Understanding the Science of Eating and Happiness

A look into the complicated relationship between what we eat and how we feel.

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It’s the subject of extensive inquiry, yet with each new finding, the science of food and happiness grows increasingly complex. Expert opinion on which diet is “healthiest”—Paleo, Mediterranean, Non-Diet—varies and often conflicts; no wonder we don’t have a clear understanding of how what we eat affects how we feel.

Why does sugar make us feel giddy and terrible? If we want to feel better, are carbs our friend or foe? Should we mainline bananas because they’re serotonin-rich? Ultimately, how does what we eat really impact our happiness?

To supplement our own research, we spoke to an expert on the matter, Elizabeth Somer, MA, RD, who has written several books on the subject, including Food & Mood and Eat Your Way to Happiness. Somer confirmed the little knowledge we already knew to be true: What we’re putting into our bodies has a profound, holistic impact on our emotions.

“There has been a growing body of evidence, both animal studies and human studies, to support that we really are what we eat, physically and mentally,” she said. “And, that makes sense considering that the only place where the brain gets its building blocks is from the diet.”

Although we cannot say we’re even close to fully understanding the subject, below are several illuminating facts we’ve gathered regarding the complicated relationship between mood and food.

Your Brain Is a Pleasure-Seeking Machine

In her book Hungry Brain, Dr. Laura Pawlak points out that our brains have been hardwired to focus on survival, with the “pleasure-seeking circuitry” of dopamine-producing neurons constantly primed for activation by any sign of food (smell, sight, memory).

We’re innately pleasure-seekers, and studies like this one have shown that certain foods—such as sugar, salt, and fat—are potent natural reward-drivers. This reaction occurs because they trigger the release of key “pleasure” neurotransmitters—such as dopamine—more than their healthy counterparts. Ever felt your mouth water at the sight of pizza, but not kale? You already know.

By seeking pleasure, our brains are also seeking survival.

Why does this happen? The answer reaches back to our ancient hunter-gatherer origins: Our brains are programmed to seek life-sustaining sustenance—energy-rich, calorically dense foods (read: pizza, not kale)—that will keep us satiated until the next famine. By seeking pleasure, our brains are also seeking survival.

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But the days of feasting and famine are over. Food is in abundance, with the most “pleasurable” kinds readily available, easily digestible, and often very affordable. These ultra-pleasurable foods are the exactly the ones you might imagine: salty fries, greasy burgers, candy bars, et al.

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Photo: FoodFitnessFriends

So, our brains reward us for consuming stuff that we’ve come to understand is “bad” for us—but that’s not the full story.

Pleasurable Foods Don’t Necessarily Make Us Happy

David A. Kessler, author of The End of Overeating: Taking Control of the Insatiable American Appetite and former head of the FDA, has a name for these calorie-rich, easily digestible foods: They’re hyperpalatable, meaning that they not only go down easy, but they’re engineered to make you want to eat more by triggering a powerful reward conditioning stimulus.

If this sounds like addiction, it is—researchers have found chemical similarities (and similar brain activity) between overeating and other addictive behaviors (doing drugs, gambling, drinking). In an interview with The New Yorker, Dr. Kessler remarked, “Conditioned hypereating works the same way as other ‘stimulus response’ disorders in which reward is involved, such as compulsive gambling and substance abuse.”

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To put it in research terms: One Princeton University study found that rats not only became addicted to sugar, but exhibited signs of withdrawal and anxiety when they were unable to consume it. 

Here’s the ultimate irony: By seeking these pleasure foods, we’re actually not getting happier. Studies illustrate that women who eat diets rich in “Western” foods—namely “processed or fried foods, refined grains, sugary products, and beer”—are more likely to be depressed than their healthier-eating counterparts.

Rats not only became addicted to sugar, but exhibited signs of withdrawal and anxiety when they were unable to consume it.

In The Atlantic, writer Robert Lustig takes the argument further, arguing that pleasurable foods are actually the source of our unhappiness. Discussing the effects of sugar, he writes, “In fact, pleasure and happiness might just be opposites. As we have spent the last 30 years pursuing sugar for pleasure, we have become most decidedly unhappy.” Seen Super Size Me? Enough said.

Bottom line: Food that brings us pleasure does not necessarily bring us happiness.

No, You Can’t Just Eat Serotonin

So what food, scientifically, can make us happy? We decided to begin with our own (misguided) science and reasoning.

Serotonin, also known as the “happy” neurotransmitter, is clearly an important facet of food and happiness. Lack of serotonin has been extensively linked with depression, and there are many well-known anti-depressants, such as Prozac, that specifically aim to raise levels of this neurotransmitter. Let’s also add tryptophan into the mix, which is a key amino acid in the creation of serotonin (without it, serotonin cannot be produced). It’s widely recognized for its high concentrations in protein-rich foods, such as turkey.

serotonin and dopamine Understanding the Science of Eating and HappinessPhoto: High Fat Fitness

Logic would suggest that we eat as many foods as possible that contain high levels of both serotonin and tryptophan. Unfortunately, it’s not that simple. Somer notes, “Only an all-carb snack will boost levels of tryptophan, which can then be converted to serotonin.” High-protein foods, she counters, actually block tryptophan—the key to serotonin creation—from entering the brain. Here’s why:

When you eat a protein-rich meal, you flood the blood with both tryptophan and the other 20+ “competing amino acids,” creating a free-for-all where they all fight for entry into the brain. A protein-rich food supplies tons of competition, which means tryptophan loses out. Only small amounts make it through the blood-brain barrier, little serotonin is made, and you miss out on the needed mood boost.

While turkey or any other protein-rich food won’t give you a serotonin high, carbs will. Once starch is digested, a flood of carbs enters the blood, which triggers the release of insulin, a hormone from the pancreas. Insulin returns blood sugar levels to normal and ushers many amino acids into the tissues. But insulin ignores tryptophan, leaving it behind in the blood. With the competing amino acids gone, tryptophan is the only one standing in line at the blood-brain barrier. It has a straight, unhindered shot into the brain.”

Given that we need carbohydrates to produce serotonin, is the secret to happiness the bread bowl? Maybe not.

Remember: Carbs Are Complex

Assuming that carbohydrates appear to be the “golden ticket” to serotonin production, why have they gotten such a bad rap?

It’s a polarizing question, to be sure. On one hand, you have research from people like Dr. David Perlmutter, author of Grain Brain: The surprising truth about wheat, carbs, and sugar; your brain’s silent killers, who strongly advises against carb consumption entirely. This isn’t simply because carbs could give us a muffin top—rather, he believes that carbohydrates are seriously detrimental to our brains (and, hence, our happiness).

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In The Atlantic’s December 2013 story on Perlmutter, he argues, “Most grain foods, whether we’re talking about quinoa, amaranth, the very popular grains of the day, the reality is they still are associated with a carbohydrate surge. They have a fairly high glycemic index, meaning that after 90 to 120 minutes, your blood sugar is going to go up, and that is detrimental to the brain.”

The list of detriments, according to Dr. Perlmutter, reads like a horror show of maladies: Alzheimer’s. ADHD. Anxiety. Depression. Inflammation. Leakiness of the brain-blood barrier. These are certainly not the results of a happiness-engineered diet. But Paleo life doesn’t seem all too cheery, either.

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Supporters of the opposite viewpoint include Drs. Richard and Judith Wurtman, whose research suggests that carbohydrates are key to keeping us both happy and sane. Dr. Judith Wurtman’s The Serotonin Power Diet showcases years of research at MIT, arguing that carbohydrate-derived serotonin is critical to not only our mental health, but for our physical wellbeing. Strategic carb-based snacks are the way to happiness, Wurtman believes, and can even be used as a tool for weight loss.

So, which side do we take? It’s complex—quite literally. Complex carbs—those that take the body longer to break down—are the best way to incorporate serotonin-producing foods into your diet without causing major spikes in blood sugar. Plus, we’ve never been ones for total deprivation.

Your fat brain needs fat

Our brains are composed of about 60% fat and need to be fed accordingly. Fats are critical to our brain’s ability to function, as well as our moods.

Somer explains, “Each of your 100 billion brain cells is encased, like a balloon, by a sheath or membrane made up of two layers of fat. Through that membrane, the cell gets rid of toxins, takes up nutrients, and sends and receives messages. The more fluid or flexible those fatty membranes, the better they relay and transport information. The less flexible, the more our thought processes are jammed and mood plummets.”

Of course, this physiology doesn’t mean integrating slabs of brie into your daily lunchtime ritual is the right approach (sorry, guys). A specific kind of fat, Omega-3s (also known as “good fats”), are critical structural fats that go straight to tissues in the brain and are exceptionally flexible. That’s why the brain loves them, says Somer.

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Aside from assisting with brain functionality, research such as this Yale University study has found that Omega-3s (namely DHA, one of the key fatty acids in the family) are linked to a reduction in depression. In The Hungry Brain, Dr. Pawlak cites that DHA deficiency is also associated with a decreased number of receptors for serotonin, dopamine, and norepinephrine—all very important good-mood neurotransmitters.

Some Omega-3 rich foods include wild salmon, walnuts, and avocados. Eat ‘em and smile.

Eat Well Today for Happiness Tomorrow

Eating healthfully not only keeps our bodies in better condition to handle illness, aging, and stress, but it can make us happier people in the long run. Research shows that the effects of eating well do not appear as immediately; in other words, they’re not the immediate surge of glee we get from downing a doughnut. It’s crucial to take the long view.

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A study by Penn State psychologist Dr. Helen Handy, cited in The Atlantic, looked at how food and mood played out across several days; how we feel on day three correlates to what we ate on day one. Her findings showed that increased consumption of calories, sodium, and saturated fat resulted in negative moods two days later. This similar study pointed out that men and women who ate vegetables one day felt better the next.

Moreover, this study (cited earlier) concluded that women who ate diets filled with things like processed foods, refined grains, and sugary products were more likely to show depressive symptoms over time than their “modern” diet counterparts, who ate a diet rich in vegetables, lean proteins, and red wine.

If you’ve had a rough day, try eschewing the brownie for an apple—it might make you feel better in the long run.

What Is the Happiness Diet?

Unfortunately, there is no catchall diet for individual happiness (we’re not robots here, and there are other factors at play beyond what we eat). Along with exercising regularly and not smoking, consistently eating well is critical, according to Somer. She adds, “You can’t add blueberries to an otherwise bad diet and expect to feel better.”

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Some of the foods Somers recommends:

  • colorful vegetables and fruits
  • 100% whole grains, nuts, legumes
  • small amounts of extra-lean meats
  • low-fat or nonfat milk products

As for key vitamins, minerals, and acids, she recommends foods rich in vitamins B6 and B12, which aid in building serotonin and maintaining insulation around nerve cells to help brain cells divide properly, and magnesium, to curb cortisol levels when stressed.

Our advice: Eat your vegetables, embrace healthy fat as your brain’s friend, and next time you find yourself grumpily reaching for that chocolate cake—think again.

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