the exception of one minor lapse); his diet consisted of the 2 quarts of Soylent each day. The first question that comes to mind is what does Soylent taste like?

"But I was pleasantly surprised. The best way I can describe it is if you put a few tablespoons of peanut butter in a blender and filled the rest up with milk. It was considerably thinner than I’d expected, but still rich, creamy, and strangely satisfying. It had just the smallest tinge of sweetness. And at 38 grams of protein per serving, I wasn’t surprised that it consistently made me feel full."

The second and more important question is how was Mr. Ziegler's health after the one month?

"I fell short of my goal of eating nothing but Soylent for an entire month by five days. The reason was logistical — I needed to save this precious, hard-to-find powder so we could coordinate our video shoot — but I certainly wasn’t broken up about it. I lost about 12 pounds along the way with very little health drama. For the most part, I actually felt great."

Thus from a subjective standpoint, his health self-evaluation was positive i.e. he "felt great." Ideally, we would want a medical professional to check his health before and after the experiment providing more quantitative information such as measurements of his overall energy level, vitality, sleep schedule, resistance to illnesses, etc. For example, a blood test before and after would have been insightful. However the fact he felt fine and even lost a significant amount of weight is a good sign (assuming that he was overweight which appears to be the case from his picture). It is not surprising he lost weight because each serving of Soylent (with oil) contains only 670 calories, or 2010 calories per day.

A third question is how much does Soylent cost?

"What did surprise me was that I never really tired of the flavor of Soylent. I expected that by the end of the first week, I’d be dreading every sip, but I actually fell into a groove where I looked forward to my next glass. And it was nice recouping significant time otherwise spent looking for and eating food — perhaps an hour a day or more. Furthermore, if I was ordering Soylent month to month, I’d be paying $8.50 a day to get effectively all the nutrition and calories I needed to stay alive for the price of a standard New York City lunch."

Soylent is significantly cheaper than buying solid food, and saves time from food preparation and consumption.

A large DIY (Do It Yourself) community has sprung up around Soylent, and hopefully the group includes some medical professionals. There are significant potential risks for those who attempt to subsist on Soylent alone. One possible danger is that 100% of the FDA nutrient requirement may not be suitable for all individuals. Another danger is that perhaps some vital nutrient is missing, which is not likely given what we know about essential nutrients (see below). A third danger is that the chemical and physical diversity of food including its physical form may be healthful in some possibly indirect manner.

Regardless I think Soylent is a big deal, and I look forward to writing more about it in the future. I will end this post with some technical details about Soylent and a list of Essential Nutrients below the fold.

A. List of ingredients:

• Carbohydrates (400 g), in the form of oligosaccharides such as maltodextrin
• Protein (50 g), in a powdered form such as rice protein
• Fat (65 g), in the form of olive oil
• Sodium (2.4 g), from table salt
• Potassium (3.5 g), in the form of potassium gluconate
• Chloride (3.4 g), also from table salt
• Fiber (5 g) 
• Calcium (1 g), in the form of calcium carbonate 
• Iron (18 mg), from an iron chelate 
• Phosphorus (1 g), from monosodium phosphate 
• Iodine (150 μg) 
• Magnesium (400 mg) 
• Zinc (15 mg) 
• Selenium (70 μg) 
• Copper (2 mg) 
• Manganese (2 mg) 
• Chromium (120 μg) 
• Molybdenum (75 μg) 
• Vitamin A (5000 IU)
• Vitamin B6 (6 μg) 
• Vitamin C (60 mg) 
• Vitamin D (400 IU) 
• Vitamin E (30 IU) 
• Vitamin K (80 μg) 
• Thiamin (1.5 mg) 
• Riboflavin (1.7 mg) 
• Niacin (20 mg) 
• Folate (400 μg) 
• Biotin (300 μg) 
• Pantothenic acid (10 mg) 
• Choline, in the form of choline bitartrate 

Non-essential ingredients

• Lycopene (500 μg)
• Omega-3 fatty acids (750 mg)
• Ginseng (50 μg)
• Ginkgo biloba (100 μg)
• Lutein (500 μg)
• alpha-Carotene (140 μg)
• Vanadium (100 μg)

B. Nutrition Facts sheet:

As you can see, each serving (2/3 quart) of Soylent is designed to meet ~33% of the daily requirements for most nutrients so that three servings (2 quarts) would meet 100% of the daily requirements.

C. What are the nutrients necessary for human life?

From the Wikipedia entry on essential nutrients:

"An essential nutrient is a nutrient required for normal human body function that either cannot be synthesized by the body at all, or cannot be synthesized in amounts adequate for good health (e.g. niacin, choline), and thus must be obtained from a dietary source. Essential nutrients are also defined by the collective physiological evidence for their importance in the diet, as represented in e.g. US government approved tables for Dietary Reference Intake. Some categories of essential nutrients include vitamins, dietary minerals, essential fatty acids, and essential amino acids."

1. Fatty acids

• α-Linolenic acid (ALA, 18:3), an omega-3 fatty acid
• Linoleic acid (LA, 18:2), an omega-6 fatty acid

2. Amino acids (essential):

• Isoleucine 
• Lysine 
• Leucine 
• Methionine 
• Phenylalanine 
• Threonine 
• Tryptophan 
• Valine 
• Histidine

Essential amino acids necessary for preterm children but not healthy individuals:

• Arginine

3. Carbohydrates:

Carbohydrates are sugar molecules and chains of sugar molecules. No individual carbohydrate is an essential nutrient in humans. However, carbohydrates are necessary to provide the calories for your metabolic and work activities. Glucose is the basic energy source in the blood, and it can be can be synthesized from amino acids and glycerol, or more typically broken down from the carbohydrates that you ingest. "The two main sources of carbs in Soylent are the starch in oat flour and the oligosaccharide Maltodextrin."

4. Vitamins

• Vitamin A (beta-carotene) 
• Vitamin B1 (thiamin) 
• Vitamin B2 (riboflavin, vitamin G) 
• Vitamin B3 (niacin, vitamin P, vitamin PP) 
• Vitamin B5 (pantothenic acid) 
• Vitamin B6 (pyridoxine, pyridoxamine, or pyridoxal) 
• Vitamin B7 (biotin, vitamin H) 
• Vitamin B9 (folic acid, folate, vitamin M) 
• Vitamin B12 (cobalamin) 
• Vitamin C (ascorbic acid) 
• Vitamin D (ergocalciferol, or cholecalciferol) 
• Vitamin E (tocopherol) 
• Vitamin K (naphthoquinoids)

5. Dietary minerals

• Calcium (Ca) 
• Chloride (Cl−) 
• Chromium (Cr)
• Cobalt (Co) (as part of Vitamin B12)
• Copper (Cu)  
• Iodine (I) 
• Iron (Fe) 
• Magnesium (Mg) 
• Manganese (Mn) 
• Molybdenum (Mo) 
• Phosphorus (P) 
• Potassium (K) 
• Selenium (Se) 
• Sodium (Na) 
• Zinc (Zn)

6. Other:

• Choline (similar to B vitamins)

7. Ultratrace elements [Wikipedia]:

"In biochemistry, an ultratrace element is a chemical element that normally comprises less than one microgram per gram of a given organism (i.e. less than 0.0001% by weight), but which plays a significant role in its metabolism. Possible ultratrace elements in humans include boron, silicon, nickel, and vanadium. Other possible ultratrace elements in other organisms include bromine, cadmium, fluorine, lead, lithium, and tin."