Capital is Sufficient (Part 3): Calories and Nutrients

Today I am continuing my examination of whether or not capital is the binding constraint for meeting humanity’s needs. The prior post looked at our needs for oxygen and water.

Calories. To power our bodies, adults need between 1,500 and 3,200 calories per day, a need we mainly meet by eating and drinking. The best way to obtain calories, however, is surprisingly poorly understood – the mix between proteins, lipids and carbohydrates is subject to debate.

Eating food is the primary solution to our need for calories. This is where Malthus expected the big shortfall to come from. Agriculture simply wouldn’t be able to keep up with the growth in population. The big breakthrough that he didn’t anticipate was the Haber Bosch process of nitrogen fixation, which powered the so-called green revolution. Equipped with artificial nitrogen fertilizer, agricultural output soared. 

The other big win in agriculture was the use of machinery. Today in the US only 1.3% of the employed population works in agriculture and the entire food supply system at $1.1 trillion represents only 5% of total GDP. Even in countries that are further back in development such as India, the percentage of the population engaged in farming has been shrinking, a decline made possible by the availability of sufficient physical capital.

Now clearly not everyone has access to enough calories to meet their needs. For example, starvation is ravaging Yemen right now as a result of the ongoing war there. Overall, however, since the 1970s the incidence of death from famine has been at historic lows. And even before that as Amartya Sen and others have documented many famines resulted from a failure to distribute food, not an absolute lack of it (with examples of rotting supplies in harbors while people starve nearby).

Here too though we cannot rest on our accomplishments. The biggest risk to humanity’s ability to meet everyone’s need for calories is the climate crisis which is disrupting the relatively stable weather patterns required by agriculture. So far we have been experiencing crop failures only locally and sometimes regionally. A global large scale crop failure would result in starvation as we have very limited stockpiles.

Nutrients. The body cannot synthesize all the materials it requires, including a couple of fatty acids, some amino acids, as well as a few vitamins and minerals – these are called “essential” and must be obtained as part of our nutrition. This is another area that is surprisingly poorly understood, meaning that the actual mix and amount of required nutrients we need to take in seems unsettled.

Nutrients, while important, are needed in relatively small amounts. For example, the daily recommended amount for alpha-linolenic acid (ALA) is between 0.5g and 1.6g. The biggest intake requirements are the essential amino acids, with adults probably needing about 7g daily of Leucine as one example. For minerals and vitamins we are talking about even smaller amounts. These are mostly in the milligram and microgram range with the exception of Calcium, Chloride and Sodium, which are needed in a few grams each.

The cost and capital required to produce all of these essential nutrients has been declining substantially over time as a result of scientific and engineering progress. For example, we have recently figured out how to grow rice that has more Vitamin A in it, called Golden Rice. More than half the global population eats rice daily and so having it deliver enough Vitamin A is a major way of ensuring sufficient amounts of that essential nutrient are available.

Here too, capital is not the binding constraint today. But as the example of Golden Rice shows, it will continue to be important to innovate so as to better meet nutrient needs for everyone and not just those who can currently afford to buy every possible supplement by walking into the nearest drug store. Further research is also required to understand which nutrients we really need and in what dosage for humans to thrive and live long, healthy lives.