snack \ˈsnak\ (n) – a small amount of food eaten between meals

As I’ve pointed out before, snacking makes you both fat and weak. And as the beginning of “Eat Like A Predator” states, much of the purpose of a paleo diet is to let you avoid snacking entirely:

Predators gorge and fast; prey grazes.

Rephrased for modern humans: Predators eat meals, prey grazes on snacks. This means you need to eat meals which will carry you through to your next meal, but that won’t make you tired or sleepy.

So why is it so difficult to stop snacking? Why is snack food so uniquely addicting? Why can we demolish entire tubes of Pringles, boxes of donuts, trays of chocolates, and bags of goldfish crackers, when we would never finish the same number of calories in the form of meat and vegetables?

It’s because snack food is a magic trick, played on our senses of taste.

Note: This article will help you understand what’s behind the concept of “food reward” that’s been making the rounds lately.

How Our Tastes Evolved: Understanding The Basic Tastes

Our tastes have been selected, over millions of years, to enjoy foods that are nutritious for us, and to dislike foods that are poisonous or not nutritious. Any humanoid whose tastes were not in accordance with healthy eating—for instance, an inability to distinguish plant toxins, or a lack of preference for calorie-dense fat over lean protein which we have a limited ability to process—would have died out over the hundreds of thousands of generations that separate us from our quadrupedal, forest-dwelling ancestors.

Here’s an excellent discussion of our taste receptors and their probable evolutionary purpose, adapted and modified from this intriguing article: “Why Did We Evolve A Taste For Sweetness?” by the Drs. Jaminet:

The five basic human tastes are sweet, salty, sour, bitter, and umami. Each taste detects either a nutrient class we need or toxins we should avoid.

• Sweet: sugars. Mother’s milk, sweet fruits. Possibly also hydrophobic (fat-associated) proteins, i.e. a fat sensor: it’s impossible to taste fat by itself because it won’t bond to taste receptors.
• Salty: electrolytes. Sodium and potassium are necessary for life.
• Sour: acids. Attractive in small doses (wild fruits, lightly fermented food), aversive in large doses (spoiled food high in bacterial fermentation products).
• Bitter: toxins. Again, usually OK in very small doses (e.g. cruciferous vegetables) but aversive in large doses.
• Umami: glutamate (and some nucleotides). Basically a protein sensor.

(More information.)

Modern Technology, Paleolithic Tastes

The key to understanding snack food is to understand what foods were available to us in the Paleolithic, so that we can understand what our tastes are for. It’s impossible to overdose on sour or bitter because they’re aversive in large doses, so that leaves us with sweet (which also helps detect fat), salty, and umami.

Let’s examine fat: there was no such thing as “vegetable oil” (actually seed oil) in the Paleolithic. The only year-round source of dietary fat was animals, with nuts a secondary, seasonal source. Therefore, our taste for fat is primarily a taste for animal fat—including all the fat-soluble vitamins (A, D, E, K2-MK4) found in animal fat, and for which fat is necessary to absorb.

Sweetness was limited by lack of availability. Paleolithic fruits were much smaller and more bitter than modern varieties, which have been bred for sweetness and seedlessness to the point of being unable to reproduce without human help—and they would not have always been available at their peak of ripeness, as they’re eaten by many other animals too. Honey has always been rare. And as the Drs. Jaminet note, it is entirely possible that sweet taste receptors do double duty as animal fat detectors.

Salt was difficult to obtain, except for those who lived near the ocean. And as Parmesan cheese and kombu dashi hadn’t yet been created, umami was limited to its natural source—meat.

In conclusion, we can see that our taste receptors are primarily geared towards obtaining fatty meat and salt, with nuts and sweet fruit as occasional bonuses. So it’s not surprising that we enjoy salty, fatty meat and sweet fruits.

Snacking: The Supernormal Stimulus Of Taste

“Supernormal stimulus” is a technical term for something that’s so much better than reality that we prefer it…

…even when it’s obviously fake.

Niko Tinbergen and Konrad Lorenz found many examples of this in animals. Mother birds prefer to incubate fake eggs made of plaster if they’re larger and more brightly colored than their own eggs. Male stickleback fish will attack anything with a red underside, including toy boats.

This is because, in the evolutionary history of birds and sticklebacks, there haven’t been enough curious ethologists with plaster eggs and red-bottomed toy boats to make it important for these animals to tell the difference. If it’s egg-shaped and in your nest, sit on the biggest one, because it’s most likely to survive. If it’s in the water and red underneath, attack it, because it’s most likely another male.

Humans are no exception: we’re vulnerable to supernormal stimuli, too. Photoshop gives men rippling abdominals and women exaggerated curves. Comic book heroes are just as unrealistic as the heroines. Round yellow smiley faces communicate emotion more clearly and simply than a picture of a smiling person.

And in the evolutionary time of humans, there hasn’t been enough refined sugar, seed oil, and MSG to make it important for us to tell the difference between them and real food.

Here’s a startling experiment: rats prefer saccharine and sugar to intravenous cocaine, even after previously becoming addicted to cocaine:

PLoS ONE. 2007; 2(8): e698.
Intense Sweetness Surpasses Cocaine Reward
Magalie Lenoir,# Fuschia Serre,# Lauriane Cantin, and Serge H. Ahmed*

“…From day 7 onward, rats sampled lever C [cocaine] almost maximally, though slightly less than lever S [saccharin], before being allowed to make their choices (Fig. 1c). Thus, despite near maximal cocaine sampling, rats under the S+/C+ condition acquired a preference for lever S as quickly as rats under the S+/C- condition.”
…
“Our findings clearly demonstrate that intense sweetness can surpass cocaine reward, even in drug-sensitized and -addicted individuals.”

Characteristics Of Successful Snack Food

If you were to design a profitable and successful snack food, you’d want it to have several characteristics:

• It would be made of cheap ingredients, allowing a high profit margin.
      Since our government heavily subsidizes industrial grain production, you’d make them of grains and grain products…corn, wheat, and soy. Mostly corn, because it’s so heavily overproduced that we’re forced, by law, to feed it to our cars!
• It would be shelf-stable and require no preparation, so that it could be kept without refrigeration, taken anywhere, and eaten at any time.
      Therefore, you’d make it out of highly-processed ingredients that are shelf-stable, pump it full of preservatives so that it could survive for months in a vending machine, and enclose it in lots of disposable packaging so it wouldn’t get damaged in transit.
• It would concentrate the tastes we’ve evolved to enjoy far beyond their natural amounts, and as much as our technology allows.
      This would be the supernormal stimuli of fatty, salty, umami, and sweet: MSG, crystalline sugar, seed oils, fruit juices, “natural and artificial flavors”.
• Finally, it would not be satiating.
      No matter how much you ate, you would never be satisfied.

In other words, you’d create a movie set: something that looks like reality, but even better. More scenic, more exotic or mysterious or futuristic, more dramatically lit…

…and completely, utterly fake. The buildings have no interior, everything in the distance is just a matte painting or computer graphics, and it’s all built as cheaply as possible because it only has to last until the scene has been shot. All a movie set has to do is look nice for a few minutes, or a few seconds, from the right angle. You can’t live in a movie set, because that’s not what it’s built for…

…and you can’t live off snacks, because that’s not what they’re made for either.

The Magic Of Snacks, Part I: Taste Without Nutrition

Just as a movie set’s only constraint is to look good for a few seconds from a limited set of camera angles, a snack food’s only constraint is to taste good until it slides down your throat.

And that’s what technology allows us to do: create products (“snacks”) that tickle our taste receptors far more than real food can ever hope to—but that don’t come with the nutrition that selected us to crave those tastes in the first place.

This is the reason that the concept “eat whole foods, minimally processed” is generally sound: if whole foods taste good to us, it’s most likely because they contain nutrients we need, not because they’ve been engineered to tickle our taste buds. (Note that all modern fruits are heavily engineered products of thousands of years of careful breeding: read Dan Koeppel’s fascinating book “Banana” for a look at one typical example.)

The Magic Of Snacks, Part II: Taste Without Satiety

A pleasing taste isn’t enough to make an addictive snack food: as mentioned above, it must also be non-satiating. Steak and eggs are delicious—but we don’t have the urge to eat them until we’re sick.

There are many parts to satiety, but I’ll touch on what I believe to be the most important issue: protein satiation.

Protein Satiation

Complete protein is satiating. Our bodies absolutely require complete protein—but they also have a limited capacity to process protein in excess of our requirement. This shows up as what’s called “protein leverage”: people tend to consume food until they’ve ingested about 360 calories worth of complete protein. All other things being equal, if we eat foods high in protein, we consume less calories, and if we eat foods low in protein, we consume more. (You can read more about this issue in this AJCN article, and here.)

“Protein” is just chains of amino acids. “Complete protein” is protein containing all the essential amino acids—the ones we must eat because our bodies can’t make them—roughly in the proportions our body needs them.

Interestingly, egg protein is the standard by which protein quality is measured—probably because it takes the same kinds of protein (and other nutrients, like cholesterol) to make a healthy chicken as it does to make a healthy human. Any dietary advice that tells you to avoid eggs for any reason is, by definition, wrongheaded.

Therefore, if we want to sell an addictive and non-satiating food, we should keep it very low in protein (e.g. candy, cookies, potato chips). If it does contain protein, that protein should be incomplete—deficient in at least one essential amino acid—since the limiting factor for protein utilization is the least abundant essential amino acid.

Guess what? Corn and wheat, the foundation of chips, crackers, cookies, and over 90% of the breakfast aisle, are both deficient in lysine. And both zein (corn protein) and gluten (wheat protein) are prolamins, which are very difficult for our digestive enzymes to break down and decrease the digestibility of the associated starch.

Trivia fact: corn gluten meal (CGM) is used as an herbicide. Yum!

In support of this theory, you’ll note that “energy bars” are more satiating than candy bars, despite having a similar taste and number of calories…most likely because they tend to contain some amount of complete protein. (Though they make up for it by costing twice as much. You could be eating prime rib for what energy bars cost per pound. Think about it.)

Fat: The Satiety Potentiator

Fat is not satiating by itself—but it increases the satiation of the protein it’s eaten with. This is because fat slows gastric emptying and increases GI transit time. (More information here.) This is one reason why we can eat entire tubes of Pringles, but only a few eggs: Pringles contain fat and carbohydrate, eggs contain fat and complete protein.

Unless, of course, you’re Cool Hand Luke…

In support of protein satiation, a large hard-boiled egg contains about 75 calories, so that superhuman (and fictional) feat would involve 3750 calories’ worth of eggs. A can of Pringles contains about 900 calories.

50 eggs is just over four dozen eggs…3750 calories is just over four cans of Pringles. What’s easier to eat…a dozen hard-boiled eggs, or a can of Pringles?

The Nutrient Leverage Hypothesis

We can take the protein leverage hypothesis even farther, by extending it to other necessary nutrients. The unjustly neglected blog Fat Fiction makes the startling claim that nutrient deficiency is responsible for the obesity crisis, and cites (among other sources) an intriguing double-blind, placebo-controlled study of feeding multivitamins to obese Chinese women:

International Journal of Obesity (2010) 34, 1070–1077; doi:10.1038/ijo.2010.14; published online 9 February 2010
Effects of multivitamin and mineral supplementation on adiposity, energy expenditure and lipid profiles in obese Chinese women
Y Li1,4, C Wang2,4, K Zhu3, R N Feng1 and C H Sun1

“After 26 weeks, compared with the placebo group, the MMS group had significantly lower BW [body weight], BMI, FM [fat mass], TC and LDL-C, significantly higher REE [resting energy expenditure] and HDL-C, as well as a borderline significant trend of lower RQ [respiratory quotient] (P=0.053) and WC [waist circumference] (P=0.071). The calcium group also had significantly higher HDL-C and lower LDL-C levels compared with the placebo group.”

Anyway, I recommend you read Mike’s “Two Minute Summary”. I’m not sure nutrient deficiency is everything, as he seems to be saying—but I believe he’s got hold of an important piece of the obesity puzzle that has been neglected in the rush to blame everything on insulin, and I encourage others in the ‘paleo’ field to build on his work.

Conclusion: Snacking Makes You Fat, By Design

In conclusion, we can see that “snack food” is designed to make us fat—by giving our taste buds a supernormal stimulus, while withholding the nutrition that has always gone along with that stimulus in evolutionary time. Just like the greylag goose that tries to sit on an egg-colored volleyball, or the stickleback fish attacking a red-painted toy boat, we can’t resist shoving highly processed, brightly packaged non-foods like cookies, donuts, crackers, corn chips, bread, cereal, and candy bars down our throats—

—especially when our rational minds are short-circuited by the label “All-natural!” or “Contains heart-healthy whole grains!” Our livers don’t care if fructose comes from Fanta or apple juice, our pancreas doesn’t care if glucose overload is accompanied by indigestible fiber and plant toxins (“whole grains”), and our eicosanoid pathways can’t tell if they’re clogged with omega-6 fats from Cool Ranch Doritos or Organic Multigrain Rainforest Eco-Chips.

Don’t believe the hype. If it takes multiple layers of brightly-colored packaging and a $multi-million, multi-media ad campaign to sell it, it’s not food. No one has to put meat or eggs in a brightly colored box with a cartoon character on it. I’m just sayin’.

What Should Humans Eat?

Eat foods you could pick, dig, or spear. Mostly spear.

Live in freedom, live in beauty.

JS

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Postscript: For those who want to know more, I explore our mechanisms of hunger and reward in detail in my epic series "Why Are We Hungry?" My older series on carbohydrate addiction starts here and explains some of its pathways.

If you enjoy my articles and want to support my continued efforts to inform and amuse you, my novel The Gnoll Credo is available from Amazon and my publisher in the USA, and from this list of international sellers. You can also make your other Amazon purchases through this link: it’ll cost you nothing, and I’ll get a small spiff. Thanks!