The sugar alcohols sorbitol and xylitol are harmless in themselves, but they aren’t absorbed by the body and end up in the colon, where they can draw in fluid and cause diarrhea. This is why they’re only used commercially in small quantities, such as in mints or chewing gum, as opposed to beverages. A related compound, however, erythritol, is absorbed and may have the harmlessness of xylitol without the laxative effect.
Erythritol is found naturally in pears and grapes, but industrially, yeast is used to produce it. Erythritol doesn’t cause cavities,91 and it hasn’t been implicated in fibromyalgia,92 preterm birth,93 headaches,94 hypertension,95 brain disorders,96 or platelet disorders97 like other low-calorie sweeteners. Moreover, erythritol may actually have some antioxidant properties.98 As with any highly processed product, though, its utility should be confined to increasing your consumption of green-light foods. So, for example, if the only way for you to eat half a grapefruit is to sprinkle some sugar on it, then it’s probably better to eat a sugared grapefruit than no grapefruit at all—though sprinkling it with erythritol would be even better. With this logic in mind, I use erythritol to increase my consumption of cranberries (remember my Pink Juice recipe in chapter 8?), cocoa powder (see here), and hibiscus tea.
My Hibiscus Punch
In 2010, an antioxidant analysis of three hundred different beverages was published, examining everything from Red Bull to red wine.99 And the winner is . . . hibiscus tea! I documented its potent antihypertensive effects in chapter 7. I’ve always had “normal” blood pressure by U.S. standards, but I wanted to shoot for optimal, so hibiscus became a daily staple for me. Give this recipe a try:
To two liters of water, add a handful of bulk dried hibiscus or four bags of tea in which hibiscus is the first ingredient. Then add the juice of one lemon and three tablespoons of erythritol, and leave it in your fridge to cold-brew overnight. In the morning, strain out the hibiscus or take out the tea bags, shake well, and drink throughout the day. That’s something I try to do every day I’m home.
For extra credit, add green foam: Pour 250 ml of the tea into a blender with a bunch of fresh mint leaves, blend on high, and enjoy. You end up with dark-green leafies blended into what may be the highest antioxidant beverage in the world, and it tastes like fruit punch. Your kids will love it!
As with any sour food or beverage, make sure to rinse your mouth with water after consumption to prevent the natural acids from dissolving your enamel.100 Do not brush your teeth within an hour after eating or drinking something sour, as your enamel may be in a softened state and be further damaged by brushing.101 If you sip continuously throughout the day, I suggest using a straw to bypass your teeth.102
Be careful, though. There are three ways that even harmless sweeteners could theoretically be harmful. Over the years, numerous large-scale studies have found a correlation between artificial-sweetener use and weight gain.103 The most common explanation for this counterintuitive finding is reverse causation: People aren’t fat because they drink diet fizzy drinks; they drink diet fizzy drinks because they’re fat.
But there are at least three other less benign alternative explanations. The first is called “overcompensation for expected caloric reduction.” If you covertly switch people’s fizzy drinks for diet soda without their knowing it, their caloric intake drops.104 This makes sense, since they’re not drinking all that sugar anymore. But what if you fess up to what you did? People who knowingly consume artificial sweeteners may actually end up eating more calories; they may figure after their zero-calorie drink, they can indulge in that second piece of pie. Indeed that’s what studies have shown. For example, if you give subjects an aspartame-sweetened cereal for breakfast, but only inform half the participants that the sweetener was artificial, when lunchtime comes, the aspartame-informed group ends up eating significantly more than the aspartame-naïve group.105 I think of this concept anytime I see someone at a fast-food restaurant ordering a diet fizzy drink with their meal.
A second explanation for gaining weight while using artificial sweeteners is based on how humankind evolved: When your brain registers the sensation of sweetness on your tongue, millions of years of evolution remind your brain to boost your appetite to eat as much as possible—after all, naturally sweet plant foods like fruits or sweet potatoes are among the healthiest. When you drink a can of diet fizzy drink, your brain thinks you just stumbled across a wild blueberry bush, and it sends urgent signals to eat large and eat fast before someone else gets wind of your bounty. At the same time, your body knows that if you eat too many calories, you might get too fat and not be able to outrun that saber-toothed tiger, so when your gut senses that you’ve absorbed enough calories, it sends signals up to your brain to urge you to stop eating. When you ingest low-calorie sweeteners, however, you experience the familiar hunger-boosting effect due to the sensation of sweetness on your tongue, yet you may lack the hunger-suppressing effect of calories entering your gut. The result can be a revved-up appetite that can lead to eating more food than you otherwise would have.106 That’s the second way diet fizzy drinks could counterintuitively lead to weight gain.
The third way involves maintaining cravings for, and dependency on, all things sweet. By continuing to consume any sweeteners—with or without calories—you are unable to train your flavor preferences away from intensely sweet foods.107 Let’s say that you use erythritol at home. That’s great, but what happens when you go on holiday and don’t have ready access to it? Your preference for intensely sweet food travels with you, and that may end up translating into the increased consumption of less-than-healthy foods.
The bottom line? Erythritol seems safe, but only if you don’t use it as an excuse to eat more junk food. With great sweetness comes great responsibility.
Drink five glasses of water a day, be they plain tap water or flavored with fruit, tea leaves, or herbs. Keeping hydrated may elevate your mood (and vigor!), improve your thinking, and even help cut your risk for heart disease, bladder cancer, and other diseases. Bottoms up!
Exercise
Moderate-Intensity Activities
Bicycling, canoeing, dancing, dodgeball, downhill skiing, fencing, hiking, housework, ice-skating, in-line skating, juggling, jumping on a trampoline, paddle boating, playing Frisbee, roller-skating, shooting baskets, shoveling light snow, skateboarding, snorkeling, surfing, swimming recreationally, tennis (doubles), treading water, walking briskly (4 mph), water aerobics, waterskiing, gardening, and yoga
Vigorous Activities
Backpacking, basketball, bicycling uphill, circuit weight training, cross-country skiing, football, hockey, jogging, jumping jacks, lacrosse, push-ups and pull-ups, racquetball, rock climbing, rugby, running, scuba diving, tennis (singles), skipping, soccer, speed skating, squash, step aerobics, swimming laps, walking briskly uphill, and water jogging
Serving Sizes:
90 minutes of moderate-intensity activity
40 minutes of vigorous activity
Daily Recommendation:
1 serving per day
More than two-thirds of American adults are overweight.1 Think about that. Fewer than one in three people maintain a healthy weight. What’s more, by 2030, more than half the country’s population may be clinically obese. Over the last three decades, childhood obesity has tripled, and most overweight kids will continue to be overweight into adulthood.2 As mentioned earlier, we may be in the process of raising the first generation of children in America with a shorter predicted life span than their parents.3
The food industries like to blame inactivity as the prime cause of obesity, not the promotion and consumption of their calorie-rich products.4 On the contrary, however, research suggests that the level of physical activity may have actually increased in the United States over the past few decades.5 We know that obesity is rising even in areas where people are exercising more.6 This is likely explained by the fact that eating activity levels are outstripping physical activity levels.7
Compared to ea
ting habits in the 1970s, every day, children are consuming the caloric equivalent of an extra can of fizzy drink and small fries, and adults are eating an extra Big Mac’s worth of calories. Just to make up for the extra calories Americans are taking in compared to a few decades ago, as a nation, we’d need to walk an extra two hours a day, every day of the week.8
Surveys suggest that most people believe controlling diet and getting enough exercise are equally important for weight control.9 It’s a lot easier to eat, however, than to move. To walk off the calories found in a single pat of butter or margarine, you’d have to add about an extra half mile to your evening stroll. For every additional sardine on your Caesar salad, that’s another quarter-mile jog. If you eat two chicken legs, you’ll need to get up on your own two legs and run three miles just to make up for it—and that’s stewed chicken, skin removed.10
Researchers who accept grants from the Coca-Cola Company11 call physical inactivity “the biggest public health problem of the 21st century.”12 Actually, physical inactivity ranks down at number five in terms of risk factors for death in the United States and number six in terms of risk factors for disability.13 And inactivity barely makes the top ten globally.14 As we’ve learned, diet is by far our greatest killer, followed by smoking.15
Of course, that doesn’t mean you should sit on the couch all day. As we’ve seen in this book, in addition to helping you enjoy a healthy body weight, exercise can also ward off and possibly reverse mild cognitive decline, boost your immune system, prevent and treat high blood pressure, and improve your mood and quality of sleep, among many other benefits. If the U.S. population collectively exercised enough to shave just 1 percent off the national body mass index (BMI), 2 million cases of diabetes, 1.5 million cases of heart disease, and up to 127,000 cases of cancer might be prevented.16
Stand Up for Your Health
It turns out your mum and dad were right about the hazards of watching too much television—although it may not rot the brain so much as the body. Based on a study of about nine thousand adults followed for seven years, researchers calculated that every additional hour spent watching TV per day may be associated with an 11 percent increased risk of death.17 Screen time in general—including playing video games—appears to be a risk factor for premature death.18 So does that mean you have to kill your TV and PlayStation before they kill you?
It’s not the electronics themselves but the sedentary behavior associated with enjoying them. Of course, not all sedentary behaviors are bad.19 Consider sleeping—you can’t be more sedentary than that! The problem appears to be sedentary sitting. After tracking the health of more than one hundred thousand Americans for fourteen years, an American Cancer Society study found that men who sit for six hours or more per day have a 20 percent higher overall death rate compared to men who sit for three hours or less, while women who sit for more than six hours have a 40 percent higher death rate.20 A meta-analysis of forty-three such studies found that excess sitting was associated with a shorter life span,21 and this may be “regardless of physical activity level.” In other words, people who religiously hit the gym after work may still have shortened life spans if they are otherwise sitting throughout the day. Sitting for six or more hours a day appears to increase mortality rates even among people who run or swim for an hour a day, every day, seven days a week.22
I’m not saying we should all quit our desk jobs, but there are other options. For instance, try switching to a standing desk, which elevates the heart rate and may burn as many as fifty extra calories per hour. This may not seem like a lot, but simply standing for three hours a day at work equates to about thirty thousand extra calories burned per year—the equivalent of running ten marathons.23 Whether you’re at the office, reading the newspaper at home, or, yes, even watching TV, why not find a way to stand while doing it? In fact, most of this book was written while I was walking fifteen miles a day on a treadmill underneath my standing desk. Prebuilt treadmill desks are expensive, but charity shops are often awash with old exercise equipment. My treadmill “desk” is just a treadmill stuck under some cheap plastic shelving.
If you have been sedentary for a long time, start out slowly. I’m sure you’ve heard the familiar refrain: “Before starting this or any other exercise program, be sure to check with your doctor.” This is definitely true for vigorous exercise, but most people can safely start to take up walking ten or fifteen minutes a few times a day. If, however, you are unsteady on your feet, prone to dizzy spells, or have a chronic or unstable health condition, it really is best to first consult with a health professional.
What If You Really Have to Sit All Day?
Why is sitting around so bad for you? One reason may be endothelial dysfunction, the inability of the inner lining of your blood vessels to signal your arteries to relax normally in response to blood flow. Just as your muscles atrophy if you don’t use them, “use it or lose it” may apply to arterial function as well. Increased blood flow promotes a healthy endothelium.24 Blood flow is what maintains the stability and integrity of the inner lining of your arteries. Without that constant tugging flow with each heartbeat of exertion, you can end up a sitting duck for arterial dysfunction diseases.
What if sitting all day is part of your job? Research suggests treadmill desks may improve the health of office workers without detracting from work performance,25 but your office might not accommodate a standing desk. Preliminary evidence from observational26 as well as interventional27 studies suggests that regular interruptions in sitting time can be beneficial. And they don’t have to be long. Breaks could be as short as one minute and not necessarily entail strenuous exercise—just walking up and down stairs may be enough. Another option at a sedentary workplace is to opt for “walking meetings” rather than traditional sit-downs.
What if you have a sitting job in which you can’t take frequent breaks, like truck driving? Is there any way to improve your endothelial function sitting on your butt? First you need to get rid of any butts—cigarette butts, that is. Smoking a single cigarette can significantly impair endothelial function.28 Diet-wise, drinking green tea every two hours can help keep your endothelium functional,29 as can eating meals with greens and other nitrate-rich vegetables. (See chapter 7.)
Turmeric may also help. One head-to-head study found that daily ingestion of the turmeric component curcumin can improve endothelial function just as well as up to an hour a day of aerobic exercise.30 Does that mean you can just be a couch potato as long as you eat curried potatoes? No, you still need to move around as much as possible—the combination of curcumin and exercise appears to work even better than either option alone.31
Treating Sore Muscles with Plants
Optimizing recovery from exercise is considered the holy grail of exercise science.32 Anyone who works out regularly knows about sore muscles. There’s the burning sensation during strenuous exercise, which may be related to the buildup of lactic acid in your muscles, and then there’s delayed-onset muscle soreness, the kind you get in the days following extreme physical activity. Delayed soreness is likely the result of inflammation caused by microtears in your muscles and can adversely affect athletic performance in the days following a heavy workout. If you’re suffering from an inflammatory reaction, might anti-inflammatory phytonutrients help? The bioflavonoids in citrus can help with the lactic acid buildup,33 but you may need to ramp up to the anthocyanin flavonoids in berries to deal with the inflammation.
Muscle biopsies of athletes have confirmed that eating blueberries, for example, can significantly reduce exercise-induced inflammation.34 Studies using cherries show that this anti-inflammatory effect can translate into faster recovery time, reducing the strength loss from excessive bicep curling from 22 percent down to only 4 percent in male college students over the subsequent four days.35 The muscle-soothing effects of berries don’t only work for weight lifters; follow-up studies have shown that cherries can also help reduce muscle pain in long-distance runners36 and aid in recovery fr
om marathons.37
Eating 300 grams of watermelon prior to intense physical activity was also found to significantly reduce muscle soreness. The researchers concluded that functional compounds in fruits and vegetables can “play a key role in the design of new natural and functional products” like beverages, juices, and energy bars.38 But why design new products when nature has already designed everything you need?
Preventing Exercise-Induced Oxidative Stress
As discussed in part 1, when you use oxygen to burn fuel in your body, free radicals can be produced, just as cars burning fuel produce combustion by-products out the exhaust. This happens even if you’re just idling, living your day-to-day life. What if you rev things up, start exercising, and really start burning fuel? Might you create more oxidative stress and therefore need to eat even more antioxidant-rich foods?
Studies have demonstrated that ultramarathoners show evidence of DNA damage in about 10 percent of their cells tested during39 and up to two weeks following40 a race. But most of us aren’t ultramarathoners. Might short bouts of exercise still damage your DNA?
Yes. After just five minutes of moderate or intense cycling, you can get an uptick in DNA damage.41 Never ones to miss an opportunity, pharmaceutical and supplement companies have investigated ways to block exercise-induced oxidative damage with antioxidant pills, but, ironically, this may lead to a state of pro-oxidation. For example, guys doing arm curls taking about 1,000 mg of vitamin C ended up with more muscle damage and oxidative stress.42
Instead of using supplements, what about using antioxidant-rich foods to douse the free radicals? Researchers led subjects onto treadmills and cranked up the intensity until they nearly collapsed. While a spike in free-radical levels was witnessed in the control group, subjects who loaded up on watercress two hours before exercising actually ended up with fewer free radicals after the treadmill test than when they started. After two months of eating a daily serving of watercress, no DNA damage resulted, no matter how much it seemed the subjects were punished on the treadmill.43 So, with a healthy diet, you can get the best of both worlds—all the benefits of strenuous exercise without excess free-radical damage. As a review in the Journal of Sports Sciences put it, those who eat plant-based diets may naturally “have an enhanced antioxidant defence system to counter exercise-induced oxidative stress.”44 Whether it’s about training longer or living longer, the science seems clear. Your quality and quantity of life improves when you choose green-light foods.
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