Sunday, April 22, 2007

Caloric Intake, Relatively

It's difficult to consume the recommended amounts of vitamins, minerals, and other nutrients on a daily basis. It's even more challenging when few calories are consumed, whether by choice or necessity. The rule-of-thumb is 1200 ... go below 1200 calories/day (1500 for men) and there's a good chance that intake of essential nutrients will suffer.1

Take potassium (K). The Adequate Intake for this mineral, for both men and women, is 4700 mg/day.
  • 1 medium baked potato with skin gives you about 926 mg (161 calories). You'd have to eat 5 of them (805 calories) to get 4700 mg K. No butter.
  • 8 oz. of 2% milk gives you about 366 mg (122 calories). You'd have to consume 12.8 cups of milk (1562 calories) to get 4700 mg K. There are 16 cups in a gallon.
  • 1 medium banana (7-8 inches) gives you about 422 mg (105 calories). You'd have to eat 11 of them (1155 calories) to get 4700 mg K.
  • 8 oz. tomato sauce gives you about 811 mg (59 calories). You'd have to eat (drink?) about 6 cups (354 calories) to get 4700 mg K.
That's just one nutrient. Add vitamins A, D, E, K (different K), C, Bs, all the minerals, the essential fats, fiber, and an increasing number of phytochemicals and you're juggling with the best of them. (I wasn't boosting my argument by listing foods that are poor sources of potassium. The above, along with dried fruits, are excellent sources.)

Potassium is one of those nutrients that help maintain a healthy blood pressure. Those at risk for high blood pressure include the overweight and obese, people for which it's not a bad idea to trim calories. Oh, the conundrum.

Of course you can meet the daily requirements for the basic nutrients. You just need to pay attention to what you eat. That task is easier when you're eating more food.

This led me to wonder just what an Average American consumes in a day, in calories, and how that compares to years previous.

Here's an average caloric intake for Americans, provided by the Centers for Disease Control (CDC), for the years indicated:

Click for larger.

Ok, how about a few decades prior to that?
"During 1971- 2000, a statistically significant increase in average energy intake occurred. For men, average energy intake increased from 2,450 to 2,618 kcals, and for women, from 1,542 to 1,877 kcals."
Trends in Intake of Energy and Macronutrients - United States, 1971-2000
OK, how about a few centuries prior to that?

Here's a Figure I scanned from The Structures of Everyday Life, Civilization & Capitalism, 15th-18th Century, by Fernand Braudel:

Click for larger.

It attempts to depict graphically a size and distribution of caloric intake for Europe during the 16th-18th Centuries. It shows an intake for Swedish nobility of between 5078 and 6406 calories, an intake for 17th century Pavia (Northern Italy/Switzerland/Southern France/Austria) of between 4446 to 7217 calories. And an average intake for Spanish seafarers of 3422 calories. Parisians in the late 18th century were eating about 2300 calories/day.

It's not a fair comparison, since America today is populated by a diverse group of not only Europeans but Asians, Africans, Native Americans, and others with unique historic eating patterns. Also, as the Figure states, the calculations were based on meals of the privileged (and at least in the case of the Spanish sailors, likely men). But in my reading, that 2300 for Parisians pops up in other places:
"In 1800, the English population consumed a little more than 2,000 calories per day..."
This particular author cites this as a risk for malnourishment:
" ... At this level, historians have estimated that roughly 20 percent of the adult population was too malnourished to work. Of the 80 percent available for work, most could not have worked at anything like the intensity of the modern [year 2001] workplace."
- John H. Coatsworth, What Food? Who Eats It? Why Does It Matter?
(Mr. Coatsworth's workplace is surely more hopping than mine.)

Are American women malnourished (1970-2000: 1524-1877 calories)? Perhaps not calorically, but as I discussed at the beginning of this post, maybe nutritionally.

Let's go back even further:
"Low serum cholesterol levels and the absence of obesity could be interpreted as signs of chronic starvation, yet hunter-gatherers had higher daily caloric intake than Americans do and with much higher energy output. The normal activity levels associated with this high-through-put status produce high levels of aerobic and muscular fitness and contribute to the low prevalence rates of chronic degenerative diseases that hunter-gatherers generally exhibited."
- Melvin Konner, Evolution and Our Environment. Will We Adapt?
"Archaeological evidence suggests:

Prehistoric hunter-gatherers appear to have enjoyed richer environments and to have been better nourished than most subsequent populations (primitive and civilized alike). ...

Whenever we can glimpse the remains of anatomically modern human beings who lived in early prehistoric environments still rich in large game, they are often relatively large people displaying comparatively few signs of qualitative malnutrition. ...

Archaeological evidence suggests that specific deficiencies - including that of iron (anemia), vitamin D (rickets), and, more controversially, vitamin C (scurvy), as well as such general signs of protein-calorie malnutrition as childhood growth retardation - have generally become more common in history rather than declining."
- Mark Nathan Cohen, Health and the Rise of Civilization
I'm hardly a historian. I can't offer perspective on whether the above accounts are romanticized. I'm sure prehistoric hunter-gatherers had their caloric down times. These examples are representative however of my returns from a cursory search on Google.

What this all tells me is that a healthy diet is one that keeps calories and nutrients plentiful, and the expenditure of those calories equally high.
1 This is not a minimum number of calories needed to sustain an individual's basal metabolic rate, which is different for each person. This is only a number likely to support intake of the DRIs (RDAs).

1 comment:


As a practitioner of Paleolithic nutrition I enjoyed your post. If one condenses the time line (2 million or so years) of mankind to a single year, agriculture came just yesterday. Which means, our bodies, for the most part, can't process well "Neolithic" foods. Our Paleolithic ancestors ate fatty meat, eggs and wild fruits and vegetables. Emphasis on FATTY meat.