Food is fuel. Every engine needs it to run. Different types of engines use different types of fuel and some fuels are better at doing certain kinds of jobs. But, for most engines, it is problematic, at best, to try to run it on the wrong fuel.
Today, I offer two metaphorical examples of how my own approach to fueling the human engine has changed. The first, and most obvious, as alluded to in the title of this post, is the old-fashioned steam locomotive, that burned coal (or, sometimes, wood) to heat water to produce steam to turn a turbine or push a piston or, in other words, to do real work.
Trains burn lots of fuel because they do lots of work. Today, most trains are powered by diesel-electric motors, with the diesel engine powering the electric motor. In either case, the engines are built to produce maximumly efficient torque for long-duration running times. They are not built to sprint and stop, sprint and stop, sprint and stop.
When you burn coal (or even diesel) there is one primary problem. These are fuels that are fairly hard to start with a match (or a spark). They need a little help in the beginning. For coal, you might start the fire with some sort of kindling. With diesel, you need to pressurize the combustion chamber and have some sort of starter motor that can turn the crank, even under that pressure. In either case, the engine wouldn’t run long or well on just the “kindling” needed to get the fires burning.
Sometimes, even engines designed to run on more “combustible” fuel, have issues, as demonstrated in the following video.
OK, this car, we might all agree, wouldn’t make a great commuter, not unless you’ve got a trained monkey to sit up in the open engine compartment with that can of ether as you roll down the road. But, humorous as that image might be, that’s roughly equivalent to how many, if not most, Americans fuel their own “metabolic engines”, from one Snickers bar to the next.
I’ve been somewhat critical of the classic food pyramid in recent posts and this is the reason. All carbohydrates are more akin to kindling than coal. That doesn’t mean you can’t fuel your engine that way, but it takes an enormous amount of really conscientious effort to both maintain such an engine or to get much real work done.
One major problem we have today, is that there’s not a lot of “real work” being done; and, by that, I specifically mean physical labor. More and more of us are “trapped” behind desks and computer screens, “travel” on heated leather seats, and ”relax” in front of televisions. The more active among us might get a hike, a little gardening, or a little basketball game in on the weekend, but even our ”recreation” has become increasingly passive.
How do you fuel engines tasked like that? Well, frankly, it is under these circumstances that relying solely on ”kindling” can become even more problematic. For one thing, it is quite easy to start too big a fire with kindling (think of those lovely pancake breakfasts with gobs of maple syrup), which burns really hot for a brief time, leaving nothing but ash in short order.
Fueling like this is, at best, in the human body, akin to flooding a gas engine, which is why so many folks get really, really tired after a big meal laden with carbohydrates. At worst, it can also lead to premature detonation, backfires, flaming carburetors, carbon deposits and, often as not, running empty 30 miles from the nearest gas station.
After decades of propaganda, most of us habitually afraid of fat, which is the best analogue we have for “coal” as a human fuel. We are particularly afraid of animal fats, trimming away every little bit of it from our dinners and breeding new animals to be as lean as possible.
The irony here is that - it should be intuitively obvious - the human engine is designed, even optimized, to run, to one extent or another - specfically on animal fats. Don’t believe that statement? What fuel do you think you’re using if/when you’re trying to lose weight? What do you think all that fat on your very own body is supposed to be there for? That’s your long-term, between meal, overnight, and emergency fuel tank.
The anti-animal-fat propaganda campaign really geared up, I believe, with the development of new industrially manufactured vegetable fats….the sorts of products that are profitable for big corporations, notably Proctor and Gamble, who introduced the world’s first hydrogenated vegetable (cottonseed) oil, under the Crisco label, in 1911.
In order to popularize this highly profitable product, it was absolutely necessary to wean people (pun intended) away from the standard of the day, readily available rendered pig fat (lard), which Crisco was specifically designed to imitate and replace.
P&G’s media campaigns of the day adroitly exploited the wave of distrust in the animal products industry at the time, popularized by Upton Sinclair’s famous novel “The Jungle” and creation of one of the first ever progressive institutions: the Food and Drug Administration. But, ultimately, Crisco was largely successful in that it was an affordable alternative to lard.
Unfortunately for P&G, the Pandora’s box that they opened has ended up backfiring on them over time. Nutritional studies began taking note of the detrimental effects of high fat diets. Of course, almost universally, these dietary fats were largely comprised of these new industrial fats, aka “not your great-grandmother’s fat”. Only recently, has anyone really stopped to ponder whether humans were ever designed to consume such things as hydrogenated cottonseed oil.
But, this, of course, has always been the problem of science, especially nutritional science, which has never been quite capable of holding a single opinion on anything for very long. The problem, really, is one of context, often inappropriate equivalence (i.e. all fats are not the same), and unsuccessful attempts to control for a whole host of uncontrollable and unknowable factors.
Take this (reasonably recent study’s) revelation about fats, for instance: “One of the most interesting aspects of these findings is the implication that our time-honored focus on fat saturation may tell only part of the story….Now it appears that the actual structure of the individual fat molecule is critical (emphasis mine -HT), that is, the specific location of individual fatty acids, particularly saturated fatty acids, on the glycerol molecule as consumed seems to make a difference on downstream metabolism of fat and glucose…”
Let me translate and cut to the chase: We know that fats provide essential nutrition and, yet, that these man-made fats appear to be killing us. Well, duh. As it turns out, the typical combination of simple carbohydrates and these psuedo-fats have turned out to be particularly lethal. And, given the propensity of such “science” to turn to ever more patentable and profitable solutions, I’m not greatly encouraged by what they will give us next (can anyone say “olestra“?).
So, in the face of this, I can’t help but wonder, “was there really anything wrong with the “original” McDonald’s french fry…the one cooked in beef tallow? Probably not, at least in modest quantities. But, the one they offer today, cooked in some new-fangled industrial psuedo-fat, mostly to appease the ostensibly ”health conscious” – and vegetarians, of course - in our midst? Probably still lethal, but hey, that’s just a guess.
So, the obvious question is, then, how much fat or carbohydrates or protein do we need in our diet. Well, I’ll defer, again, to the engine metaphor and suggest that, “it depends”, mostly on the kind of work we’re doing. But, in any case, we do need fat and are designed to run really well on it.
At the risk of diverging from today’s topic, I’ll provide one more example that I think is useful: dairy products. There are many nutrition experts that suggest that this too should be minimized, again mostly due to the fat content. Here’s the puzzle, then: if dairy is so bad for us, why is it that all of us (presumably mammals) were specifically designed to be fed with it, at least for some period of time shortly after our birth?
We’ll just leave for another day questions regarding whether or not milk (or other dairy products) are appropriate fuels beyond infancy or whether milk from various non-human animals is similarly optimized for our use.
Let’s just take as fact that, during infancy at least, human (mother’s) milk – as opposed to any other analogue – is an ideal food source. On this basis, we might expect to derive 52% of our calories from fat, 42% from carbohydrates, and – wow – only 6% from protein. interestingly, human breast milk changes in it’s relative ratio of carbs-to-fat over the course of normal feeding, having more carbohydrates in the earliest stages and more fat in the later stages.
By contrast, whole cow’s milk, for what it’s worth, provides 46% of its calories from fat, 21% from protein, and 33% from carbohydrates. It is also worth noting that, since it is – at the very least – impractical for most of us to breast feed beyond infancy (at the very least, I said) – cow’s milk is the most likely dairy we’ll turn to. There may well be evidence that such milk ought to be minimized in our diets or, better yet, consumed in reduced-lactose fermented forms, but, as noted above, we’ll get to that at some point in the future.
The real point here is that, insofar as human milk provides us with any guidance, we are perfectly capable, possibly even optimized, to be fueled with saturated fats comprising perhaps 50% or more of our caloric intake. Yes, there are important roles for each of the other macro nutrients, but minimizing fat in the diet (as most “experts” strongly espouse) is typically accomplished through a trade-off with carbohydrates, which is still a sort of kindling fuel, really, and, unsurprisingly, likely to create a whole range of problems in your typical “engine”.