The Hacking of the American Mind
Page 25
Mind over Matter
My UCSF reward-eating team has studied the effect of a twelve-month mindfulness intervention added on to a standard diet-exercise program for obese patients along with a six-month follow-up period.36 Half received just the diet and exercise intervention, while the other half received mindfulness training and the instructions to practice every day for about forty minutes. We were mildly surprised that the mindfulness subjects lost only a small (and not significant) amount of additional weight compared to the control subjects. But the more they practiced mindfulness, the fewer sweets they ate, and the better their blood glucose control, suggestive of improved metabolic health.37 However, when we looked at specific fat depots, we were encouraged to find that the mindfulness group lost a lot of visceral (big belly) fat, while their subcutaneous (big butt) fat remained essentially the same.38
Visceral fat is not like any other fat in your body. While subcutaneous fat accounts for anywhere from 5 to 45 percent of your body weight, visceral fat only encompasses 4 to 6 percent. So when you stand on a scale, which are you measuring? You don’t know. Subcutaneous fat, for the most part, is not metabolically active, and once formed is extremely difficult to eradicate. But excesses of subcutaneous fat do not contribute to poor metabolic health, other than the fact that people who don’t like their bodies experience psychological stress because of it. In fact, subcutaneous or “big butt” fat can actually be protective in some cases. Conversely, it’s the visceral fat that is the driver of the diseases of metabolic syndrome and depression; this relationship has been well documented in adolescents39 and in adults.40
In our UCSF adult mindfulness study, virtually all subjects improved their metabolic health significantly. Fasting insulin, glucose, triglycerides—all reduced over the twelve months and stayed reduced even after the intervention was over.41 These data suggested that mindfulness meditation reduced visceral fat, which in turn improved various health parameters. While no prospective study has yet been done, it’s likely that mindfulness would prevent these metabolic problems from occurring in the first place.
How do we know your propensity to accumulate visceral fat is not just genetic? Well, to factor out other influences, you would have to look at identical twins. A recent study from Finland took ten sets of identical twin adult males who had the same weight and BMI as their twin, the same eating patterns, the same living conditions, etc. The only thing they differed on was leisure-time physical activity. One twin was active, the other a couch potato. The researchers evaluated all their metabolic parameters, all their calories consumed, and finally all of their fat depots.42 In each case, the inactive twin carried about four extra pounds of visceral fat, probably the reason that the inactive twin weighed four pounds more than the active twin. And it was this visceral fat that correlated with their cardiovascular fitness and their fasting glucose and insulin levels. This study shows us clearly that inactivity is associated with increased visceral fat—exclusive of energy intake or genetics or family background or upbringing. And it’s the visceral fat that predicts future metabolic disease. Visceral fat is the most malleable fat depot in the body: it’s the easiest to lose. And it’s the visceral fat that is directly amenable to exercise.43
Exercise Sculpts Your Brain as Well as Your Body
Doctors have known for decades that exercise is the single best thing you can do for yourself, both physically and mentally. Everyone thinks exercise makes you lose weight, yet there is not one study anywhere in the world’s literature that shows that exercise alone causes weight loss: it causes visceral fat loss, but it also causes muscle gain, so the two tend to cancel out, and sometimes body weight even goes up.
The question is: Can exercise treat major depressive disorder? Can it make non-depressed people happier? Many people have heard of the endorphin rise with significant exercise, or runner’s high. Does it open the gateway to happiness as well? Many prospective trials have now been conducted, and the overwhelming majority demonstrate that exercising is better than not exercising; exercise is about as good as SSRIs are in treating depression; and exercise + SSRIs is better than SSRIs alone.44 And it doesn’t matter what kind of exercise; cardio and resistance training both work. One explanation for these findings is that we know that stress increases cortisol, and that cortisol corresponds with decreased cell birth in the hippocampus. We aren’t exactly sure how or why, but greater numbers of cells in the hippocampus is associated with happiness. Fewer cells equals more chance for depression. Exercise both increases the birth of these cells and offsets stress-induced cell death. One of the reasons we think antidepressants work is that they also correspond with new cells being born in the hippocampus. If we somehow negate or squash the growth of these cells, antidepressants don’t work at all.45
Perhaps the most fabled benefit of exercise is the aforementioned runner’s high, the sudden onset of euphoria experienced by hard-core marathoners. This phenomenon has been attributed to the release of the EOP beta-endorphin,46 and more recently we’ve learned that the added benefit of sedation and alleviation of anxiety is due to the simultaneous release of endocannabinioids—our own personal hash stash present throughout the brain—47yet without giving us the munchies.
Well, that’s great if you’re a marathoner. But does exercise work in mere mortals who may be unhappy but not necessarily clinically depressed? Here the data are harder to come by. In large analyses with many subjects, there appears to be a significant effect of exercise on improved mood.48, 49 Even adolescents, who are by nature moody, can benefit from exercise’s effects on mood and depression.50 (Of course, with some kids being perpetually glued to their smartphones or World of Warcraft, they’re getting less exercise now than in years past.) And in a meta-analysis of 1,500 elderly people, exercise was found to be effective in decreasing symptoms of depression.51
But these are research studies . . . and people don’t live in a vacuum. Weather, temperature, wind, and elevation all impact on one’s desire and performance of exercise. A group in China took this on by geo-coding (using these geographic variables) to compare levels of happiness in twenty-eight countries around the world.52 They also adjusted for GDP (see Chapter 12). Their findings showed that, after having adjusted for all the confounders, physical activity correlated with well-being, and lack of physical activity with the greatest unhappiness.
The effects of both meditation and exercise are real, but likely not enough to turn depression into joy. What about combining the two? Might there be additive effects? One short-term study paired both together; first subjects engaged in a forty-minute mindfulness practice, and then they got on a treadmill for another forty minutes, for eight weeks. The results showed that the combination of the two was better at alleviating depression than was either one alone.53
We shouldn’t be surprised that virtually any stimulus that increases psychological stress also inhibits PFC functioning and can ultimately foster addiction, and any stimulus that specifically increases visceral fat will increase the risk for depression. Conversely, anything that can attenuate either of these two phenomena can turn these negative emotions around. All of the above remedies are tried, tested, and guaranteed, or your money back (but since none of them costs any money, don’t expect a refund).
There’s an App for That . . . or Is There?
But here’s where the technology industry will try to get its hooks into you. Many companies and digital app manufacturers have been proffering “personalized” health monitoring and programs in the name of “wellness.” What is wellness, anyway? Most insurance companies define wellness as “the absence of illness,” because for them it’s about not paying benefits: if they don’t hear from you, you must be well. Exercise trainers equate physical fitness with wellness. But what if you’re physically fit but financially destitute? Or what if you’re sleep deprived? Meditation coaches define wellness as a state of spiritual calm or lack of stress. But what if you’re calm because you smoke a few join
ts or take a few drinks to make the world go away? Each person has his or her own definition of wellness. But wellness really means so much more, and contentment is at the top of the list.
These companies will sell you a wearable computer that will do everything from monitoring your step count to monitoring your blood pressure54 to monitoring your blood glucose. They’ll sell you a set of ready meals brought to your door, and buzz you when it’s time to exercise and sleep, and determine for how long you engaged in both. And some people are changing their behavior because of them. There are more than forty thousand smartphone apps on the market devoted to health and fitness. They have digital apps that can monitor your emotional well-being55 and that use techniques such as self-monitoring, providing feedback on performance, and goal setting. Some of these apps are “gamified” with badges and monetary rewards to increase compliance.56 They’ll monitor your mindfulness and provide reminders to walk. You can compete with your friends to get steps in. We’re like Pavlovian dogs, trained to respond to the dings on our cell phones. Clearly a burgeoning cottage industry.
All of this sounds too good to be true. Because it is. Oh, yes, these companies and apps can monitor your every heartbeat and generate lots of data. But do they alter your health or well-being? A systematic review of twenty-seven randomized controlled trials of smartphone apps yielded modest evidence of efficacy, with only half showing benefits.57 Those that improved health tended to do so in conjunction with other modalities (e.g., a trainer or coach). These studies were not very long, ranging in duration from one to twenty-four weeks, with a mean of ten weeks. Only half the studies monitored continued engagement with the smartphone app, and we know that app usage usually falls off at the four- to six-week mark,58 because these apps have yet to learn how to turn data into information that the individual can use. And the lack of actionable data leads most users to eventually curtail their use after time.59 These algorithms are just not ready for prime time.
Back to the Prime Suspect
Stress and sedentary behavior have been around for a while. Yet today addiction and depression are overwhelming public health problems. Now, at long last, we must deal with the most pernicious denizen of our Western environment and culture, the most toxic stress of all. The factor that causes more cases of addiction, depression, disease, and unhappiness than all of the others combined. The toxic brew to which all of America, and indeed, the entire world—old and young, rich and poor, Caucasian and African-American and Latino and Asian, educated and not—is now exposed. The toxic constituent that masquerades as our pal, our “homey,” our BFF. The toxic item that has invaded our homes, our schools, our workplaces, and our bodies, and we willingly open the door: toxic food.
19.
Cook (for Yourself, Your Friends, Your Family)
Which brings us to our final question: How did all of these pathways change in the last forty years? Why are addiction and depression today the number five and six diagnoses, just behind the various diseases of metabolic syndrome (heart disease, hypertension, type 2 diabetes, cancer) that are numbers one through four? Maybe it’s because people who think they aren’t exposed to something actually are? And maybe that exposure is the same across the country and regardless of class? Or around the world? There are many causes, but the one we haven’t yet addressed is the one that is currently affecting almost everyone in the world regardless of class. And what if that exposure is mixed into all of our food without our knowledge? And what if that exposure just happens to be addictive? What’s the cheapest pleasure?
Of course, the answer is sugar—the other white powder. Now you’re thinking, Great, I made it through this entire book, and Lustig is bringing up sugar—again! But, it’s true. Sugar isn’t just responsible for many of our physical health problems, but it also plays a significant role in our mental health. Let me prove it to you. Sugar is the stealth ingredient that’s been added to virtually every industrial recipe to make processed food palatable, and ultimately saleable. As I described in Chapter 6, sugar fulfills the criteria of a substance of abuse, as it is toxic and addictive. It also meets criteria for regulation, as it is ubiquitous (can’t get away from it) and detrimental to society.1 If most of the food in the grocery store is spiked with added sugar, and you don’t know, because there are fifty-six names for sugar on the label and you don’t know them, then how do you avoid it? And if the fiber is removed from fruit to turn it into juice yet no sugar is added, can you even trust the label? And if its biochemical properties fry your liver, and its hedonic properties fry your brain and make you want more, how do you keep from succumbing?
Sweetening the Pot
The American Heart Association has argued for a daily limit of 6 teaspoons of added sugar for adult women, 9 teaspoons for adult men, 3–4 teaspoons for children,2 and none for toddlers below the age of two.3 The World Health Organization and the USDA are more lenient, declaring 12 teaspoons of added sugar per day the maximum. However, American adults consume an average of 19.5 teaspoons of added sugar per day, and children consume an average of 22 teaspoons per day. Latinos, African-Americans, and Native Americans consume between 25 and 50 percent more than their Caucasian counterparts.4 These minorities are at greater risk for developing metabolic syndrome due to their added sugar consumption, especially from soft drinks.5, 6 And we know that these same minorities are higher risk for mortality when they manifest severe mental illness.7 But of course this is all correlation, not causation.
Here’s the conundrum: What if we decided to cut down our personal sugar consumption? What if we consciously removed sodas, candy, cakes, and ice cream—everything we normally call dessert—from our homes and from our diets? Turns out we’d still be over our limit, because only 51 percent of the sugar in our diet is in the foods that you’d expect. That means that 49 percent of the sugar we consume is in foods and drinks that we didn’t know had sugar. Salad dressing, barbecue sauce, hamburger buns, hamburger meat, as well as so-called healthy options, like granola and muesli. And don’t get me started on the health benefits of fruit juice, which is basically just sugar without the fiber. You’re still at risk for diabetes.8 So even if you cut out dessert, you’ll still be over your limit, because of the rest of the sugar that’s in processed food.
The industry argues vociferously that sugar is a required and necessary ingredient in their recipes. Here are a few of the industry’s pro-sugar arguments, and why it’s good for them and bad for you.
(1) Sugar adds bulk. Did you ever wonder why Lucky Charms has marshmallow stars, hearts, moons, and clovers? Because kids like them? Well, yes, but really because marshmallows are cheaper than oats. By taking up space in the box, the industry saves money on oats and can sell the box for more. A great business strategy.
(2) Sugar makes food brown. This is why bananas brown and why we paint barbecue sauce on our ribs on the grill. It’s called the Maillard, or “browning,” reaction. Well, that reaction is happening inside your cells all the time, and when it does, two things happen: proteins unravel, and free radicals form, which further damages cells. The Maillard reaction has another name: the aging reaction. Every time this reaction occurs, it throws off an oxygen radical, which is similar to hydrogen peroxide: it’s great for killing bacteria on your skin, but it also kills liver cells, which is why so many people who have fatty livers progress on to cirrhosis. And fructose causes that aging reaction to occur seven times faster than glucose. Your body, and especially your liver, is aging faster with sugar. Just like it does with alcohol. Not good for your physical or mental health.
(3) Sugar raises the boiling point. This allows for caramelization to occur, which is very tasty, but again this is just the Maillard reaction, which, over time, can cause your cells to age. Now there are data to suggest that fructose could “caramelize” your hippocampus,9 which could remove the brakes from your dopamine transmission, squashing your PFC, your Jiminy Cricket.10
(4) Sugar is a humectant (it attracts and maintains moi
sture). How soon does fresh bakery bread become stale? Maybe two days? How about grocery store commercial bread? More like three weeks. Ever wonder why? In commercial bread, the baker adds sugar to take the place of water, known as water activity, because sugar doesn’t evaporate: it takes up space in the bread, and the sugar molecules hold on to water during baking, so the bread stays moist. Furthermore, the sugar will attract water from the air, so the bread won’t dry out after it’s baked. Good for the industry, bad for your health.
(5) Sugar is a preservative. Have you ever left a soda at room temperature open to the air? Of course, after the carbonation escapes, it goes flat. But do bacteria or yeast ever grow in it? Never.
The question is whether the hit to your liver provided by each dose of sugar is worth the eventual decline in physical health, risk for disability, and increased medical costs. The answer is in: sugared beverages alone account for 180,000 deaths per year worldwide, and for about 10 percent of all disability-adjusted life years.11 And this is especially true in the twenty- to forty-five-year age group, which is experiencing rates of disability like never before.12 And some of that disability is mental health, linked to sugar consumption.13
A Little Less Sweet
My UCSF metabolic team recently completed a study where we took forty-three children (Latino and African-American), aged nine to nineteen with metabolic syndrome, and who consumed at least 50 grams of sugar per day. We studied them on their baseline diet for various aspects of metabolic health and fat in different organs. We then catered their meals for the next nine days to have the same caloric content, the same percentage of protein, fat, salt, and carbohydrate as their usual diet. The only difference was that we substituted starch (glucose) for the added sugar (glucose + fructose) in their diet. We took the sugar in their diet from 28 to 10 percent of calories and kept everything else the same. We substituted bagels for doughnuts, baked potato chips for sweetened yogurt, and turkey hot dogs for chicken teriyaki. We didn’t give them good food; we gave them processed food, but without all the added sugar. We gave them a scale to take home, and each day they weighed themselves. If they were losing weight, we counseled them to eat more, in order to keep them weight-stable. At the end of the nine days of eating our food, we studied them again.14