This piece was co-authored with Margaret Leitch, Phd

In a nutshell, this is what Stone Age people thought about their nutritional requirements:


This approach to eating kept enough of them alive until they could procreate so eventually you could order pizza on your iPhone while watching Stranger Things on Netflix.

And because of technology, eating has become a lot more complex than roasting over an open fire something you stalked, stabbed, and skinned yourself. Like your buddy Grug, who had the misfortune to turn his back on you during the last famine. Also, bugs. Mmmm … bugs.

It used to be all about survival. Any calories would do, much to Grug’s misfortune. Jiminy Cricket’s too. Nowadays, your long-term survival is more dependent upon what you don’t eat. Because just as most of us have evolved to handle things like grains, legumes and dairy just fine (suck it, paleo), our environment has gone through significant evolution as well. In the modern world, we’ve changed from eating to survive to eating for pleasure. We adapted from viewing food as a source of life to seeing it as entertainment for our tongues.

Coupled with a desire to spend less time in preparation and instead embrace convenience, the world got fatter.

I know that there are those who believe viewing “food as fuel” is wrong, and make strawman arguments about how anyone who thinks of it that way isn’t capable of seeing food in any way other than fuel, missing out on all that important “information” that food contains. But I defend both thinking about and promoting viewing food primarily as a source of fuel for one’s body. My reasoning has a lot to do with the innate human desire for simplification.

To begin with this defense of seeing food as fuel, let’s bullet point some info to provide perspective of the world we live in:

  • According to the National Center for Health Statistics, in the U.S. almost 70% of adults are either overweight or obese.1
  • In the last half century, the amount of American food dollars dedicated towards eating out has risen from 25% to 49%.2
  • According to a Center for Disease Control survey, fewer than a quarter of Americans consume the recommended minimum of five servings of fruit and vegetables each day.3
  • According to a Gallup poll from 2012, 46% of Americans don’t believe in evolution.4

Why did I show that last one? Well, not believing in evolution reveals a lack of scientific literacy. In other words, a lot of people will look at the wealth of nutrition information available to us and see Greek.

People are overweight, they eat out too much (which means they eat too much heavily processed food that is high in fat, sugar, salt and calories), they don’t eat enough fruits and vegetables and they’re not big on science. So, simplifying things for them is logical, especially when you consider that there is a lot of research to show that the more complex a diet or health regimen is, the lower the adherence rates are.5

And so, let’s expose the strawman. When you refer to food as fuel it does NOT mean that you dismiss all the things that food is and does. It does not mean that you see fuel as the only story about food. Rather, it’s a way of communicating food to people who desire simplification of eating in a way that they can relate to and follow.

Hang on; we’re going to get all science-y on your ass.


A Calorie is a Calorie, But Not All Are Equal

I’m going to quote an article by Dr. David Katz, director of the Yale Prevention Research Center, who I interviewed for my and Margaret’s book. Despite the fact that he has some disturbing opinions in regards to alternative medicine, I have found him to still be wise when it comes to nutrition and weight loss. Dr. Katz said a calorie is a calorie the same way a mile is a mile. These are units of measurement, but they can still be different: “A mile is a mile. But walking one over flat ground when well-rested feels very different from climbing one up a mountain when exhausted.”6

And different calories feel different too, which brings us to …


Your Brain On Food

Have you seen Trainspotting, that movie about heroin addiction? It’s a serious bummer and I don’t recommend it.

There’s a scene in which a woman injects the drug for the first time and she says … well, I won’t write what she says. Anyway, she suggests that heroin is way better than sex. I’ve not tried heroin, so I can’t weigh in on the debate, but it does make me wonder what kind of lame lovers she’s had.

Why all this talk of heroin? Because although the degree is far less, highly palatable food hijacks your brain’s reward system in the same manner.7 (NOTE: This does not mean it’s addictive.)

Think of an apple. Imagine taking a big bite. Even if you love apples, you can’t imagine eating six of them at once, right? Because no matter how good they are, it’s not as though your mouth just had an orgasm, is it?

Crème brûlée, though? Or cookie dough ice cream? Or “Mmmm … I love Turtles”? Total mouthgasm.

Unlike a real orgasm, however, junk food doesn’t offer much of an afterglow. Plowing through half a pizza or a box of chocolates may make you feel good for a few minutes, but that feeling doesn’t stick around for the rest of the day. A sexual romp can keep you sated for a long time, but junk food begets more junk food: you keep eating well beyond the point of bodily energy requirements, losing track of how much you ate and being unable to tell whether you’re still hungry. Why do you do this? Because the reward is outstanding. Before you know it, the compulsion grows, and you need ever more sugar, salt and fat to quench the desire for the next mouthgasm.

I’m going to stop writing that word now, okay?

Evolution programmed us to like certain flavors. One of the reasons we like sweetness is that it represents nutrition. A piece of fruit is at its nutritional peak when it’s at its sweetest. For the millennia of human evolution, seeking out sweetness was good – until technology started messing with things and making nutritionally vacant yet calorically dense hyper-flavored sugar-fat combination treats like hot fudge sundaes. What’s more, such foods are soft rather than crunchy, allowing for a fast ingestion that generates an immediate sense of pleasure. It seems similar to the difference between smoking heroin and injecting it.

Have you ever had a perfectly ripe mango? It’s one of the most amazing-tasting natural foods on the planet. One mango has about 130 calories. How many can you eat? I’ve tried to eat more than one in a sitting, but halfway through the second I didn’t want any more. Something in my brain shuts down so a second one doesn’t seem that appealing, no matter how good the first one tasted.

Compare that with a high-sugar/high-fat restaurant dessert such as the Keg’s carrot cake à la mode. It has 2,344 calories. That’s 18 times as many calories as a mango. I know I would eat the whole thing and then lick the plate clean; the flavor is so overwhelming that all appetite control is lost. (Then I’d have to do a full marathon worth of running to burn it off. Think on that math.)

So what the hell is going on here? It’s neuro-chemistry. Sugar, fat and salt all create a chemical cascade in your brain, an intricate interaction of hormones, neurotransmitters, endorphins, satiety signals and reward sensations. Mangos are a simple taste of natural sweetness – delicious, yes, but we get bored with it quickly. Processed treats, on the other hand, amplify and combine flavors to create an overwhelming taste sensation that’s hard to get tired of.

What we’re talking about here is basic operant conditioning psychology related to the stimulus-response model of behavior change. If a stimulus (such as putting a chocolate bar into your mouth) elicits a positive response (such as thinking, Whoa, Mama, that tastes good), the stimulus behavior is reinforced and you seek out that rewarding feeling again and again. It works the other way as well, where a bad taste is seen as punishment, causing you to avoid foods you don’t like.


Hedonic vs. Homeostatic Eating

It’s all about the hippopotamus.

Wait, what? Oh, sorry. Hypothalamus. My co-author Margaret insists it’s the hypothalamus, and she would know, because of the PhD in neuroscience psychology something something.

There is much recent research about the metabolic and neural feedback signals that are responsible for our desire to eat.8 Many of these are generated in the hypothalamus, which is like a thermostat for your body. It regulates internal temperature, hunger, thirst and sleep cycles.

So far, so good. If hunger were just a matter of hypothalamic inputs, the brain could hypothetically adjust our appetites to keep our bodies in a healthy weight range; it could stop us from eating when we’d had enough to meet our daily energy requirements.

But that ain’t happening.

Our ability to regulate food intake “cannot withstand the strong environmental pressures in most individuals,” said Hans-Rudolph Berthoud, neurobiology of nutrition professor at the Pennington Biomedical Research Center in Louisiana. “Our brain is designed to strike a balance,” Nicole Avena told me. “But our brain can sense if we’re deficient in nutrients. It’s possible to be overfed but undernourished.” At least, it’s been possible in the past century. Junk food provides a lot of calories but little nourishment. For most of human history we didn’t have this problem; things are now out of balance. “And the brain is still seeking out those essential nutrients, so it sends out more hunger signals to get them. There is a cognitive element to getting the vitamins and nutrients we need.”

Runaway food consumption is a breakdown between two systems that drive eating. One is physiological, called homeostatic hunger.9 It regulates your body’s need for sufficient calories to maintain homeostasis.10 In less scientific terms, it’s about fueling your daily energy requirements, and not much else.

The other system is psychological, called hedonic hunger. Think of the word hedonism. It’s all about the pleasure, baby.

Physiological hunger – the kind that keeps weight “normal” – is guided by signals sent from the gut, blood and hypothalamus sensing levels of glucose and amino and fatty acids.11 If you are experiencing this type of hunger because your body needs food, just about anything is going to taste good.

I remember being out for a run once and “bonking,” which is a runner’s term for, Oh God need food now feel wretched can’t run without food please feed me. I made it back to my car ready to eat the steering wheel and found a prehistoric granola bar that my wife had left in the glove box. I don’t dig granola bars, especially ones whose best-before date are from around the time a baby Justin Bieber burst out of an alien torso, but I wolfed that sucker down as if it was the antidote to fast-acting poison, and it was scrumptious.

On the other side of the equation, psychological hunger – eating for pleasure – arises from a chain of events that start in the middle of the brain, and that bitchin’ vibe you get from eating something sweet and fatty hits those same reward paths as drugs, alcohol, gambling and even sex.12 This is about cravings. You don’t need to eat this tasty food, but you want it.


Going Against Gut Instinct

Time for a reality check: your body has no wisdom when it comes to food.

Some alternative practitioners speak of the “wisdom of the body,” and hold that humans have an inherent system designed to seek out only the nutrients we need.

Did anyone else just hear a flock of ducks go by? Quack, quack, quack …

If this was the case, we’d have a kale shortage and childhood obesity would not exist. The only things the body – and brain – respond to immediately are sugar, fat and salt. This is because each of these compounds produces an immediate signal to the brain, telling it that they hold value: energy to allow for movement (like hunting for more food and procreating) and to build up fat stores to survive the next famine.

Salt, of course, is an exception in that it doesn’t contain calories, but it is nevertheless critical to survival.13 It’s important for brain development, and the salt that’s sweated from our bodies also needs replacing. Food companies have used it liberally to make their products taste better and promote additional consumption.14

In short, the body wants what it wants, and it does not have a magical mechanism for obesity prevention. Neither do dogs, by the way, animals that are suffering their own obesity crisis and will eat chocolate with abandon even though it is toxic for them. Canine bodies have no more wisdom to prevent obesity than human bodies do. Obesity rates prove that our tastes are pretty basic, and in this land of constant plenty, most of us are going to gain weight.

There is no magic mechanism, but there is consciousness. And this is where separating fuel-based eating from pleasure-based consumption is valuable.


Fuel vs. Pleasure

It’s a simple story: choose foods that fuel performance more often, and choose ones that are eaten purely for pleasure less often. Indulgence is fine, sometimes. I do not advise a life of constant dietary deprivation. Look at a tasty treat, understand how many calories it contains, and decide if it’s worth it.

It doesn’t take long for people to get an idea of what fuel-based eating is. Simply telling them to focus on foods that are not highly processed / refined helps a lot. It becomes pretty easy to recognize the difference between apples vs. applesauce, tomatoes vs. ketchup, oranges vs. orange juice, kale vs. kale chips, steak vs. Big Macs, potatoes vs. French fries, cherries vs. Cherry Coke, chicken breasts vs. McNuggets, grilled salmon vs. fish sticks …

Getting people to stop and ask the question, “Does this fuel my body to a higher level of performance, or is it something eaten mostly for pleasure?” is a powerful tool that should not be so readily dismissed. It’s not complex, which makes it a lot easier to follow than micromanaging one’s diet, and as I already pointed out, higher diet complexity = lower adherence.


Separating Fly Shit from Pepper

A little while ago I wrote an article telling people to stop worrying so much about separating fly shit from pepper and just focus on the important stuff instead of getting obsessive over micro details of diet and exercise.

There was a question I asked in the article: “Do you get all waxed, tanned, oiled and Speedo-ed and pose on stage? Do you have a rippling six-pack and are questing for the shredded eight-pack? Do you have the job of protecting your quarterback’s spleen from being ripped out by some behemoth defensive lineman? Do you regularly step into a ring and need to hit people so hard their grandchildren are born dizzy?”

And then I quoted my friend and nutrition expert extraordinaire Alan Aragon: “The fitness & nutrition world is a breeding ground for obsessive-compulsive behavior. The irony is that many things people worry about simply have no impact on results either way, and therefore aren’t worth an ounce of concern.”

Precision in the world of nutrition can be a valuable thing, especially if you’re a competitor or if you’ve tried the big picture approach and it doesn’t work for you. Some people need the hard rules, the in-depth planning and the micro tracking.

But some don’t. Some get confused and/or burned out by such attention to detail, such as with tracking macronutrient intake, for example. Some need simple rules to follow. Some just create a basic story of what is good fuel and what is eating for pleasure, and that is what works for them. If I obsessed over my diet, I might actually have rippling six-pack abs. I might also be miserable. So I don’t obsess, and settle for drifting in and out of having a four-pack. Four-pack abs are about the best I can usually sustain at 48 years old.

And that’s good enough for me.



Food is fuel, and a lot of other complicated science-y nutrition stuff that goes beyond it being fuel. But for most of us, we can interpret “fuel” to be “rocket-fuel-go-juice” that motivates us to make healthier, less processed choices instead of highly palatable indulgent ones based on pleasure seeking. Such an approach also has the benefit of being more satiating and less likely to induce high caloric consumption, which is a major benefit to weight loss and weight maintenance.

And such an approach is a lot better than what the majority of the developed world is doing. This is what makes viewing food as fuel as being worthwhile.


Read the comments here.

Follow James on Facebook and Twitter.

James S. Fell is an internationally syndicated fitness columnist for the Chicago Tribune and author of Lose it Right: A Brutally Honest 3-Stage Program to Help You Get Fit and Lose Weight Without Losing Your Mind, published by Random House Canada. He also interviews celebrities about their fitness stories for the Los Angeles Times, and is head fitness columnist for and a regular contributor to Men’s Health.



  1. National Center for Health Statistics, “Health, United States, 2012: With Special Feature on Emergency Care,” Hyattsville, MD. 2013. Table 23, p. 205.
  2. Jeanine Stein, “Americans May Be Running Up the Calorie Count When Dining Out,” Los Angeles Times, February 22, 2010.
  3. Center for Disease Control and Prevention, “Surveillance of Certain Health Behaviors and Conditions Among States and Selected Local Areas — Behavioral Risk Factor Surveillance System, United States, 2007,” February 5, 2010. (Accessed November 28, 2013.)
  4. Frank Newport, “In U.S., 46% hold creationist views of human origins,” June 1, 2012. (Accessed November 28, 2013.)
  5. Alan Delamater, “Improving Patient Adherence,” Clinical Diabetes, 24, no. 2 (2006): 71-77; Leslie Martin et al., “The challenge of patient adherence,” Therapeutics and Clinical Risk Management, 1, no. 3 (2005): 189-199; Juta Mata et al., “When weight management lasts. Lower perceived rule complexity increases adherence,” Appetite, 54, no. 1 (2010): 37-43; Juda Mata et al., “Keep it on: How complex diet rules prevent weight loss,” Appetite, 50, no. 2-3 (2008): 562
  6. D. Katz, “The Calorie: Excess heat, too little light,” Huffington Post, March 22, 2012. (Accessed November 28, 2013.
  1. Nicole M. Avena et al., “Evidence for Sugar Addiction: Behavioral and Neurochemical Effects of Intermittent, Excessive Sugar Intake,” Neuroscience and Biobehavioural Reviews 32, no. 1 (2008): 20–39; Nicole M. Avena, “Sucrose Sham Feeding on a Binge Schedule Releases Accumbens Dopamine Repeatedly and Eliminates the Acetylcholine Satiety Response,” Neuroscience 139, no. 3 (2006): 813–20; P. Rada et al., “Daily Bingeing on Sugar Repeatedly Releases Dopamine in the Accumbens Shell,” Neuroscience 134, no. 3 (2005): 737–44; Nora D. Volkow et al., “Overlapping Neuronal Circuits in Addiction and Obesity: Evidence of Systems Pathology,” Philosophical Transactions of the Royal Society of London B Biological Sciences 363, no. 1507 (2008): 3191–200; Gene Jack Wang et al., “Brain Dopamine and Obesity,” Lancet 357, no. 9253 (2001): 354–57; Nora D. Volkow et al., “Reward, Dopamine and the Control of Food Intake: Implications for Obesity,” Trends in Cognitive Sciences 15, no. 1 (2011): 37–46.
  2. C. Konturek et al., “Neuro-Hormonal Control of Food Intake: Basic Mechanisms and Clinical Implications,” Journal of Physiology and Pharmacology 56, Suppl 6: 5–25; R.E. Nisbett, “Determinants of Food Intake in Obesity,” Science 159, no. 820 (1968): 1254–55; G.N. Wade and I. Zucker, “Development of Hormonal Control over Food Intake and Body Weight in Female Rats,” Journal of Comparative Physiology and Psychology 70, no. 2 (1970): 213–20; Hans Rudolph Berthoud and H. Munzberg, “The Lateral Hypothalamus as Integrator of Metabolic and Environmental Needs: From Electrical Self-stimulation to Opto-Genetics,” Physiology and Behavior 104, no. 1 (2011): 29–39; Hans-Rudolph Berthoud, “Interactions between the ‘Cognitive’ and ‘Metabolic’ Brain in the Control of Food Intake,” Physiology and Behavior 91, no. 5 (2007): 486–98; A.P. Coll et al., “The Hormonal Control of Food Intake,” Cell 129, no. 2 (2007): 251–62; M.O. Dietrich and T.L. Horvath, “Feeding Signals and Brain Circuitry,” European Journal of Neuroscience 30, no. 9 (2009): 1688–96; A.P. Coll et al., “The Hormonal Control of Food Intake,” Cell 129, no. 2 (2007): 251–62.
  3. Lowe and Butryn, “Hedonic Hunger”; Lowe and Levine, “Eating Motives”; John E. Blundell and Graham Finlayson, “Is Susceptibility to Weight Gain Characterized by Homeostatic or Hedonic Risk Factors for Overconsumption?” Physiology and Behavior 82, no. 1 (2004): 21–25.
  4. Lowe and Butryn, “Hedonic Hunger”; Lowe and Levine, “Eating Motives.”
  5. Kent C. Berridge, “Building a Neuroscience of Pleasure and Well-being,” Psychology of Well Being 24, no. 1 (2011): 1–3; John E. Blundell et al., “Resistance and Susceptibility to Weight Gain: Individual Variability in Response to a High-Fat Diet,” Physiology and Behaviour 86, no. 5 (2005): 614–22; N. Pecoraro et al., “Chronic Stress Promotes Palatable Feeding, Which Reduces Signs of Stress: Feed Forward and Feedback Effects of Chronic Stress,” Endocrinology 145 (2003): 3745–62.
  6. Blum et al., “Sex, Drugs, and Rock ’n’ Roll: Hypothesizing Common Mesolimbic Activation as a Function of Reward Gene Polymorphisms,” Journal of Psychoactive Drugs 44, no. 1 (2012): 38–55; Berridge, “Building a Neuroscience of Pleasure and Well-being”; W.A.Wilson, “The Role of Learning, Perception and Reward in Monkeys’ Choice of Food,” American Journal of Psychology 72 (1959): 560–65, Berridge and Robinson, “Parsing Reward.”
  7. A. Cocores, “The Salted Food Addiction Hypothesis May Explain Overeating and the Obesity Epidemic,” Medical Hypothesis 73, no. 6 (2009): 892–99.
  8. ibid.