Eat, Drink, and Be Healthy

by Walter Willett

  The consequences of not taking in enough fluid each day range from the merely irritating to the life-threatening. Minor dehydration can make you feel grumpy and tired. Chronic minor dehydration is a cause of constipation, especially among older people. It can also contribute to the development of kidney stones and bladder cancer. Extreme dehydration, though relatively uncommon, can be deadly. It occurs mostly among children and older people during very hot weather, and among endurance athletes.

  Overhydration can be a problem too. Drinking too much water, sports drink, or any other beverage can throw off the body’s balance of water and minerals. It has led to the deaths of runners in the Boston and other marathons, several high school football players, and other athletes. One way to prevent overhydration, which can lead to a deadly condition known as hyponatremia, is to consume a balanced mix of water and minerals, such as Gatorade, when you are engaged in prolonged, intense activity.

  Think of hydration as a day-long process. Drink at least one glass of your beverage of choice soon after arising, with each meal, and in between meals. Drink before and after exercising. And drink if you are feeling thirsty.

  So far I have been deliberately general in talking about fluid intake rather than specifying any specific beverage. Plenty of beverages qualify for the task, including water, juice, soda, milk, coffee, tea, and alcohol. Some are better than others, especially as routine thirst quenchers. Let’s take a look at each one. The “healthy” list may surprise you.

  WATER

  For plain old topping off your tank, water is hard to beat. It has 100 percent of what you need—pure H2O—and no calories or additives. And when it comes from the tap, water costs a fraction of a penny per glass.

  In most cities across the United States, tap water is pure and healthy. In others, tap water contains lead, chromium, pesticides or herbicides, and other potentially dangerous chemicals that leach into water supplies from leaking underground storage tanks, factories and other businesses, landfills and garbage dumps, aging water pipes, and a variety of other sources. The possibility exists that the chlorine-based chemicals used to rid tap water of disease-causing bacteria can react with organic matter to create potentially cancer-causing compounds. So far, the available evidence doesn’t support that as serious health threat. To be on the safe side, though, we need to invest in public water treatment facilities that minimize the levels of these compounds.

  Many people believe that bottled water is safer than tap water. That’s not necessarily true. In fact, some bottled water actually comes from the tap, not from the pristine mountain springs conjured up by their names or the images on their labels. Bottled water doesn’t have to meet standards set by the federal Environmental Protection Agency that require regular testing for bacterial and chemical contamination. Tap water from public supplies, by comparison, must meet those standards and the reports must be made public.

  There’s also a widespread belief that bottled water tastes better than tap water. In blind taste tests, though, tap water often comes out on top. There are certainly exceptions, as some water systems have chlorine levels that give the water an “off” taste.

  In terms of cost, tap water is the clear winner. In Boston, it costs about $1.25 a year to drink eight glasses of tap water a day. Getting that much from bottled water would cost two hundred times more (about $225) if it’s from large home-delivery bottles or four hundred times more ($500) if it comes from individual bottles.

  There are also environmental considerations. It takes as much water to make disposable, individual-size water bottles as the bottle contains. Transporting bottled water uses fossil fuels and contributes to global warming. And many of the billions of bottles consumed each year in the United States end up in landfills or incinerators.

  The bottom line is that our public water supplies are generally very safe and that chlorination has saved countless lives by blocking the spread of infectious diseases. If there are risks to drinking tap water, they are generally very low compared with other “hazardous” habits. That said, some city water can be a health hazard, as we’ve sadly seen in Flint, Michigan. In such cases, drinking bottled water is an inexpensive and healthy alternative to drinking soda, juice, or other beverages in place of tap water.

  JUICE

  A glass of real fruit juice or vegetable juice tastes delightful. It also gives you water plus vitamins, minerals, and maybe some fiber. As a morning eye-opener or as a small part of your total fluid requirement, real juice (as opposed to juice-flavored sugar water) can be part of a healthy diet. In fact, scurvy, a disabling condition caused by a deficiency of vitamin C, was eliminated in the United States after World War II in part by the tradition of having a small glass of orange juice with breakfast. Orange juice also happens to be a good source of beta-cryptoxanthin, a healthful carotenoid that would otherwise be low in our diet.

  As a regular beverage, though, fruit juice can add a hefty daily dose of calories (see “Beware of liquid calories” on page 65). A 12-ounce serving of orange juice, for example, gives you 150 calories or so, or the equivalent of three chocolate-chip cookies or a can of sugar-sweetened soda. That’s an awful lot of calories if you just need something to quench your thirst.

  The fundamental problem with drinking juice is that it is just too easy to consume a large amount of fruit—and its accompanying sugar—in a few moments. Think of squeezing your own oranges to make a glass of juice. This would require about three oranges, depending on their size. Almost no one would eat three whole oranges at a sitting; spacing them out over a day would have a very gentle effect on your blood glucose. As juice, though, three oranges go down the hatch quite quickly, and you can do that several times a day if you aren’t careful.

  If you enjoy drinking juice, try diluting it with regular or sparkling water. Start with two parts juice to one part water and gradually work your way to one part juice to three or four parts water. Another trick for putting some zest into plain water is adding a squeeze of fresh lemon or lime. Vegetable juices tend to have fewer calories than fruit juices, but check the labels to be sure and look at the sodium content: some vegetable juices deliver nearly a day’s dose of sodium in a single serving.

  “Infused” Water: A Detox Myth

  * * *

  Can you flush “toxins” from your body by drinking water that’s been infused with a few slices of cucumbers, some grapefruit, and a few sprigs of mint? Media personalities like Dr. Oz, trainer Jillian Michaels, and celebrity Khloé Kardashian have touted the health benefits of “detox water,” which is made by letting water sit for a few hours with vegetables and fruits.

  What makes this detox water so magical? Nothing. For starters, no one can explain exactly what toxins this special water helps people eliminate. Any benefits—if there are any—come from drinking extra water. Adding grapefruit, cucumbers, or mint gives the water a pleasant taste but no detoxification power.

  The biggest problem with drinking fruit juice instead of water is that many people don’t eat less to adjust for the extra calories. That’s a surefire recipe for gradual weight gain.

  Among the many types of juices, grapefruit juice needs a special mention because it changes the way some people absorb and metabolize certain drugs. Grapefruit juice can reduce the absorption of the allergy medication fexofenadine (Allegra); digoxin, used to treat congestive heart failure; losartan (Cozaar), used to control blood pressure; and the anticancer drug vinblastine. Grapefruit juice can also boost the blood levels of other drugs, sometimes to dangerous heights. Drugs in this category include calcium channel blockers such as felodipine (Plendil), nifedipine (Procardia), and nisoldipine (Sular), which are used to control high blood pressure; carbamazepine (Carbatrol, Tegretol), used to control epilepsy; some widely used cholesterol-lowering medications such as lovastatin (Mevacor), atorvastatin (Lipitor), and simvastatin (Zocor); cyclosporine, an immunosuppressant taken mainly by people who have had an organ transplant; and buspirone (BuSpar), used to fight alcohol abuse, depre
ssion, panic disorder, and a variety of other problems.

  SODA AND OTHER SUGAR-SWEETENED BEVERAGES

  Imagine dumping seven to nine teaspoons of sugar onto a bowl of cereal. Too sweet to eat? That’s how much sugar is in a 12-ounce can of Coca-Cola, Pepsi, Orange Crush, or most other sugared soft drinks. We drink the stuff by the gallon—nearly five hundred 12-ounce servings of soda, pop, tonic, or whatever you call it per person each year, most of it the full-sugar variety. Keep in mind that this is the average, and many people consume several times that amount. That’s an awful lot of a beverage that has absolutely no nutritionally redeeming value.

  I say this because soda delivers pure calories completely divorced from the healthful nutrients you might get from real fruit juices—things such as vitamins, minerals, other phytochemicals, and maybe some fiber. That’s a problem on several levels.

  Most Americans already take in too many calories and struggle to lose weight. One 12-ounce serving of soda a day doesn’t seem like a big deal, especially if you manage to cut back on food calories. If you don’t, though, an extra 150 calories a day can translate into a 15-pound weight gain over a year! The danger of drinking sugared sodas and juices instead of water is that many people treat “liquid calories” as somehow different from “food calories” and often don’t make up for the calories in soda or juice by eating less.

  The simple sugars in soda trigger rapid and intense increases in blood sugar, which causes the pancreas to pump out more and more insulin. When this happens several times a day on top of the rises in blood sugar and insulin that occur after eating, it can increase the risk of type 2 diabetes, especially for people who are growing more and more resistant to insulin’s ability to ferry glucose inside cells. In a meta-analysis that included nearly 500,000 men and women followed for an average of twenty-two years, the risk of developing type 2 diabetes went up by 13 percent for each daily serving of sugar-sweetened soda or juice.4 Given the rate of soda consumption in the United States, that would translate into 1.8 million new cases of type 2 diabetes over a ten-year period. Notably, this increase in risk was on top of the contribution of soda to weight gain, which itself is a powerful risk factor for diabetes. Taking in lots of easily digested carbohydrates—like those found in soda—raises the blood level of triglycerides, a kind of fat-carrying particle, and depresses the level of HDL cholesterol. Both of these changes would tilt the scales in the direction of heart disease. Not surprisingly, that is exactly what we found when studying soda consumption in the Nurses’ Health Studies.5

  Drinking a fair amount of sugar-sweetened soda also appears to boost the odds of developing painful kidney stones. In the Nurses’ Health Study and the Health Professionals Follow-Up Study, participants who drank one or more sugar-sweetened sodas a day were 33 percent more likely to have developed kidney stones over an eight-year period than those who drank less than one serving a week.6

  What about calorie-free sodas, often called diet sodas? The FDA has approved six sugar substitutes for use in foods and beverages—advantame (no brand name yet), aspartame (Equal and NutraSweet), acesulfame potassium (Sweet One), neotame (Newtame), saccharin (Sweet’N Low), and sucralose (Splenda). Two other so-called nonnutritive sweeteners, Stevia and extracts of the Swingle or monk fruit, are derived from plants, so they aren’t “artificial.” Instead, they fall into the FDA’s “generally recognized as safe” category.7

  As a beverage, diet sodas are better than the sugared versions, although they’re an expensive way to get water. As a weight-loss gambit, don’t count on this approach all by itself. Artificial sweeteners may affect the body’s ability to gauge how many calories are coming in.8 Our brains respond to sweetness with signals to eat more. By providing a sweet taste without any calories, artificial sweeteners may cause us to crave more sweet foods and drinks, which can add up to extra calories. The relation between diet soda and obesity is complicated to study because many people who are overweight switch to diet soda with the hope of losing weight, making it difficult to determine cause and effect—a simple analysis done at one point in time may show that consumption of diet soda is associated with overweight and obesity. My colleagues and I have looked at this carefully over time. Men and women who consumed diet soda gained less weight than those who consumed sugar-sweetened soda.9 A similar trend was seen in a randomized trial conducted among adolescents that compared sugared and diet sodas.10 In the same way, after taking into account the tendency of overweight people to select diet soda, consumption of this beverage does not appear to increase the risk of diabetes.

  Despite what you might read on the Internet or hear in the popular press, nonnutritive sweeteners probably don’t pose a health hazard for adults. However, the reality is that most of these have not been examined adequately in long-term human studies. No one knows how they affect children, who may consume large amounts of them over a lifetime.

  Why bother with the uncertainty when plain water or water with a twist of lemon or a dash of juice is a healthier option? My bottom line: Think of diet soda as you might a nicotine patch for smoking. It may help wean you from drinking sugar-sweetened soda, but you don’t want to rely on it for the long haul.

  MILK

  Milk from cows, sheep, goats, and other species is a brew of high-quality proteins, minerals such as calcium and phosphorous, hormones, and other nutrients that make baby animals—including humans—grow fast. For very young children, it’s a good but second-best alternative to breast milk. For older children, it can help promote growth. Milk and dairy foods may be good for elderly individuals who need extra protein and other nutrients. But for adolescents and most adults, there is potential harm in drinking too much milk. That’s why I believe that you should think of milk and other dairy foods as optional parts of your diet to be consumed in modest amounts, not something you need to drink or eat two or three times a day.

  The Dietary Guidelines for Americans have long recommended that most Americans get three servings of milk or other dairy foods a day. That recommendation was enshrined in the old Food Guide Pyramid and resurrected in MyPlate. The 2015–2020 Dietary Guidelines for Americans say that a healthy eating plan includes fat-free or low-fat dairy, including milk, yogurt, cheese, and/or fortified soy beverages, and still set three servings a day as the target for most people.

  The main rationale is that milk and other dairy foods give us the calcium we need to strengthen bones. Milk has also been touted as a weight-loss food.

  But as I point out in chapter ten, we don’t need two to three servings of dairy foods a day to prevent osteoporosis and fractures, and many Americans may be getting too much calcium. The evidence doesn’t support the link between drinking milk and long-term body weight, although eating yogurt may help control weight.11

  You may be thinking, If I’m not getting enough calcium every day, why not play it safe and drink three glasses of milk a day? Here are several good reasons: lactose intolerance, extra saturated fat, extra calories, unneeded hormones, possible increased risks of heart disease or cancer, and environmental problems.

  Lactose intolerance. All babies are born with the ability to digest milk. Some, especially those of northern European ancestry, keep this trait for life. Most children, though, gradually lose it as their bodies stop making an enzyme called lactase that breaks down milk sugar (lactose). In fact, only about a quarter of the world’s adults can fully digest milk. In the United States, as many as 50 million Americans aren’t equipped to digest milk. Half of Hispanic Americans, 75 percent of African Americans, and more than 90 percent of Asian Americans can’t tolerate much lactose. For them, drinking a glass of milk can have unpleasant consequences, such as nausea, bloating, cramps, and diarrhea.

  A lot of effort has gone into helping lactose-intolerant people drink milk or eat cheese or ice cream. The Agriculture Research Service (part of the USDA) touts its development of the lactose-modified milk known as Lactaid as one of its top accomplishments in the last fifty years. A variety of lactose-dige
sting powders or tablets that can be added to milk or taken before eating dairy products are available over the counter. And dairy proponents point to a number of studies showing that people who have trouble digesting lactose can tolerate small amounts throughout the day, especially when consumed with other food. But because there are easier ways to get enough calcium, I don’t believe that people who have trouble digesting lactose need to spend the extra money or time drinking milk or eating dairy products. It is perfectly fine if you want to do that, but you shouldn’t force yourself to do it or feel guilty if you don’t. After all, you’re in good company with three-quarters of the world’s adults.

  Saturated fat. An 8-ounce glass of whole milk contains almost 5 grams of saturated fat. Drinking three glasses a day would be the equivalent of eating twelve strips of bacon or a Big Mac and an order of fries. That’s a substantial amount of saturated fat. Cheese can also deliver a lot of saturated fat. A 1-ounce serving of American cheese made from whole milk delivers about as much calcium as a glass of milk and the same amount of saturated fat.

  Despite confusion in both the scientific and general media, saturated fat is a real health concern. As discussed in chapter five, saturated fat was once over-vilified as uniquely harmful and the primary cause of heart disease. We now know that trans fat has a more harmful effect on the cardiovascular system, and saturated fat is about the same, calorie for calorie, as refined starch and sugar. If you are aiming to optimize your health, replacing butter and other sources of dairy fat with unsaturated plant oils is a good step in that direction.

  That isn’t to say that you should entirely eliminate milk, cheese, and ice cream. If you really like them, eat them in modest amounts, buy the best quality you can afford, and enjoy them.

  You might think that if enough people made the switch to low-fat or skim milk, lower rates of heart disease would follow. But that won’t happen, at least not at the population level. That’s because once a cow is milked, the fat from that milk is in the food supply, and someone ends up drinking or eating it. Much of the fat skimmed from milk resurfaces as butter and cream, which are used to make premium ice cream, buttery pastries, and high-fat snack foods such as cookies and candy bars. Many of the same people who have switched to skim milk have a bowl of high-fat Ben & Jerry’s or Häagen-Dazs ice cream before going to bed, and people who drink whole milk or don’t drink milk at all—often poorer, less educated, or less health-savvy people—are eating more and more high-fat products made with milk fat.