By 2040, most "meat" will come from alternative sources and not dead animals. That's according to a report led by AT Kearney, a global consultancy firm. 

The basic conclusion, based on interviews with industry experts, is that 60 percent of "meat" eaten in two decades' time will be either lab-grown (35 percent) or plant-based (25 percent). 

Alternative "meats" range from traditional meat substitutes (think: tofu, seitan, mushrooms, and jackfruit) to insect protein (mostly mealworms and crickets) to novel vegan meat replacements, which use hemoglobin and binders to imitate the sensory profile of meat. Cultured meat (aka clean meat, cell-based meat, and slaughter-free meat) is newer to the scene and – at least for the time being – more exclusive, costing $80 per 100 grams as of 2018. It is grown in a lab and only requires a single cell extracted from a living animal, but the end product is identical to conventionally produced meat.

As of 2018, the combined market for plant-based meat alternatives stood at $4.6 billion. That's projected to grow 20-30 percent per annum for the next several years. Cultured meat, on the other hand, is not currently commercially available and is only just starting the process of being accepted by global food regulators, with the US Department of Agriculture (USDA) and Food and Drug Administration (FDA) agreeing to regulate cultured meat jointly for the first time last year.

Nonetheless, the report's authors predict cultured meat will win out in the long-run, securing 35 percent of the market by 2040. In comparison, vegan meat will be "more relevant in the transition phase towards cultured meat". Traditional meat substitutes and insect protein, they say, are less likely to see growth "as they lack the sensory profile to convince average consumers".

One obvious benefit of alternative meats is that they are more sustainable than regular meat. The Food and Agriculture Organization of the United Nations (FAO) estimates close to half (46 percent) of the world's harvest is dedicated to livestock feed. In comparison, 37 percent of agricultural production is food humans consume directly. 

Calorie-wise, a lot gets lost in translation – 1 kilogram of chicken meat, for example, requires 3 kilograms of grain. Considering that 1 kilogram of meat equates to the same number of calories as 1 kilogram of grain, 46 percent of world harvest adds less than 7 percent to the world's available food calories. In comparison, 1 kilogram of vegan meat and 1 kilogram of cultured meat require 1.3 and 1.5 kilograms of arable crops respectively, equalling a 70 and 75 percent calorie conversion rate.

Right now, two big problems are cost and consumer appeal. A 100-gram beef burger costs about 80 cents, whereas a 100-gram vegan meat burger will cost you $2.50 and a 100-gram burger made of cultured meat costs $80. But as technology improves and it becomes possible to produce these foods en masse, costs will likely fall. A 100-gram burger made of cultured meat could cost just $4 by 2031. As for consumer appeal, studies have shown people in Western countries, China, and India are open to the idea.

As the report authors point out, the benefits of alternative meat aren't just environmental. As well as being cruelty-free, they offer advantages as far as product design goes (you could replace fatty acids with omega, for example) and have lower Salmonella or E.coli risks, unlike conventional meat. What's more, there is not the same level of epidemic risk (e.g. bird flu) and production does not require large-scale use of antibiotics, which experts warn could be a huge contributing factor to antibiotic resistance.

If all goes well, it might not just be "fake" meat we see on the market – but plant-based and cultured seafood, leather, silk, egg white, milk, and gelatin too.