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18.2: Comparing Diets

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    Skills to Develop

    • Learn about various diet trends and the effect on health

    In the past, health was regarded merely as the absence of illness. However, a growing understanding of the complexity and potential of the human condition has prompted a new way of thinking about health. Today, we focus on the idea of wellness, which involves a great deal more than just not being sick. Wellness is a state of optimal well-being that enables an individual to maximize their potential. This concept includes a host of dimensions—physical, mental, emotional, social, environmental, and spiritual—which affect one’s quality of life.[1] Striving for wellness begins with an examination of dietary choices.

    Dietary Food Trends

    Hundreds of years ago, when food was less accessible and daily life required much more physical activity, people worried less about obesity and more about simply getting enough to eat. In today’s industrialized nations, conveniences have solved some problems and introduced new ones, including the hand-in-hand obesity and diabetes epidemics. Fad diets gained popularity as more North Americans struggled with excess pounds. However, new evidence-based approaches that emphasize more holistic measures are on the rise. These new dietary trends encourage those seeking to lose weight to eat healthy, whole foods first, while adopting a more active lifestyle. These sound practices put dietary choices in the context of wellness and a healthier approach to life.

    everyday connections

    In the past, people’s culture and location determined the foods they ate and the manner in which they prepared their meals. For example, in Hawai’i, taro was a staple complex carbohydrate that could be eaten in various ways such as poi and pa’ia’i. Today, most people have access to a wide variety of food and can prepare them any way they choose. However, customs and traditions still strongly influence diet and cuisine in most areas of the world. To learn more about the food and culture in the pacific, visit http://manoa.hawaii.edu/ctahr/pacificfoodguide/index.php/regional-information/

    Functional Foods

    Many people seek out foods that provide the greatest health benefits. This trend is giving rise to the idea of functional foods, which not only help meet basic nutritional needs but also are reported to fight illness and aging. According to the Academy of Nutrition and Dietetics (AND), formerly known as the The American  Dietetic Association, functional foods may reduce the risk of disease or promote optimal health. The AND recognizes four types of functional foods. They are: conventional foods, modified foods, medical foods, and special dietary use foods.[2]

    The first group, conventional foods, represents the simplest form of functional foods. They are whole foods that have not been modified. Examples include whole fruits and vegetables (which are abundant in phytochemicals and antioxidants), yogurt and kefir (which contain natural probiotic bacteria that can help maintain digestive system health), and moderate amounts of dark chocolate, made with 70% or more cacao (which contains antioxidants).

    Modified foods have been fortified, enriched, or enhanced with additional nutrients or bioactive compounds. Foods are modified using biotechnology to improve their nutritional value and health attributes. Examples of modified foods include calcium-fortified orange juice, breads enriched with B vitamins, iodized salt, cereals fortified with vitamins and minerals, margarine enhanced with plant sterols, and energy drinks that have been enriched with herbs (ginseng or guarana) or amino acids (taurine). It is important to consider that the health claims of some modified foods may be debatable, or entirely fraudulent. Check with a health professional regarding the effects of modified foods on your health.

    Medical foods are designed for enteric administration under the guidance of a medical professional. (During enteric administration, food is treated so that it goes through the stomach undigested. Instead, the food is broken down in the intestines only.) Medical foods are created to meet very specific nutritional requirements. Examples of medical foods include liquid formulas for people with kidney disease, liver disease, diabetes, or other health issues. Medical food is also given to comatose patients through a gastronomy tube because they cannot eat by mouth.

    Special dietary use foods do not have to be administered under a doctor’s care and can be found in a variety of stores. Similar to medical foods, they address special dietary needs and meet the nutritional requirements of certain health conditions. For example, a bottled oral supplement administered under medical supervision is a medical food, but it becomes a special dietary use food when it is sold to retail customers. Examples of special dietary use foods include gluten-free foods, lactose-free dairy products, and formulas and shakes that promote weight loss.

    Popular Diets

    The concept of functional foods represents initiatives aimed at addressing health problems. Certain diet plans take this concept one step further, by striving to prevent or treat specific conditions. For example, it is widely understood that people with diabetes need to follow a particular diet. Although some of these diet plans may be nutritionally sound, use caution because some diets may be fads or be so extreme that they actually cause health problems.

    Before experimenting with a diet, discuss your plans with your doctor or a registered dietitian. Throughout this section, we will discuss some of the more popular diets. Some fall under the category of fad diets, while others are backed by scientific evidence. Those that fall into the latter category provide a good foundation to build a solid regimen for optimal health.

    The DASH Diet

    The Dietary Approaches to Stop Hypertension, or DASH diet, focuses on reducing sodium intake to either 2,300 milligrams per day (as recommended by the Dietary Guidelines for Americans) or 1,500 milligrams per day for certain populations. The DASH diet is an evidence-based eating plan that can help reduce high blood pressure. This plan may also decrease the risk of heart attack, stroke, diabetes, osteoporosis, and certain cancers.[3]

    DASH tips to lower sodium include:

    • Using spices instead of salt to add flavor
    • Reading sodium content on processed or canned food labels, and choosing low-sodium options
    • Removing some sodium from canned foods (such as beans) by rinsing the product before consumption
    • Avoiding salt when cooking

    DASH dieters are recommended to consume a variety of whole grains and high-fiber fruits and vegetables, and moderate amounts of low-fat dairy products, lean meats, and heart-healthy fish. In addition, DASH limits the use of saturated fats to less than 7 percent of total calories, and limits the consumption of sweets and alcohol. The DASH diet also calls for consuming less added sugar and drinking fewer sugar-sweetened drinks. It replaces red meat with fish and legumes and calls for increased calcium, magnesium, potassium, and fiber. Also, even though some people on the DASH diet may find it lowers their HDL (good) cholesterol along with their LDL (bad) cholesterol, it still has a positive cumulative effect on heart health.[4]

    The Gluten-Free Diet

    The gluten-free diet helps people whose bodies cannot tolerate gluten, a protein found in wheat, barley, and rye. One of the most important ways to treat this condition is to avoid the problematic foods, which is not easy. Although following a gluten-free diet is challenging, it is prescribed for patients with gluten intolerance and celiac disease, an autoimmune disorder with a genetic link. People who have celiac disease cannot consume gluten products without damaging their intestinal lining. Eating a gluten-free diet means finding replacements for bread, cereal, pasta, and more. It also means emphasizing fresh fruits, vegetables, and other foods without gluten. However, it is important to note that the gluten-free trend has become something of a fad even for those without a gluten intolerance. Celiac disease is a relatively rare condition found in only 1 percent of the population. Therefore, a gluten-free diet should be followed only with a physician’s recommendation.

    Low-Carb Diets

    Low-carb diets, which include the Atkins Diet and the South Beach Diet, focus on limiting carbohydrates—such as grains, fruit, and starchy vegetables—to promote weight loss. The theory behind the low-carb diet is that insulin prevents the breakdown of fat by allowing sugar in the form of blood glucose to be used for energy. Proponents of this approach believe that because limiting carbs generally lowers insulin levels, it would then cause the body to burn stored fat instead. They believe this method not only brings about weight loss, but also reduces the risk factors for a number of conditions. However, some studies have shown that people who followed certain low-carb diet plans for two years lost an average of nearly 9 pounds, which is similar to the amount of weight lost on higher carbohydrate diets.[5]

    The benefits of this kind of diet include an emphasis on whole, unprocessed foods and a de-emphasis of refined carbohydrates, such as white flour, white bread, and white sugar. However, there are a number of downsides. Typically, the first two weeks allow for only 20 grams of carbs per day, which can be dangerously low. In addition, dieters using the low-carb approach tend to consume twice as many saturated fats as people on a diet high in healthy carbohydrates. Low-carb diets are also associated with a higher energy intake, and the notion that “calories don’t count,” which is prevalent in this kind of diet, is not supported by scientific evidence.[6]

    The Macrobiotic Diet

    The macrobiotic diet is part of a health and wellness regimen based in Eastern philosophy. It combines certain tenets of Zen Buddhism with a vegetarian diet and supports a balance of the oppositional forces of yin and yang. Foods are paired based on their so-called yin or yang characteristics. Yin foods are thought to be sweet, cold, and passive, while yang foods are considered to be salty, hot, and aggressive.

    Whole grains make up about 50 percent of the calories consumed and are believed to have the best balance of yin and yang. Raw and cooked vegetables comprise about 30 percent of the diet and include kale, cabbage, collards, bok choy, and broccoli on a daily basis, along with mushrooms and celery a few times a week. Bean or vegetable-based soups and broths can make up 5 to 10 percent of daily caloric intake. Additionally, the diet allows small amounts of fish and seafood several times a week, along with a few servings of nuts. The macrobiotic diet prohibits certain foods, such as chocolate, tropical fruits, and animal products, because they are believed to fall on the far end of the yin-yang spectrum, which would make it difficult to achieve a Zen-like balance.

    The macrobiotic diet focuses on foods that are low in saturated fats and high in fiber, which can help to lower the risk of cardiovascular disease. Proponents of this diet also believe that it may protect against cancer. However, many nutritionists and healthcare providers express concerns, particularly if the diet is followed strictly. Extreme macrobiotic eating can be low in protein, low in calories, and pose a risk for starvation. In addition, the diet is also very low in essential vitamins and minerals.[7]

    The Mediterranean Diet

    The traditional Mediterranean diet incorporates many elements of the dietary choices of people living in Greece and southern Italy. The Mediterranean diet focuses on small portions of nutritionally-sound food. This diet features food from plant sources, including vegetables, fruits, whole grains, beans, nuts, seeds, breads and potatoes, and olive oil. It also limits the consumption of processed foods and recommends eating locally grown foods rich in micronutrients and antioxidants. Other aspects of this eating plan include consuming fish and poultry at least twice per week, eating red meat only a few times per month, having up to seven eggs per week, and drinking red wine in moderation. Unlike most diets, the Mediterranean diet does not cut fat consumption across the board. Instead, it incorporates low-fat cheese and dairy products, and it substitutes olive oil, canola oil, and other healthy oils for butter and margarine.

    More than fifty years of nutritional and epidemiological research has shown that people who follow the Mediterranean diet have some of the lowest rates of chronic disease and the highest rates of longevity among the populations of the world. Studies have shown that the Mediterranean diet also helps to decrease excess body weight, blood pressure, blood fats, and blood sugar and insulin levels significantly.[8]

    Tools for Change

    For six years, researchers from the University of Bordeaux in France followed the dietary habits of more than seven thousand individuals age sixty-five and over. Participants who described greater consumption of extra-virgin olive oil reportedly lowered their risk of suffering a stroke by 41 percent. The study controlled for stroke risk factors, such as smoking, alcohol intake, high blood pressure, and a sedentary lifestyle. To increase the amount of olive oil in your diet, try spreading olive oil instead of butter on your toast, making your own salad dressing using olive oil, vinegar or lemon juice, and herbs, cooking with olive oil exclusively, or simply adding a dose of it to your favorite meal.[9]

    The Raw Food Diet

    The raw food diet is followed by those who avoid cooking as much as possible in order to take advantage of the full nutrient content of foods. The principle behind raw foodism is that plant foods in their natural state are the most wholesome for the body. The raw food diet is not a weight-loss plan, it is a lifestyle choice. People who practice raw foodism eat only uncooked and unprocessed foods, emphasizing whole fruits and vegetables. Staples of the raw food diet include whole grains, beans, dried fruits, seeds and nuts, seaweed, sprouts, and unprocessed produce. As a result, food preparation mostly involves peeling, chopping, blending, straining, and dehydrating fruits and vegetables.

    The positive aspects of this eating method include consuming foods that are high in fiber and nutrients, and low in calories and saturated fat. However, the raw food diet offers little in the way of protein, dairy, or fats, which can cause deficiencies of the vitamins A, D, E, and K. In addition, not all foods are healthier uncooked, such as spinach and tomatoes. Also, cooking eliminates potentially harmful microorganisms that can cause foodborne illnesses. Therefore, people who primarily eat raw foods should thoroughly clean all fruit and vegetables before eating them. Poultry and other meats should always be cooked before eating.[10]

    Vegetarian and Vegan Diets

    Vegetarian and vegan diets have been followed for thousands of years for different reasons, including as part of a spiritual practice, to show respect for living things, for health reasons, or because of environmental concerns. For many people, being a vegetarian is a logical outgrowth of “thinking green.” A meat-based food system requires more energy, land, and water resources than a plant-based food system. This may suggest that the plant-based diet is more sustainable than the average meat-based diet in the U.S.By avoiding animal flesh, vegetarians hope to look after their own health and that of the planet at the same time. Broadly speaking, vegetarians eat beans, grains, and fruits and vegetables, and do not eat red meat, poultry, seafood, or any other animal flesh. Some vegetarians, known as lacto vegetarians, will eat dairy products. Others, known as lacto-ovo vegetarians, will eat dairy products and eggs. A vegan diet is the most restrictive vegetarian diet—vegans do not eat dairy, eggs, or other animal products, and some do not eat honey.

    Vegetarian diets have a number of benefits. Well-balanced eating plans can lower the risk of a number of chronic conditions, including heart disease, diabetes, and obesity. They also help to promote sustainable agriculture. However, if a vegetarian does not vary his or her food choices, the diet may be insufficient in calcium, iron, omega-3 fatty acids, zinc, and vitamin B12. Also, if people who follow these diets do not plan out their meals, they may gravitate toward foods high in fats.

    Table \(\PageIndex{1}\): The Pros and Cons of Seven Popular Diets.

    Diet Pros Cons
    DASH Diet

    Recommended by the National Heart, Lung, and Blood Institute, the American Heart Association, and many physicians

    Helps to lower blood pressure and cholesterol

    Reduces risk of heart disease and stroke

    Reduces risk of certain cancers

    Reduces diabetes risk

    There are very few negative factors associated with the DASH diet

    Risk for hyponatremia

    Gluten-Free Diet

    Reduces the symptoms of gluten intolerance, such as chronic diarrhea, cramping, constipation, and bloating

    Promotes healing of the small intestines for people with celiac disease, preventing malnutrition

    May be beneficial for other autoimmune diseases, such as Parkinson’s disease, rheumatoid arthritis, and multiple sclerosis

    Risk of folate, iron, thiamin, riboflavin, niacin, and vitamin B6 deficiencies

    Special gluten-free products can be hard to find and expensive

    Requires constant vigilance and careful food label reading, since gluten is found in many products

    Low-Carb Diet

    Restricts refined carbohydrates, such as white flour and white sugar

    May temporarily improve blood sugar or blood cholesterol levels

    Not entirely evidence-based

    Results in higher fat and protein consumption

    Does not meet the RDA for carbohydrates to provide glucose to the brain

    Macrobiotic Diet

    Low in saturated fats and high in fiber

    Emphasizes whole foods and de-emphasizes processed foods

    Rich in phytoestrogens, which may reduce the risk of estrogen-related cancers

    Not entirely evidence-based

    Lacks certain vitamins and minerals; supplements are often required

    Can result in a very low caloric intake

    Lack of energy may result from inadequate protein

    Mediterranean Diet

    A reduced risk of cardiovascular disease and mortality

    A lower risk of cancer

    De-emphasizes processed foods and emphasizes whole foods and healthy fats

    Lower sodium intake, due to fewer processed foods

    Emphasis on monosaturated fats leads to lower cholesterol

    Highlighting fruits and vegetables raises consumption of antioxidants

    Does not specify daily serving amounts

    Potential for high fat and high calorie intake as nuts and oils are calorie-dense foods

    Drinking one to two glasses of wine per day may not be healthy for those with certain conditions

    Raw Food Diet

    Emphasizes whole foods

    Focuses on nutritionally-rich foods

    Not entirely evidence-based

    Very restrictive and limits protein and healthy fat intake

    Could encourage the development of foodborne illness

    Extremely difficult to follow

    High in fiber which can cause essential nutrient deficiencies

    Vegetarianism and Veganism

    May reduce some chronic diseases such as cancer, heart disease, and Type 2 diabetes

    May help with weight reduction and weight maintenance

    Guidelines regarding fat and nutrient consumption must be followed

    Higher risk for nutrient deficiencies such as protein, iron, zinc, omega-3, vitamin B12

    Consumption of a high fiber diet interferes with mineral and nutrient bioavailability

    Vegetarian and vegan protein sources are lower quality with majority missing at least one essential amino acids

    Footnotes 

    1. Understanding Wellness. University of Illinois at Urbana-Champaign, McKinley Health Center.   2011 The Board of Trustees of the University of Illinois at Urbana-Champaign. https://mckinley.illinois.edu/health-education/wellness. Accessed April 15, 2018. 
    2. Functional Foods. The Academy of Nutrition and Dietetics. https://www.eatright.org/food/nutrition/healthy-eating/functional-foods. Published July 5, 2018. Accessed April 15, 2018. 
    3. DASH Diet Eating Plan. DASH Diet Oregon.  http://www.dashdietoregon.org/. Accessed April 12, 2018. 
    4. DASH Diet Eating Plan. DASH Diet Oregon. http://www.dashdietoregon.org/. Accessed April 12, 2018. 
    5. Low-Carb Diet: Can It Help You Lose Weight?.The Mayo Clinic.  http://www.mayoclinic.com/health/low...b-diet/NU00279. Accessed March 6, 2018. 
    6. Steele V. Health and Nutritional Effects of Popular Diets. Kellogg Nutrition Symposium, The Team of Registered Dietitians & Nutrition Professionals at Kellogg Canada Inc. Insert to Canadian Journal of Dietetic Practice and Research 64, no. 3. 
    7. Zelman, KM. Macrobiotic Diet. http://www.webmd.com/diet/features/macrobiotic-diet. Updated February 9, 2018. Accessed April 12, 2018. 
    8. Robinson, K. The Mediterranean Diet. http://www.webmd.com/diet/features/the-mediterranean-diet. Published February 6, 2018. Accessed April 15, 2018. 
    9. More Olive Oil in Diet Could Cut Stroke Risk: Study. MedicineNet.com. https://www.medicinenet.com/script/main/art.asp?articlekey=145823. Published 2011. Accessed April 15,2018. 
    10. Raw Food Diet. WebMD.com.https://www.webmd.com/diet/a-z/raw-foods-diet. Published November 21, 2016. Accessed April 15, 2018. 

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