On eating your vegetables, non-compliers, and food reward.
I have always loved food. I was encouraged to love food, and vegetables especially. It was a point of pride to eat them, and more than that, to like them. Why? Because they are presumed good for you, and while doing something good for you is virtuous, liking something good for you is even more virtuous! It is one thing to be willing to suffer for an end, but to want something intrinsically that has a good result — that means you are a naturally good person. That means your instincts are well formed. This is the essence of feeling right for the world, competent, belonging.
Food is one of the first things we are aware of. It's a daily interaction. To parents who want their children to thrive, which, I think, is the usual way of things, seeing a child "naturally" gravitate to actions that will cause them to thrive puts their mind at ease. If you want to please your parents, showing signs that you are naturaly predisposed to take actions that make you healthy works. This is more so the more health-conscious your parents.
And yet this particular example is odd. Consider the effort we go to to "encourage" children to eat vegetables. There are multiple research intiatives and campaigns going on to try to "get" children to eat vegetables . This is because we believe vegetables are health-giving, but at the same time there is a widespread resistance by children against eating them. How could such a trait have possibly evolved?
One reason many children struggle against this adult-imposed mandate to eat vegetables is that it competes in many cases with something more rewarding. It is generally considered healthy for a child to run and play. Do we have to tell children to chase each other, to skip and jump and dance? No. In fact children are notoriously active. It is a challenge to keep them still! However, if they have access to a captivating book, movie, or video game, then they may be less inclined to go outside. Likewise, one reason children may be eating lower quantities of vegetables could be that the alternatives available are more appealing. If those alternatives are sugar or even starch (presugar) or meat, i.e. high quality protein or energy sources, then it stands to reason that children would choose those alternatives instead.
We are wired to seek energy and nutrition in the form of protein. Sugar, starch, and fat are all dense sources of energy which we need. Meat is an excellent source of amino acids which we also need. We are driven to eat these. Vegetables, on the other hand, are relatively nutrient poor. Yes, you read that right. I know that we are lambasted with propaganda telling us how important colourful vegetables are for nutrients, but this is misguided. For one thing, most plant sourced nutrients are less bioavailable than animal sourced alternatives. Individual types of plants are always nutritionally incomplete, and many essential nutrients simply aren't available in the necessary amounts in any normal consumption of plant foods. For another, non-starchy vegetables are poor sources of energy. A vegetable is constructed of carbohydrates. These carbohydrates are either merely "structural", which means made of fibre, and hence indigestible, or they are digestible, meaning they are sugars or starches. If a plant (fruit or vegetable) is high in sugar or starch, it is not usually a challenge to get children to eat them. However, the kinds of vegetables we've been taught to eat for vitamins aren't typically energy dense.
Besides children, there is another relevant class of people. We tend to think of them as people who have never grown up. They're stereotypically men, but of course not always. These people eat what they feel like even when it's not thought to be good for them. They often engage in other activities known to be unhealthy in the long term, such as drinking alcohol to excess, or partaking in other drugs, engaging in risky behaviours such as promiscuous sex or thrill seeking, smoking, and just generally behaving in ways that aren't recommended by health advocates. Why do they do this? Because it feels good! It is gratifying.
We have a reverence for the ability to delay gratification. It stands to reason. The ability to defer or even reject an activity that gives pleasure now in order to get more pleasure later pays off, at least when the calculation is correct. We presume that this ability to delay gratification develops over time as part of "growing up", but we recognise that some individuals never seem to attain much of that ability.
Where this reasoning goes wrong however, is when we erroneously assume we know the long term consequences of a decision. We can be reasonably sure, for example, that not smoking will improve health when accumulated over decades, but not all presumed long-term behaviours are so certain in their effects. The longer the outcome takes to have an effect, the harder it is to learn from one's own experience. In the case of some health behaviours, it takes trust and discipline.
The personality type that tends to gratify now tells us about our brain's pleasure and reward system. Only something that gives us pleasure now would cause us to act in a way that we believe would be detrimental later. These non-compliers don't tend to eat their vegetables. Why? Because vegetables don't give us much pleasure! In fact, they often taste downright bitter and unpleasant unless drenched in a sugar sauce or melted fat. Unlike coffee or beer, this bitterness is not compensated for by desired psychological effects. There is no measurable upside. You can learn to like it, just as you can learn to like coffee or beer, but there is no intrinisic reward. The available rewards are social, or a self perception of virtue. If children don't like vegetables, it is usually because the vegetable is bland or bitter, and it provides no physiological reward because your body is getting little out of it. This fact can be used to form hypotheses about behaviours we evolved to do through the pleasure / reward mechanism.
It is true that many vegetable have vitamins in them, but with very few exceptions (e.g. salt), we do not seem to be driven by micronutrient needs much, in the way we are for protein and energy . In contrast to foods high in energy, which activate brain reward systems, or high in protein, which satisfy hunger, an item like broccoli doesn't seem to even register as food, even when hungry . While you may have heard stories about cravings for chocolate indicating magnesium deficiency, the one study that I know of that tested that refuted it . Explaining chocolate cravings with a need for magnesium seems like the worst kind of self-delusional rationalisation. It's ok to just give yourself permission to eat chocolate, if that's what you want.
That we aren't driven to seek micronutrients is important. It suggests that the foods we evolved on that fulfilled energy and protein needs also provided all necessary nutrients at the same time. Otherwise we simply would not have survived. What foods present during the majority of our evolution that most of us want to eat from a young age without prodding simultaneously contained protein, energy, and necessary micronutrients? Why are we advocating diets so notoriously difficult to balance and so far from our natural inclinations that we actually have to campaign people to get them to eat it?
As reported in
Stephen J. Simpson, David G. Le Couteur, David Raubenheimer,
Putting the Balance Back in Diet,
Cell, Volume 161, Issue 1, 2015, Pages 18-23, ISSN 0092-8674,
"Similar types of experimental design have been used to show that organisms from acellular slime molds all the way to primates possess nutrient-specific appetite systems for macronutrients, such as proteins, carbohydrates, and fats, as well as for at least two micronutrients, sodium and calcium (Simpson and Raubenheimer, 2012). However, most micronutrients do not seem to be specifically regulated; rather, their intakes are maintained within healthy limits by a combination of correlation in foods with other regulated nutrients and non-specific mechanisms such as learned aversion to foods associated with development of a micronutrient deficiency, coupled with heightened attraction to novel foods (Simpson and Raubenheimer, 2012)."
As presented by Stephan Guyenet at the Ancestral Health Symposium 2017. Not yet elsewhere published to my knowledge. See experimental evidence at 13m00 (single subject).
Michener, Willa, and Paul Rozin. “Pharmacological versus Sensory Factors in the Satiation of Chocolate Craving.” Physiology & Behavior 56, no. 3 (September 1994): 419–22. https://doi.org/10.1016/0031-9384(94)90283-6.
"Chocolate craving has been attributed to rewarding effects of phenylethylamine (13) or magnesium (1,2,29). It is clear that chocolate can have neurologic effects because it will induce migraine in susceptible individuals, as will phenylethylamine (23). However, claims for a physiological basis for the causation or satiation of chocolate craving have been criticized on the ground that they are not adequately supported by evidence (31)."
"This is the first experimental study directed at differentiating between physiological or sensory accounts of the satiation of nondrug cravings, using chocolate craving, the most common craving in North America. At the onset of craving, chocolate cravers consumed a chocolate bar, the caloric equivalent in "white chocolate" (containing none of the pharmacological components of chocolate), the pharmacological equivalent in cocoa capsules, placebo capsules, nothing, or white chocolate plus cocoa capsules. Chocolate reduced self-rated craving. The cocoa capsules, placebo, and no treatment conditions had virtually no effect. White chocolate produced partial abatement, unchanged by the addition of all the pharmacological factors in cocoa. This result indicates no role for pharmacological effects in the satisfaction of chocolate craving. It also suggests a role for aroma independent of sweetness, texture, and calories."