EARLIER this year Asda was among a number of British supermarkets shamed because some of their beef products were found to contain horsemeat. Luckily, consumers are a forgiving lot. Asda reported last week that its sales have already recovered to pre-scandal levels. Brands have recovered from worse. Take "Soylent Green", a dystopian science-fiction film set in 2022, in which the eponymous nutritious wafer is unveiled as containing recycled humans. Now, nine years early, a product called Soylent is about to hit the shelves in America.

Its creator, Rob Rhinehart, a 24-year-old computer scientist, assures Babbage that his version of Soylent contains no human flesh. In fact, Soylent promises to be as tasteless as its name, comprised as it is mostly of powdered starch, milk proteins, olive oil, oat fibre and various trace minerals and vitamins. When reconstituted with water, Soylent becomes a unflavoured beige liquid. "There are no secrets here," says Mr Rhinehart. Just the quantities of every essential nutrient, as recommended by America's Food and Drug Administration, in their "most economical, bioavailable, water-soluble form".

Soylent is a complete food replacement for those disinclined or too busy to cook, but lacking the wherewithal to eat out. Mr Rhinehart also touts the environmental benefits of not having to travel to the shops, prepare meals or discard spoiled food. Earlier this year he put his mouth where his money is by subsisting solely on Soylent for three months. He claims never to have felt healthier.

That is not to say the process went smoothly. Mr Rhinehart is no nutritionist and early versions of Soylent had their problems. Omitting iron from his original formula made Mr Rhinehart’s heart race and an absence of sulphur caused joint pain, while (deliberate) overdoses of potassium and magnesium resulted in cardiac arrhythmia and burning sensations. He currently lives on Soylent during the week and enjoys conventional food at the weekend.

“I wanted everything that could go wrong with Soylent to happen to me first,” he explains. Seven recipes later, he believes it is ready to for wider consumption. A crowdfunding effort on his website has raised nearly $300,000 so far, with thousands of people signing up for either a week’s or a month’s supply of the stuff, due for delivery in August. There are plans afoot for male- and female-specific formulae, as well as a vegan version. “If we raise a lot, we could put money into formal testing and research,” says Mr Rhinehart.

Adam Drewnowski, director of the Centre for Public Health Nutrition at the University of Washington, will not be among them. “To some extent, Soylent is an expensive glass of milk,” he says. While Soylent’s $65 weekly price-tag is certainly cheaper than eating out, it compares unfavourably with the cost of cooking for yourself. America's Department of Agriculture recently calculated the weekly cost for a family of four to eat a thrifty but healthy diet at home as $146, even allowing for some spoilage.

Mr Drewnowski is also sceptical of Soylent’s environmental credentials. He notes that the bulk of food’s carbon footprint and greenhouse-gas emissions come from production and processing, rather than distribution, cooking or waste. Mr Drewnowski calls the carbon impact of Soylent’s milk protein "not insignificant".

Nutritionally complete liquid foods have been around for decades. Examples include milk formula for infants, weight-loss diets like the Cambridge Plan, and medical interventions for people in comas. A French product called Plumpy’Nut, based on peanut butter, provides emergency nutrition for children suffering a famine for less than $10 a week. What makes Soylent different is that it is being aimed at healthy adults who could cook and eat normally but would rather not. Soylent’s crowdfunding success indicates that there is hunger for such fuss-free food. Whether people will want to live by gruel alone in the long run is another matter altogether.